Hurricanes 2007

New Thread.

421 Comments

  1. David Smith
    Posted Sep 6, 2007 at 6:22 AM | Permalink

    Thanks, Steve M.

    Re Judith’s article on new classifications ( link ), at least a few of the private forecasters (the ones you pay to access) have indices that incorporate a wide range of factors. It’s a good concept. Some help educate their clients by calculating the indices for historical storms which hit their clients’ locales, so that people can mentally compare the magnitudes.

  2. David Smith
    Posted Sep 6, 2007 at 6:35 AM | Permalink

    And speaking of indices, here are the 2007 to-date ACE values for the storms. ACE for a hurricane season incorporates storm count, intensity and duration and gives a better indication of a season’s activity than storm count alone:

    The normal ACE for an Atlantic season is 100.

    Dean: 34
    Felix: 16
    Barry: 0.8
    Chantal: 0.6
    Erin: 0.2

    Total: about 52

    At this point in a typical season about 40% of the ACE has happened, so maybe we’ll see a 2007 ACE of around 130. I am beginning to have my doubts, though, as the Atlantic atmosphere continues to look anomalously stable.

  3. Hoi Polloi
    Posted Sep 6, 2007 at 7:55 AM | Permalink

    Looking back:

    2006 Hurricane Forecast: More and Bigger

    Bad news for those who’ve been hoping the last hurricane season was a fluke. The director of the National Hurricane Center says there’s no reason to expect any relief in the near future.

    In fact, the El Nino effect could stir up even more and bigger hurricanes in 2006 than in 2005, Max Mayfield warned a conference of insurance adjusters in Orlando.

    Homeowners in hurricane-prone areas should prepare now for the next storm season, Mayfield said. Minor repairs, like loose shingles, need to be taken care of before the next hurricane hits or major damage may result.

    Mayfield also expressed concern about homeowners’ reluctance to evacuate when hurricanes are approaching. He noted that only 10 percent of residents in the Florida Keys, for example, heeded evacuation orders.

    “If it looks like there is going to be a tidal surge, you have to flee the water, according to Insurance Journal. “If there is a large storm surge, it doesn’t matter how well a house is built, or what it is built from, the flooding is going to enter the house and no matter how tall you are, it won’t help.”

    Insurance adjusters, yeah right, adjusted… upwards…

  4. Posted Sep 6, 2007 at 8:04 AM | Permalink

    The insurance industry can justify increased rates even more if pessimistic predictions are accepted. The doom and gloom doesn’t happen, then they’ll keep the profits.

  5. Rick
    Posted Sep 6, 2007 at 10:37 AM | Permalink

    Hurricanes are powered by water temperature, is that right? So naturally warming water should be a concern – so I checked for a graph and sure enough water temp has been going up since 1880. Presuming 1880 water temp measurement science was as exact and robust as it is today, and knowing the history that Galveston got smacked really good about 4 times in the cooler water period, I suppose everybody should get the heck away from the gulf. It can only get worse.

    Yep – I’m staying out of there!

  6. Kenneth Fritsch
    Posted Sep 6, 2007 at 10:58 AM | Permalink

    It’s a good concept. Some help educate their clients by calculating the indices for historical storms which hit their clients’ locales, so that people can mentally compare the magnitudes.

    It would appear rather obvious that not a single hurricane and tropical storm index will fit all needs. For potential storm damage one might want something different than for relating SST to storm frequency and intensity. I would agree that the current categorization of hurricanes has probably outlived its usefulness, but I can see (from my own earlier struggles converting from English to decimal metrics not mathematically but visualizing) where a long used and more comfortably visualized system is difficult to change. As you say David, education would be the key.

    Another note I want to sneak in here is Steve S’s constant reminders of using the tiny dinky storms in the count. While I agree that this over counting and category changing makes direct historical comparisons more difficult, I had very carefully factored that tendency into my 2007 prediction model (and I assume David Smith that you have also) and that Steve S you had every opportunity to do the same.

  7. VirgilM
    Posted Sep 6, 2007 at 11:05 AM | Permalink

    There is more to the formation of hurricanes than sea surface temperature. The wind aloft environment is a huge player. If the winds aloft are too strong, then a hurricane is not allowed to organize. This environment is difficult to determine months in advance and is the number one source of uncertainity for hurricane number forecasts.

    There is a huge debate on whether the recent climate change will result in an increase in hurricanes. Think it was hard the last two years? It will be much harder to figure out all the factors related to hurricanes 50 years from now. Hence the huge debate.

  8. Gunnar
    Posted Sep 6, 2007 at 11:05 AM | Permalink

    >> Hurricanes are powered by water temperature, is that right?

    Yup. But:

    The passage of a tropical cyclone over the ocean can cause the upper layers of the ocean to cool substantially, which can influence subsequent cyclone development. Cooling is primarily caused by upwelling of cold water from deeper in the ocean due to the wind stresses the storm itself induces upon the sea surface. Additional cooling may come in the form of cold water from falling raindrops. Cloud cover may also play a role in cooling the ocean, by shielding the ocean surface from direct sunlight before and slightly after the storm passage. All these effects can combine to produce a dramatic drop in sea surface temperature over a large area in just a few days. .. cyclone releases heat energy at the rate of 50 to 200 trillion joules per day (http://en.wikipedia.org/wiki/Hurricanes)

    >> It can only get worse. Yep – I’m staying out of there!

    I think we’re past the modern solar maximum, so it might not get worse.

  9. SteveSadlov
    Posted Sep 6, 2007 at 12:08 PM | Permalink

    RE: #2 – So stable, in fact, that the count padders are scraping the bottom of the barrel, naming cut off lows, occluded fronts and mesocyclones.

  10. SteveSadlov
    Posted Sep 6, 2007 at 12:13 PM | Permalink

    RE: #7 – There is a method to my madness. At the end of the season, undoubtedly, we’ll have a padded BS count, and, we’ll have the real count that I am keeping. My prediction was purposely “low” against the padded count. I am highly confident that it is either spot on or perhaps even a wee bit high against the real count. There is a small possibility that my bet will even be realized by the padded count, in which case, the point would be brought home even more strongly. ;)

  11. Bill F
    Posted Sep 6, 2007 at 12:19 PM | Permalink

    Actually, hurricanes depend on the temperature differential between the sea surface and the upper troposphere. If the sea surface is warming at a slower rate than the upper troposphere, which is what AGW theory would suggest, then it should harder and not easier for hurricanes to form if all other factors remain the same…which there is no reason to believe will be the case.

  12. Bob Koss
    Posted Sep 6, 2007 at 3:06 PM | Permalink

    My position is that 2005 wasn’t as bad as 1950. Thay had more major storms and 20% more tracks achieved hurricane force even though there were only 11 hurricanes. Anyone want to bet as to whether they counted every niggling little low pressure system back then?

  13. windansea
    Posted Sep 6, 2007 at 3:10 PM | Permalink

    the recent “surge” in Hurricanes is just a return to normal according to this recent proxy research.

    http://www.worldclimatereport.com/index.php/2007/08/31/more-hurricane-news/#more-262

  14. Posted Sep 6, 2007 at 3:11 PM | Permalink

    Bill F

    But we are seeing just the oposite. A few years ago (about 30 years) I was taken measurements from the air immediately above the sea surface and it was some 1.3 K higher that the temperature at 2.5 m above the sea surface. I think that the T above 2.5 m could be lower and so on. Actually, I consider the current is a very normal season regarding hurricans and there is not a scientific reason to think that the warming of the oceans’ surface will produce more and more devastating hurricanes.

  15. UK John
    Posted Sep 6, 2007 at 4:32 PM | Permalink

    We may well be over-recording Hurricanes, but that is what we should expect!

    This really is just a human physchology problem, we want to believe we can affect the planet, we always have.

    Every human civilisation has believed this, it is in our nature, this is who we are.

    Our very existence used to depend on our ability to read and react to the Climate, and it will be difficult to change.

    This should be factored into every subjective or objective assessment of the Climate, even the ones made by climate audit.

  16. David Smith
    Posted Sep 6, 2007 at 6:49 PM | Permalink

    As mentioned, the to-date Atlantic ACE is 52 (normal full season is 100). How’s the rest of the Northern Hemisphere doing?

    Well, to-date:

    Western Pacific ACE = 110 (normal full season is 300)

    East/Central Pacific ACE = 40 (normal full season is 115)

    I estimate that by September 7 the Atlantic ACE is normally about 40% complete, East Pacific is maybe 65% complete and the West Pacific is maybe 50% complete. If those hold true in 2007, then

    Atlantic for 2007 = 130
    East Pacific = 60
    West Pacific = 220
    Total = 410
    Normal = 515
    Northern Hemisphere = below normal

  17. SteveSadlov
    Posted Sep 6, 2007 at 6:54 PM | Permalink

    http://www.accuweather.com/news-blogs.asp?partner=accuweather&traveler=0&blog=yeager

    I had mentioned that there would be a large dip likely in the jet stream. According to the above interpretation, that dip will end up a bit East of what I’d initially thought. It will be interesting to see if this little kink in the works has an impact on the number of named storms, bogus or real.

  18. David Smith
    Posted Sep 6, 2007 at 7:04 PM | Permalink

    Steve S, a small piece of Felix entered the extreme southern Gulf this afternoon and shows signs of rotation. If by chance it regenerates then it may get a new name and thus Felix will count twice (Felix and Felix Junior) in the seasonal storm count.

    In fact, if Felix regenerates after struggling through the Central American mountains then it deserves bonus names :)

  19. steven mosher
    Posted Sep 6, 2007 at 7:30 PM | Permalink

    re19

    felix the cat and felix the mouse.

  20. SteveSadlov
    Posted Sep 7, 2007 at 9:31 AM | Permalink

    Assuming the increasingly agreed forecasts come to fruition ….. The Siberia Express, east of the Rockies version, one of the earliest manifestations I’ve ever witnessed:

    This has major implications for conditions throughout the Boreal portion of the Western Hemisphere.

  21. Don Keiller
    Posted Sep 7, 2007 at 1:23 PM | Permalink

    #20 “Siberia Express”???

  22. SteveSadlov
    Posted Sep 7, 2007 at 2:03 PM | Permalink

    RE: #21 – When the Jet Stream is oriented from the Arctic, near the International Date Line, down to points well in the mid latitudes, particularly, points in the Western US, and, in some cases, is actually flowing from just east of north, to just west of south, way down toward the bottom of the dip, that is referred to as a Siberia Express. It’s like an Alberta clipper, but more verticle and in most cases with that slight retrograde I described. Siberia Express brings Cold Fronts straight down from the high Arctic.

  23. SteveSadlov
    Posted Sep 7, 2007 at 3:50 PM | Permalink

    The NHC continues to string along some sort of hope that maybe-maybe-not-Gabrielle comes to fruition from the cut off low off the the East Coast. Yet another hurricane hunter visit (what was its carbon footprint?) and lo and behold, still an amorphous blob with a few thunderstorms here and there. The “hope” of the count padders would be that the ridge that is diagonal up from the SE will remain in place long enough to steer the thing over the Gulf Stream. It’s a race against the clock ….. the High will eventually start to move, the Gulf Stream is now cooling by the day, and, that big disruption in the Jet Stream is about to unleash climatic Fall across certain portions of the NH that are not already experiencing it. There is a reason that some of the tracks of the Low (a minority to be sure, but they exist) take it straight back up into the main stream flow and merge it with a cold front before it can, as they say, “go tropical.” What a complete farce.

  24. steven mosher
    Posted Sep 7, 2007 at 7:13 PM | Permalink

    SteveS,

    You realize that if you are right the AGW theory will be

    Fewer but Stronger storms

    I am writing the press release. Edits welcmed.

    “2007 brought clear indications that Global warming is affecting climate extremes.
    In a year where 15 Storms were expected, only 10 materialized, and 8 of those 10
    storms would have gone largely unnoticed and uncounted in years gone by. However,
    two storms, Dean and Felix, established an unprecidented record. The first two Hurricanes
    were both Category 5, defying the history books and deflating the skeptics of climate change.
    Gavin Schmidt of Nasa Goddard explained. “The science told us that Global warming would
    influence Hurricanes going forward and now we have a good understanding of what to expect.
    We can expect the unexpected. “

  25. SteveSadlov
    Posted Sep 7, 2007 at 7:36 PM | Permalink

    RE: #24 – also need to mention something like:

    “Furthermore, there is a growing body of evidence that cyclonic features of non tropical origin are demonstrating genesis into tropical forms with increasing frequency, possibly driven by a steady increase in global and particularly Atlantic Basis SSTs, as a result of GHG forcing.”

    LOL!

  26. SteveSadlov
    Posted Sep 7, 2007 at 7:37 PM | Permalink

    Argh…. “Atlantic Basin” …. solder a nice big ole honkin TDK bead on me bro …. ;)

  27. SteveSadlov
    Posted Sep 7, 2007 at 8:30 PM | Permalink

    http://www.nhc.noaa.gov/text/refresh/MIATCMAT4+shtml/080230.shtml

    They were ever so determined to name this feature.

    I wonder who will use it in their count?

  28. SteveSadlov
    Posted Sep 7, 2007 at 8:33 PM | Permalink

    This is what they named:

    No, it’s not April 1.

  29. David Smith
    Posted Sep 7, 2007 at 8:39 PM | Permalink

    A friend in a government agency told me that global warming in Hurricane Felix was so bad that the darn eyewall was on fire .

    I immediately suspected Photoshop but then he told me the photo had been peer-reviewed by climate scientists. Who am I to argue with that?

  30. David Smith
    Posted Sep 7, 2007 at 9:04 PM | Permalink

    Re #27 Gabrielle is classified as subtropical, so it should not count in any tropical analysis unless it transforms. Time is short for that.

  31. Kenneth Fritsch
    Posted Sep 7, 2007 at 9:14 PM | Permalink

    Re: #24

    Steven Mosher that was a very good press release and now I shall expect the unexpected. I would only add:

    “An additional nail or two was added to the coffin of the skeptics of anthropological global warming by the EUROSIP ensemble of climate models, which by primarily utilizing long term predictions of sea surface temperature anomalies and nearly exact locations of these anomalies, was able to disclose after the storm season ended that they were able to forecast the exact number of named storms and determine a probability of 52.53% that we would have at least two category 5 hurricanes.”

    “An interesting side note to the EUROSIP successes was witnessed at a recent Georgia Tech football contest where a professor, dressed in a cheerleading outfit as part of a global warming awareness half time celebration, lead cheers for the victory of the dynamical models over their old rivals the statistical-empirical models. The anonymously dressed cheerleader was heard to say after her cheer that the dynamical models performed wonderfully and got all the storm names correct.”

  32. SteveSadlov
    Posted Sep 7, 2007 at 9:24 PM | Permalink

    RE: #31 – Yer bad! ;)

  33. David Smith
    Posted Sep 8, 2007 at 12:33 PM | Permalink

    Here’s a slightly different view of the to-date hurricane seasons (Atlantic and East Pacific):

    For the Atlantic, a marked-up climatological graph is here . The heavy red line denotes September 8 (today) while the light red lines simply show the climatological averages of named storms, hurricanes and major hurricanes by this date.

    The box at the left shows the 2007 to-date numbers. This Atlantic season is looking near-normal so far.

    The same type of plot is offered for the East Pacific here . This has been a markedly below-normal season for the Eastern Pacific. That would be expected in a La Nina year, but 2007 has been mostly ENSO-neutral.

    In the Atlantic September 10 is the climatological peak of the season. At this point in a typical season certain things ( shear, stability) have already crested at their peak values and are beginning to move in directions unfavorable for storms. Things typically begin to wind down rather sharply over the next three or four weeks.

  34. K
    Posted Sep 8, 2007 at 5:13 PM | Permalink

    GABRIELLE is now labeled a tropical storm rather than a sub-tropical. The NHC advisory #4 doing that seemed a bit forced in wording. But when I looked over the satellite images GABRIELLE did show the rotation and form expected.

    To a layman the notion of a storm transforming into tropical when it is far from the tropics is a little unsettling. But I guess it is like those ‘life’ sentences where the guy gets out after seven years or so.

  35. Kenneth Fritsch
    Posted Sep 8, 2007 at 10:30 PM | Permalink

    I have been attempting to find the individual predictions of Meteo-France for 2007 as Judith Curry stated it was publicly available. I found one for the Met Office for 2007 which was 10 named storms on June 19, 2007 missing the 2 storms that had already occurred. I think Judith was confused between Meteo and Met.

    Meanwhile I am attempting to find the individual forecasts for the Meteo, Met and ECMWF for 1993 to 2007 and also determine how they decided to use those three sources for an average. In the GRL paper they coyly refer to Model1, Model 2 and Model 3 without using specific source names.

    They have a Model 1,2 and 3 and combined EUROSIP correlation of predicted and actual named NATL storms for comparison with the same correlations for TSR and CSU:

    Model 1 = 0.67; Model 2 = 0.78; Model 3 = 0.59; EUROSIP (combined Models 1, 2 and 3) = 0.81; TSR = 0.65; CSU = 0.39.

    In other words the averaged predictions gave a significantly higher correlation than did any of the individual models and selecting which models to average becomes an important issue. Does any of this bother anyone here?

  36. David Smith
    Posted Sep 9, 2007 at 8:12 AM | Permalink

    I think she meant UK Met Office.

    The EUROSIP approach appears to be like the short-term hurricane forecasters’ “ensemble” approach. In that approach the average of the projections from multiple models tends to give a better path forecast than any individual model.

    The EUROSIP approach, as I understand it, is to take the projections from an individual model and then determine a coefficient which makes that projection come close to reality. For instance, the model may project 30 storms whereas reality is 15 storms, so they multiply the projection by 0.5 to come close to reality.

    They used three models and twelve years to determine the coefficients which gave the best fit with the actual storm counts. Looks like a basic linear algebra exercise.

    The interesting part will be its performance when it is tested against out of sample years, such as 2005 and 2006 and beyond. Coefficients that fit well for 1993-2004 may not fit so well beyond 2004. We’ll see.

    Kenneth, on a different subject, if you’ll send to me your e-mail address I’ll send to you a nice article on your question about tropospheric temperature profiles versus the GCMs. My address is mndsmith33 AT earthlink.net

  37. RomanM
    Posted Sep 9, 2007 at 8:25 AM | Permalink

    Kenneth, I am bothered, but not surprised.

    In #464 (URL is http://www.climateaudit.org/?p=1082#comment-133541 , but for some reason, I couldn’t create the direct link to it) on the predecessor thread, Atlantic Hurricane Track Versions, Judith Curry gives a link to a paper (actually, a powerpoint) on multi-model forecasts. What caught my eye were the parts which said:

    ƒÝ We do not expect errors to be orthogonal or independent

    ƒÝ But at least some part of model error will differ and can be averaged out
    ƒÝ In general, expect ¡§ensemble mean¡¨ of forecasts to improve

    and

    We expect all models to be wrong, none of them to be possible solutions

    ƒÝ ARE sampling model-induced errors in predicted outcomes of individual events

    ƒÝ If these errors are independent, then a large multi-model ensemble might
    have a small error in the ensemble mean, much smaller than the intermodel spread

    -> Optimistic view of multi-model forecasts

    It is another example of the “use” of statistics involving models in climate science. The IPCC combine models on climate change in this manner without blinking an eye, presumably on the same principle expressed in the quotes: if you form enough incorrect models, you can average out the incorrectness and get the correct result! Perhaps if they understood the difference between the concepts of “independence” and “unbiasedness”, they could avoid such blatantly ridiculous statements. Presumably, this method would also work if you rolled enough dice with prediction numbers on them as well. Unfortunately, whether the averaged result will be close to reality or not is just a matter of pure chance having nothing to do with the combining procedures or the model reliability. By the way, how to choose the best way to combine the predictions is simplified by doing it after the actual results are known.

  38. RomanM
    Posted Sep 9, 2007 at 8:32 AM | Permalink

    That’s curious, I just typed the first URL as text in the previous comment and CA flagged it as a URL. Every time I had used the link tags myself, it wiped out all the text from that point to the second link in the post. What gives?

  39. Kenneth Fritsch
    Posted Sep 9, 2007 at 9:17 AM | Permalink

    Re: #36

    They used three models and twelve years to determine the coefficients which gave the best fit with the actual storm counts. Looks like a basic linear algebra exercise.

    That was my take also and it takes the forecasts out of the realm of a model looking dynamically at the laws of physics and into realm of statistical-empirical models that need to be tested out-of-sample. I find what they do coy at best and misleading at worst.

    While Judith Curry has great expectations for these models they cannot even predict storm strengths – and no prediction when they will have that capability. The claim is that what they have accomplished has come out of the climate model serendipitously and there has been no major effort to specifically forecast tropical storms. I get the view that the models need some outside help in actually “visualizing” tropical storms. I would like to dig deeper to see what really is being done.

  40. Judith Curry
    Posted Sep 9, 2007 at 9:19 AM | Permalink

    Yes, I meant UK Met Office (not meteo france, a brain typo). How to effectively combine ensembles (from a single model and multiple models) into a probabilistic forecast that accounts for all the issues raised in that ppt file previously referred to, is an area of active research. Climate models for the IPCC have just begun doing ensemble runs, and not so many ensembles at that (since each simulation takes so long to run.) more sophistication in interpreting these simulations is certainly possible and obviously desired.

  41. tetris
    Posted Sep 9, 2007 at 12:39 PM | Permalink

    Re: 34
    The “AGW-causes-more/stronger-hurricanes” crowd need to up the 2007 numbers so badly that if GABRIELLE had somehow geared up in Boston harbour it would still be counted as a TS.

  42. RomanM
    Posted Sep 9, 2007 at 12:51 PM | Permalink

    #40 Dr. Curry.

    I appreciate that research in the area needs to be and is being done. However, what I read in the powerpoint seems to indicate a certain naivety concerning the appropriate use of statistics in the current interpretation of models.

    In mainstream statistical methodology, statistics can be used to summarize and interpret results when there is a random component to a model. The random elements are part of the model itself and their stochastic characteristics are well-defined. For example, cloud coverage, wind movements, jet stream variations could be such factors. In that case, it is reasonable to do ensembles of runs (in the hundreds of repetitons) and to use statistical evaluations and use probabilitistic language when stating results. IF the model is well constructed and the factors appropriately defined in the model, the results will have some credibility.

    The situation is quite different when the model is deterministic. I have seen papers where the runs consisted of varying a given parameter whose value is unknown over a wide range of possibilities and where the results were averaged to give the “best estimate”. No amount of statistical arm waving provides a reasonable justification for the stated results. Even in those cases where Bayesian mathods are used, there still needs to be a convincing argument for the choice of the particular prior distribution and in many cases, the choice is made on the basis that you can theoretically do the math with that particular prior.

    Here, we seem to be looking at a third scenario – multiple models which appear to be based on different assumptions about the choice of and the various relationships among the factors involved. Whether the models are deterministic or stochastic, the intent is to somehow combine the results into a single prediction, usually by giving equal weight to all of the models. There is always a tacit assumption that somehow the error of the combined result will be “much smaller than the intermodel spread”, a spread which might well exist because of inadequacies in some of the models themselves. Many examples of this type of abuse of statistical methods exist in the latest IPCC report. The researchers could benefit from looking at some techniques for first evaluating how good each particular model might be before deciding how to combine them. I have seen some papers on incorporating “expert opinion” into statistical analyses. This could be helpful to the modellers (with the role of “expert” played by the model) in deciding how well each model can do its job.

    As an aside, I have a question. How many of the models (for hurricanes and climate, in general), if any, actually mirror the world by including geographic world features?

  43. Judith Curry
    Posted Sep 9, 2007 at 1:35 PM | Permalink

    Two comments:

    The “AGW causes more hurricanes crowd” are definitely not the people in charge of naming storms. The people in charge of naming storms are the people at the national hurricane center, includes “AGW doesn’t cause more hurricanes crowd” stalwarts such as landsea and goldenberg who are distinctly on the other side of this debate. So the national hurricane center is pretty conservative in this regard, they are not looking to inflate the numbers. Scientists (even the AGW-hurricane crowd) aren’t looking to inflate the numbers either, we’re just trying to figure out what is going on.

    The other point is with regards to how to “weight” the ensembles and different models are combined to provide a forecast. One of the key points of the ppt presentation is that historical error statistics can be used to identify which model tends to do better overall and for various situations, and you can use this information in putting together a probabilistic forecast using the ensembles. This is simpler to do for the hurricane type forecast (for which you have lots of error statistics) vs the global warming scenario (for which you don’ have verification statistics).

  44. fFreddy
    Posted Sep 9, 2007 at 1:38 PM | Permalink

    Re #42, RomanM

    There is always a tacit assumption that somehow the error of the combined result will be “much smaller than the intermodel spread”

    Of course. Haven’t you heard of the Central Limit Theorem ?

    /sarcasm

  45. RomanM
    Posted Sep 9, 2007 at 2:09 PM | Permalink

    #43

    The (serious) suggestion that I offered in #42 as a possible approach for combining models was in reaction to statements from the ppt like

    Deriving weights for model combination

    Not all models are created equal
    We believe some models perform better in some regions, less well in
    others
    Stable calculation of “optimal” weights based on past performance is
    problematic, especially as number of models increases
    Presently, ad hoc methods are used eg at IRI
    Ideally, want a justifiable and stable method which properly accounts both
    for past experience and the sampling uncertainties in that experience
    Alternatively …. Just take a simple mean
    Averaging the ensemble mean and averaging probabilities are different

    They use ad hoc methods, simple means, averaging probabilities… and from these we are supposed to get a sense of “sampling uncertainty”? As well, elsewhere, it says

    More models are better (not just few best ones)
    More models gives bigger gain than bigger ensemble size

    Not only does this lead to underestimation of error bounds, but there is also evidence that it may lead to a deterioration of the estimates and predictions themselves. More is not always better! What is better is a method based on sound theory.

  46. RomanM
    Posted Sep 9, 2007 at 2:30 PM | Permalink

    #44 fFred

    You’ve got the wrong theorem here. What they are using is a new version of the Law of Large Numbers (sometimes popularly called the Law of Averages). Besides the Weak LLN and the Strong LLN, we now have the Really Strong LLN:

    “If you collect a whole lot of numbers (no matter from where or what kind), your result will be as close as you want to whatever it is that you want it to be close to”.
    :) (How do you get those yellow smiley faces to appear?)

  47. David Smith
    Posted Sep 9, 2007 at 2:38 PM | Permalink

    If the NHC is erring on the side of naming too many storms I suspect it has to do with proximity to land (they are being cautious) and to what I call the Weather Channel Effect, wherein 20 million viewers in the US get excited any time they see a swirl and call/write the NHC.

  48. tetris
    Posted Sep 9, 2007 at 3:13 PM | Permalink

    Re 43

    Landsea and Goldenberg presence notwithstanding, with the NHC naming GABRIELLE we now have a 2007 record which will wind up showing at least two [and arguably three] “storms” that should simply never have been named for failing to meet basic criteria.
    Take those questionable storms out of the tally and you have a pretty slow season, indeed. Even with Dean and Felix NA ACE numbers are quite low. All in all not very supportive of the contention that AGW causes more/stronger hurricanes.

    Re: 47
    I agree with you that the Weather Channel Effect is quite real. The problem here is that organizations like the Weather Channel [and their counterparts in both North America and Europe] have a vested business interest in sensationalizing things. We all know that watching paint dry doesn’t sell copy or improve ratings, but it is precisely in that context one would expect an organization like the NHC to serve as a voice of professional moderation.

  49. fFreddy
    Posted Sep 9, 2007 at 4:06 PM | Permalink

    Re #46, RomanM
    Heh – don’t be fussy – this is climatology (rhymes with numerology …)

  50. Philip Mulholland
    Posted Sep 9, 2007 at 4:13 PM | Permalink

    Re 43, 47 & 48

    Guys

    If you think the call for this year’s tally is bad, try looking at 2005.
    Hurricane Vince was a joke.

    http://www.nhc.noaa.gov/pdf/TCR-AL242005_Vince.pdf

  51. steven mosher
    Posted Sep 9, 2007 at 4:28 PM | Permalink

    RE 48.

    I hope they inflate the number of storms, especially those that do no
    damage. It messes with anyone’s ability to confidently predict the future
    and I like suprises, except the squishy kind of suprises that show up between
    your toes when you walk in the yard and the kids forgot their dog chores.

  52. Kenneth Fritsch
    Posted Sep 9, 2007 at 7:35 PM | Permalink

    Re: #43

    The “AGW causes more hurricanes crowd” are definitely not the people in charge of naming storms. The people in charge of naming storms are the people at the national hurricane center, includes “AGW doesn’t cause more hurricanes crowd” stalwarts such as landsea and goldenberg who are distinctly on the other side of this debate.

    The statistical-empirical crowd may have gone long this year while the dynamical camp may be going short with their forecasts for named storms. If the statistical-empirical crowd is in charge of the naming then they might be accused of naming inflation. Since my forecast is long I say “name it and claim it”.

    Seriously I think if one looks very closely at how the naming system is being used one has to strongly consider other measures for tracking issues such as AGW and storm frequency. There appears to me that there is good evidence that the historical records of named storms into even recent times are significantly affected by an ever increasing capability to detect these storms and now we have naming inflation. For many reason these changes have occurred, but mostly because of increasingly better technology combined with a sincere effort to establish warnings for coastal residents. As long as scientists do not abuse these changes by appearing innocently not to acknowledge them in support of a favored theory, I would think that data could be used for warning and science.

  53. BarryW
    Posted Sep 9, 2007 at 7:51 PM | Permalink

    Given the winds and track of GABRIELLE would it have been classified as a TS in the 1900 to 1940 time frame (prior to sattelites and storm hunter planes)?

  54. David Smith
    Posted Sep 9, 2007 at 8:10 PM | Permalink

    Re 53 Clearly no.

    Indications are that, in the 1930s for example, the analysts looked for windspeed, a low barometer and several other supporting factors like windshifts, temperatures, location and a correlation of highest wind with lowest barometer.

    An illustration of the difficult position of 1930s meteorologists can be found here in the September 1933 listing of “North Atlantic Gales and Storms” for that single month. Imagine trying to determine which gales were of weak tropical storms versus subtropical, upper level lows, strong tropical waves, etc, especially in the early or late parts of a season and in the remote regions.

  55. David Smith
    Posted Sep 9, 2007 at 8:16 PM | Permalink

    Re #54 I forgot to mention Gabrielle. With a 29.74 barometer, a small area of gale winds away from the center and a subtropical origin, Gabrielle would fall into the “probably not a tropical storm” category. Since it passed over land, though, a weatherman might piece together the track as shown by surface station barometers and make an argument for inclusion, but he’d have to be persuasive.

  56. Posted Sep 10, 2007 at 5:50 AM | Permalink

    Remember, you should never overstate the impact of uncertainties,

    We caution, however, that researchers should not overstate the impact of existing uncertainties on our ability to discern certain key long-term trends in tropical cyclone activity.

    Mann et al, Atlantic Tropical Cyclones Revisited

    See also Sabbatelli et al., The Influence of Climate State Variables on Atlantic Tropical Cyclone Occurrence Rates, Poisson Regression etc. interesting stuff there.

    ( http://www.meteo.psu.edu/~mann/Mann/articles/articles.html )

  57. David Smith
    Posted Sep 10, 2007 at 8:53 AM | Permalink

    Re #56 Wow: to paraphrase, “never let poor-quality data stand in the way of a bold conclusion”.

  58. Larry
    Posted Sep 10, 2007 at 9:01 AM | Permalink

    This just in:

    http://www.bloomberg.com/apps/news?pid=20601103&sid=aWuWjvhiv8Y4&refer=us

    Hurricane Scientists Flubbed Forecasts for Two Years

  59. SteveSadlov
    Posted Sep 10, 2007 at 10:21 AM | Permalink

    RE: #55 – Out West, it would have been just another cut off low.

  60. SteveSadlov
    Posted Sep 10, 2007 at 11:48 AM | Permalink

    http://www.accuweather.com/news-blogs.asp?partner=accuweather&traveler=0&blog=community

    Hahahahaha!

    What a joke. And now, that Siberia Express is fully in place. Cold fronts will shortly be lined up from the Chukchi Sea to the Bahamas. Fall is here. Put a fork in it, this season is now on its steep downhill decline.

  61. Kenneth Fritsch
    Posted Sep 10, 2007 at 11:52 AM | Permalink

    Re: #56

    Remember, you should never overstate the impact of uncertainties,

    I am not a professional researcher at this point in my life, but I ask forgiveness for a proclivity to appear as someone with too much concern with uncertainties and the impacts of them. I do not judge that I overstate them but that probably derives from my inability to see the bigger Mannian sized picture.

    The paper by Mann and Sabbatelli appears on first glance to follow the lines of analyses done at CA on conditioning data to fit a Poisson distribution. Willis E did an analysis removing a trend and cyclical components that produced an excellent fit to a Poisson distribution. I would prematurely suggest that one will find that Mann did essentially the same analysis but confounded, from my POV, an increasing capability over time to detect tropical storms with a trend in increasing SST.

  62. Kenneth Fritsch
    Posted Sep 10, 2007 at 6:06 PM | Permalink

    Re: #61

    The Mann and Sabbetelli paper, in this layperson’s estimation, does a proper statistical analysis but neatly avoids the issue of improving historical storm detection which in this case can easily be confounded with increasing SST over time. The authors use MDR SST, Nino3.4 and NAO as state variables (positive/negative and positive/neutral/negative) and do a generalized linear model regression assuming a state dependent Poisson distribution and calculate maximum likelihood values for the regression parameters of beta sub i. This statistical handling of the storm data can be done easily with R, I know, but I do not know R well enough to do it myself.

    The question with this analysis, as others with tropical storm data, boils down to the potential confliction of SST and increasing capabilities to detect tropical storms. The authors here refer, as Holland and Webster did in their recent paper, to passing ships of times past if not warned of storms will detect them. At the same time they note that a better model should include a factor for changes in historical detect capabilities, but for now they are content to say the data is unaffected by these capabilities.

  63. SteveSadlov
    Posted Sep 10, 2007 at 7:00 PM | Permalink

    RE: #62 – They completely miss the fact that the sheer numbers of ships on the sea at any given time have skyrocketed, especially since the advent of the lowly shipping container.

  64. Paul Linsay
    Posted Sep 10, 2007 at 9:17 PM | Permalink

    #61, Ken,

    I never got around to writing up the complete hurricane analysis but I think the trend idea is wrong, it’s just random fluctuations.

    The recent issue is the decade from 1995 to 2004 with 78 hurricanes. From the 156 year average one would expect 52.5 hurricanes during the decade. the Poisson probability of a particular decade having that many hurricanes or more is

    P(>=78;52.5) = 1.13 e-3

    There are 147 decades in the 156 years of data, hence one would expect to observe

    147*1.13 = 0.166 decades with at least 78 hurricanes. The probability of seeing at least one such decade in 156 years is thus

    1 – exp(-0.166) = 0.153

    For comparison the probability of throwing 6 with a pair of dice is 13.9% and 7, 16.7%.

    However, if you throw in the 15 hurricane year of 2005 the probability drops to 0.0082. A single 15 hurricane year by itself is not particularly improbable. Stochastic processes produce rare events, sometimes while you’re watching.

    The same analysis for the decade of 1905 to 1914 with only 32 observed hurricanes, this time for 32 or fewer hurricanes, gives a probability of 14.6%

  65. DeWitt Payne
    Posted Sep 10, 2007 at 11:06 PM | Permalink

    38

    Every time I had used the link tags myself, it wiped out all the text from that point to the second link in the post. What gives?

    The preview pane parses multiple links incorrectly. If you had posted the comment, it would probably have been correct with all links and text included. To see the text correctly in the preview pane, put a space after the = and before the “http… in every link tag. The links in the preview pane now won’t work, but you can read everything you wrote and the posted links will work, or at least they have for me.

  66. RomanM
    Posted Sep 11, 2007 at 6:57 AM | Permalink

    DeWitt, thanks for the explanation. I usually hesitate in posting something that doesn’t look right in the preview and instead try to reformat my text so that it previews OK. I was also surprised when the smiley face magically appeared in the post in #46 when the preview only showed the : and the ) that I had typed there. Mousing over the faces others had used seemed to indicate that this is also what they had typed as well. Live and learn…

  67. Kenneth Fritsch
    Posted Sep 11, 2007 at 9:43 AM | Permalink

    Re: #64

    I never got around to writing up the complete hurricane analysis but I think the trend idea is wrong, it’s just random fluctuations.

    Paul, you are talking about hurricane counts and the Mann and Sabbetelli paper is looking at named storms. When I analyzed named storms, hurricanes, major hurricanes and landfall events, I found that the trends decreased (to essentially zero for landfall events) with the category by how easily one would expect the category to be detected. To me this makes a substantial case for the trends being primarily a manifestation of changing detection capabilities.

    Also I recall that the chi square test for goodness of fit to a Poisson distribution for named storms over the entire recorded history was very poor. Willis E. did an exercise in which he removed a cyclical component and trend from the data and I did a chi square goodness of fit for Poisson distribution on his adjusted data and found an excellent chi square fit.

    Now, the cyclical component in these storm counts is much less controversial than attempting to separate the effects of an historical upwardly trending SST that effectively matches an upwardly trending detection and measurement capability. There is apparently good agreement that a cyclical component to some extent is present in counts distributions due to the NAO and ENSO phenomena.

    The de-trending, as Willis E. did it, is a good start for looking at a better fit to a Poisson distribution. The second part of this effort is to determine the contributions of SST and detection/measurement capability improvements to the increasing trend line. I judge by the evidence I have seen that the contribution weighs heavily in favor of the improving detection capability.

    In Mann’s paper this second part is given short shrift when in my mind it should the most important part of his paper. The “ships passing storms” rationale for using unadjusted storm counts seems to have become a major reference in all papers purporting to show that SST has a major effect on tropical cyclone frequencies. After reading Mann’s paper a second time, I find Willis E’s analysis much more direct and easy to understand — although I must admit that for a Mann authored paper this one was much easier for me to comprehend than others. Maybe Sabbetelli wrote it.

  68. SteveSadlov
    Posted Sep 12, 2007 at 10:08 AM | Permalink

    So here’s a good one. Cut off extra tropical low poking around off of Texas. “Norther” Cold Front coming down from the northern plains. Jet stream in a big dip down over the southern plains. Oh I get it, because of the warm water in the Gulf this time of year, we call it a TROPICAL depression, out of force of habit. Yet another non ITCZ originated, extratropical feature, entered onto the naming roulette wheel:

    http://www.nhc.noaa.gov/refresh/graphics_at4+shtml/144527.shtml?3day#contents

  69. SteveSadlov
    Posted Sep 12, 2007 at 10:23 AM | Permalink

    Now this, on the other hand, is completely legit. Classic Eastern Wave / ITCZ descended feature, with a clear current track toward the westnorthwest:

    http://www.nhc.noaa.gov/refresh/graphics_at3+shtml/144024.shtml?5day#contents

    If I were in charge …. LOL …. here would have been this season’s named storms to date:

    1) Barry (a borderline case, but, I figure, what the heck ….this would have been my gimme, in exchange for not naming / counting the feature which was named Erin) – based on my counting criteria, of course, the orginal Andrea would not have been counted, so this would have been Andrea in my schema
    2) Dean – this would have been Barry in my schema
    3) Felix – this would have been Chantal in my schema

    The storms that were orginally named Andrea, Chantal, Erin, and Gabrielle, would not have been counted or named, if I ran the NHC.

    So, assuming that the above feature does reach storm-hood today, it would have been TS Dean with a decent chance to become Hurrican Dean. We’d now be at 3 named storms, approaching 4. That is how quiet it really is this year. BTW – at the risk of being an alarmist, I would say that if you live in Dover, Atlantic City or NYC, watch out! The changes in the jet stream now taking place may cause this to curve right into the coast somewhere between Ocean City and the Hamptons.

  70. Mike B
    Posted Sep 12, 2007 at 11:41 AM | Permalink

    Re#68 and #69

    And now *presto* you’ve got Humberto!

  71. Kenneth Fritsch
    Posted Sep 12, 2007 at 4:42 PM | Permalink

    Within a day or so I think us high flying storm counters will be naming and claiming two more storms for a total of nine. If we are ever more vigilant in finding the teeny storms will make our forecasted counts yet. As they say in baseball it will look like a line drive tomorrow or in some climate scientist’s future paper.

  72. David Smith
    Posted Sep 12, 2007 at 4:49 PM | Permalink

    I am about 70 miles from the center of Humberto, with the center expected to move over my community in about six to twelve hours. Current winds outside the house are a roaring 6 MPH, with gusts to 9.

    My expectation is that we’ll get some heavy rain and maybe 25-30MPH gusts at the worst.

    Humberto may end up as an indirect killer, however. The storm has gotten huge media hype locally and panicked some decision-makers into doing things like closing schools and businesses, which adds to the nuttiness. Then, when the storm proves to be a non-event as far as wind goes, people lose their concern and caution, so that when a bad one finally arrives it gets ignored by many. This is part of what happened in New Orleans.

    I may post “eyewitness reports” later this evening as Humberto moves overhead. This assumes that my current computer gremlins lessen (and that I survive the storm).

  73. SteveSadlov
    Posted Sep 12, 2007 at 5:44 PM | Permalink

    RE: #71 and 72 – Just as an exercise, as the Pacific / Aleutian storm season ramps up over the next few weeks, I am going to flip on my swirl detector. I will run a farsical yet telling exercise – a “what if” schema for hypernaming in the Pacific. Heck, with this, the season will last all year. When the traditional ITCZ storms which are birthed off of Central America and SW Mexico wind down, the extra tropical regime out here will start cracking. Then, in Spring, when the extra trops wind down, the East Pacific ones will be stepping up to the plate.

  74. Richard Brimage
    Posted Sep 12, 2007 at 7:08 PM | Permalink

    I checked the data bouy closest to Humberto (very close by the way) and the max winds had been in the 20 to 22 knot range.

  75. David Smith
    Posted Sep 12, 2007 at 7:11 PM | Permalink

    I’m now about 50 miles from the eye of Humberto. Ten minutes ago I actually witnessed leaves rustle in a tree, briefly. Winds are maybe 6 MPH.

  76. SteveSadlov
    Posted Sep 12, 2007 at 8:32 PM | Permalink

    RE: #75 – I was going to write, what you’ve got there is about as good as a run of the mill Pinnapple Express, but since I saw this post, now it’s a mere Channel Islands October Cut Off.

    Wouldn’t you agree that our ad hoc names out here in the land of Black Bart are a bit more colorful than dumb old given names of guys and gals?! … :)

  77. tetris
    Posted Sep 12, 2007 at 10:40 PM | Permalink

    Re: 75
    This naming business is becoming utterly rediculous.

  78. Gerhard H.W.
    Posted Sep 13, 2007 at 4:32 AM | Permalink

    Re: 77
    With more and more named Bogocanes the fraction of Cat4/5 Sorms is reduced.

  79. Gerhard H.W.
    Posted Sep 13, 2007 at 4:43 AM | Permalink

    Btw. if you are interested in sat-movies of hurricanes, take a look at the Austrian ZAMG Hurricanes Site

  80. Posted Sep 13, 2007 at 4:50 AM | Permalink

    Humberto swerved eastward away from my location so no reports from the eye.

    Since it passed through a region with buoys, oil rigs (=many local wind meters), Doppler radar, aircraft recon, a major port (= many ships) and five million people, the region of stronger winds, about 30 miles wide, was easily detected.

    Had this been 1940 in the same location, where detection capability was limited, I’d put the odds at 50-50. Had the location been Nicaragua instead of Texas, the odds would be considerably lower than that.

    Had this been 1900 the chances would be quite low.

  81. SteveSadlov
    Posted Sep 13, 2007 at 8:14 AM | Permalink

    Is this data manipulation?:

    http://www.nhc.noaa.gov/refresh/graphics_at4+shtml/085527.shtml?swath#contents

    A “hurricane” wind swath that small …. what, I suppose they threw together Dvorak imaging with a backyard anemometer?

  82. SteveSadlov
    Posted Sep 13, 2007 at 8:18 AM | Permalink

    Hard to tell now that it’s over land, but it would appear that the “eye” was probably post cold front subsidence:

    I am going to have to real fun here in a few weeks, naming with abandon. The first good tightly wound low with a leading cold front to come in here will be named …. by the National Hysteria Center (NHC)…. coming soon to a blog server near you! ;)

  83. SteveSadlov
    Posted Sep 13, 2007 at 8:28 AM | Permalink

    Yes, sad to say, the NHC really are that cynical:

    http://www.goes.noaa.gov/HURRLOOPS/gulfir.html

    They really did use an intense gust front of the developing cold front to claim that it became a “hurricane.” In this IR image, you can clearly see that just as the so called “TD” became a so called “TS” what really happened was that the cut off low got sucked into an system of polar origin (Cold Front) that came down along the High Plains early this week. As that happened, the system was sheared into two major blobs, and transformed into a typical mid latitude cyclone of the type that is strung in series along a major front. As this occurred, polar air moved in from the NNW, and a massive squall line / cold front formed out of the eastern portion of the storm. Those winds were what were used to say “we have reached hurricane force.” This is comical.

  84. SteveSadlov
    Posted Sep 13, 2007 at 8:32 AM | Permalink

    Actually, what they used were winds at the center of the closed, tepid/cold core low. There was no eye at all. We have probably had at least a couple dozen storms like this on the West Coast over the past 5 years.

  85. SteveSadlov
    Posted Sep 13, 2007 at 8:35 AM | Permalink

    A “northercane!” ….. Bwahahahaha!

  86. SteveSadlov
    Posted Sep 13, 2007 at 8:50 AM | Permalink

    Yep, looks like temps are all colder than normal in most southeastern and northestern districts in Texas. 60s and 70s vs the normal 80s and 90s which would be more typical of mid Sept.

  87. Posted Sep 13, 2007 at 10:28 AM | Permalink

    from NHC: “BASED ON OPERATIONAL ESTIMATES…HUMBERTO STRENGTHENED FROM A 30 KT
    DEPRESSION AT 15Z YESTERDAY TO A 75 KT HURRICANE AT 09Z THIS
    MORNING…AN INCREASE OF 45 KT IN 18 HOURS. TO PUT THIS
    DEVELOPMENT IN PERSPECTIVE…NO TROPICAL CYCLONE IN THE HISTORICAL
    RECORD HAS EVER REACHED THIS INTENSITY AT A FASTER RATE NEAR
    LANDFALL. IT WOULD BE NICE TO KNOW…SOMEDAY…WHY THIS HAPPENED.”

  88. Joey
    Posted Sep 13, 2007 at 10:44 AM | Permalink

    Steve,

    I am a lurker here because I have no technical knowledge or experience like the rest of you. However, I lived in Oklahoma for close to 10 years and watched weather all my life wherever I lived. 60 mph winds are not unusual (relatively speaking, usually they are straight line winds) for that region. I find it silly to say a storm is a hurricane simply because a certain wind speed is met for a short period of time,ESPECIALLY DURING THE APPROACH OF A STRONG COLD FRONT AT THIS TIME OF YEAR.

    I love your comments, by the way.

    Regards,
    Joey (returning to lurk status)

  89. SteveSadlov
    Posted Sep 13, 2007 at 11:03 AM | Permalink

    From the way the cells blossom on the IR loop, it’s fairly clear that some pretty cold air started overriding.

  90. STAFFAN LINDSTROEM
    Posted Sep 13, 2007 at 5:42 PM | Permalink

    89 Steve S to get another laugh watch the WC report
    with the guy with the hand in front of his head because
    the rain is so HARD(so called TH Humberto), (unfortunately I can’t save it easily
    they’ve changed from Real to Flash format) then go to You
    Tube and compare WC report 1992 from Andrew…Cat 5…The
    Weather Channel has turned into a pathetic story with
    Heidi Cullen & Co…

  91. SteveSadlov
    Posted Sep 13, 2007 at 6:15 PM | Permalink

    Check out the overall circulation now. (e.g. using the IR loop).

  92. steven mosher
    Posted Sep 13, 2007 at 7:13 PM | Permalink

    87.

    AGW theory 10.2.

    Global warming may increase the number of TS, and or the number of hurricanes,
    and/or the number of strong hurricanes, and/or the number of landfalling hurricanes,
    and/or the early appearence of cat 5s, and/or the appearence of sequential cat 5s,
    and/or the rapid transfrmation of TSs into hurricanes.

  93. SteveSadlov
    Posted Sep 13, 2007 at 9:22 PM | Permalink

    and/or wanting to name a really bad squall line as a hurricane …..

  94. SteveSadlov
    Posted Sep 13, 2007 at 9:57 PM | Permalink

    Just sort of messing around with this at this point. I’m sure you can imagine what will become of this once the Gulf of Alaska and the area just to the north of Hawaii start cracking a few weeks from now:

    http://nationalhysteriacenter.blogspot.com/

    Strictly for entertainment purposes ….. :)

  95. Bob Koss
    Posted Sep 14, 2007 at 12:28 AM | Permalink

    reid simpson,
    Re: #87

    The NHC is certainly putting out a crock with that intensity BS.

    Normally they use 6 hour increments at 0Z-06Z-12Z-18Z. 15Z and 09Z aren’t standard recording times. No shame I guess. On top of that they are still wrong.

    HATTIE shown below eventually reached Cat 5 and went from 45 knots to 100 knots within 18 hours of first observation. Also started out 6 miles closer to land. Standard time frames are used.
    Id# Year Month Day Qtr. Stage Lat. Lon. Wind Bars Landfall
    875 1961 10 27 3 * 11.6 -81.5 45 NA 57
    875 1961 10 27 4 * 12 -81.6 55 NA 32
    875 1961 10 28 1 * 12.8 -81.7 65 991 6
    875 1961 10 28 2 * 12.9 -81.7 100 NA 12

  96. fFreddy
    Posted Sep 14, 2007 at 1:38 AM | Permalink

    Re #94, Steve Sadlov

    Steve, have you considered doing that blog as a serious analysis of why hysterical outpourings and namings from the NHC are wrong ? Cast it at a level that would be scientifically correct but comprehensible to an intelligent layman ?

    It strikes me it could be a useful resource for one of the dwindling supply of honest journalists out there. One suspects that the only thing that is going to get the NHC back to behaving sensibly is bad press about their current behaviour. You obviously have the expertise to dissect their current behaviour; if you were to put it in one easily-referenced place – rather than scattered throughout the comments section here – it could provide a journalist with what they need to start making a stink.

    (Please continue with the comments here – they are very educational !)

  97. Posted Sep 14, 2007 at 4:57 AM | Permalink

    Re #95 Good catch, Bob.

    I watched the Humberto seedling for three or four days before it became a depression/storm. The seedling had a well-defined structure in the middle and especially upper troposphere a day or two before it became a surface storm, so it had a head start on the strengthening process. The seedling’s low-level circulation was also underway early, but was spread along an axis (in other words, it wasn’t concentrated or focused). The low level finally concentrated Tuesday night and the strengthened process was underway at an accelerated rate.

  98. Judith Curry
    Posted Sep 14, 2007 at 5:44 AM | Permalink

    Re “naming hurricanes”, check out this article

    http://www.theonion.com/content/news/nameless_hurricane_that_much_more

  99. STAFFAN LINDSTROEM
    Posted Sep 14, 2007 at 7:18 AM | Permalink

    #95 Bob…Hattie a appropiate name for us Swedes..
    To “hatta” means to go from one place to another quickly
    and irrationally…
    Hattie is the only “Slalom Hurricane” my copyright
    please or…Hattie aka Simone in the Pacific aka Inga
    back in the Gulf…Well Wikipedia credits…

  100. STAFFAN LINDSTROEM
    Posted Sep 14, 2007 at 7:40 AM | Permalink

    #94 Impressive Steve S …NHC is also, referring to my
    earlier post(#90) comparing TWC 2007 and 1992, a quite
    common abbreviation for “Nitty Heidi Cullen”… BTW
    Steve Mosher got post 666 in unthreaded # 19, I’ve always
    suspected the Devil is only playing golf during TS/TH… BTW
    # 2 …Golfwise Solheim Cup can get some nasty weather down
    in Halland…And congrats all US if you’re interested in
    soccer…2-0…
    #99 for myself…Inga Lindström is the “heroine” …well
    leading role of a very popular German series taking place
    in Sweden…

  101. beng
    Posted Sep 14, 2007 at 7:44 AM | Permalink

    Hurricane Felix & this thread brought to mind (but I have to give credit
    to the old Captain Kangeroo Show):

    Felix the storm-counters,
    the wonderful, wonderful storm-counters.
    Whenever they get in a fix,
    they reach into their bag of tricks.
    :)

  102. RomanM
    Posted Sep 14, 2007 at 7:46 AM | Permalink

    #98

    Thanks for the morning chuckle – it was an incisive jab at the way the national mass news media has been exagerating events and creating public perceptions and unwarranted hysteria. Good web site.

    However, the issues raised in this thread about the reasonableness of the categorization and naming procedures this year still stand. NHC appears to be overstating the case recently and “adjusting” the counts to match those predicted by the GCMs. By seemingly lowering the boundaries for category levels, they will certainly make it more difficult to make valid comparisons with counts of hurricane activity in the past.

  103. David Smith
    Posted Sep 14, 2007 at 7:47 AM | Permalink

    The models show westerly high-level winds spreading across the tropical Atlantic the next week or two. Those tend to suppress both the number and intensity of storms. Since this is the heart of the season that’s almost a final nail in the coffin of any thoughts that 2007 will prove to be hyperactive.

  104. John Goetz
    Posted Sep 14, 2007 at 7:50 AM | Permalink

    Steve S.

    Love your analysis. Of course, there are others who disagree and believe Humberto’s elevation to category 1 is a sign of a different sort of continuing, worrying trend :-)
    http://rabett.blogspot.com/2007/09/there-is-nothing-new-in-gulf-eli.html

  105. steven mosher
    Posted Sep 14, 2007 at 10:06 AM | Permalink

    RE 100.

    Humberto was golfable if you know how to hit a proper punch shot, but don’t
    count on breaking the course record, see Caddy Shack.

    My grandmother Johnsen was 100% swede and Lasse Halstrom’s “My Life as a Dog”
    is the best movie ever, So I can’t be the devil.

  106. steven mosher
    Posted Sep 14, 2007 at 10:20 AM | Permalink

    RE 102

    Roman I agree 100%. Fiddling with the numbers is a short term play for gain but a long term mistake

    Dr. Curry should concur ( i like the sound of that )

    Seems to me we have the equivalent of grade inflation. I have no issue with subjective assesments made
    by professionals who have been properly trained and “normed” in the evaluation process, but do these
    folks go through a norming process?

  107. Kenneth Fritsch
    Posted Sep 14, 2007 at 10:46 AM | Permalink

    Re: #103

    The models show westerly high-level winds spreading across the tropical Atlantic the next week or two. Those tend to suppress both the number and intensity of storms. Since this is the heart of the season that’s almost a final nail in the coffin of any thoughts that 2007 will prove to be hyperactive.

    David, shame on you for taking some of the excitement out of you own forecasting contest. We have named and claimed 9 NATL tropical storms thus far and it has been a struggle all the way. Could it be that your claim is for a naming system of a bygone era and if we work really hard and diligently search we will find more storms under these less than favorable conditions?

    I did my back-of-the-envelope calculation from my historical records of the portion of named NATL storms occurring by month and it puts me on track to fulfill my forecast very close to spot on. I was feeling quite good about this (the forecast and not the potential damage – I am hoping for weak harmless storms to increase the count) and then I had to read your post.

    I read the Judith Curry linked humorous article about unnamed hurricanes scaring the bejibbers out of coastal residences and the need to have names that will sooth the residents with the familiar and something to which they can relate. This article probably put this issue in good context, i.e. the naming system is not being used for the purpose of a scientific/statistical comparison and though it may have been more so that way in the past, we have agreed to a large extent here that the detection and measuring capabilities have increased and can be a major factor in the increasing trend of named storm numbers.

    By the way, I find the recently linked Mann and Sabbetelli paper on using a state variable influenced Poisson distribution for forecasting named storms of interest in that they are strong AGW adherents who are using and apparently advocating the use of empirical/statistical modeling over dynamical modeling.

  108. steven mosher
    Posted Sep 14, 2007 at 11:08 AM | Permalink

    My male Hurricane names:

    Andy,Bruce,Chas,Dilbert,Eddie,Francis,Gavin, Humbert,Joey,Kip,Lance,Nicky,Opie,Percy….

  109. Posted Sep 14, 2007 at 11:17 AM | Permalink

    Re #98

    Some storm names sound ferocious (Ivan, for example) while other possibilities would gain little respect. For example,

    Dee-dee
    Chuck
    Bud
    Dot
    Pancho
    Nimrod
    Bubba

    I remember Hurricane Bob. It was hard to be worried about something named Bob even though it passed within 50 miles of my house. The same would hold true for Hurricane Bubba or Typhoon Chuck.

  110. Posted Sep 14, 2007 at 11:21 AM | Permalink

    Perhaps we should also use selected surnames, too.

    I bet the name “Hurricane McIntyre” would make some nervous.

  111. Michael Jankowski
    Posted Sep 14, 2007 at 11:21 AM | Permalink

    re#107

    in that they are strong AGW adherents who are using and apparently advocating the use of empirical/statistical modeling over dynamical modeling

    Truly interesting considering “I am not a statistician” Mann is involved. But that hasn’t kept him from statistical work before.

    One problem with dynamical modeling for AGW adherents is the recent observation that increased wind shear due to global warming could weaken hurricanes.

    One huge advantage with empirical/statistical modeling when it comes to AGW adherents is the convenience of how hurricane records are spotty prior to the modern area, which makes recent periods seem active/stronger even though they might not be at all.

    So maybe it makes sense.

  112. Posted Sep 14, 2007 at 11:32 AM | Permalink

    Have you noticed? Media are labeling tropical storms like “hurricanes”. I’m astounded.

  113. RomanM
    Posted Sep 14, 2007 at 12:28 PM | Permalink

    #108 – mr mosher.

    Several of your names are a bit frightening. In particular, Bruce raises an image of Robert the bruce – a big Scotsman swinging an axe whom I wouldn’t want to meet in a dark alley or in a strong wind. I would suggest Barney instead – who could be afraid of a small purple dinosaur? As well, Gavin brings visions of rising temperatures and coastal flooding (and according to one website, originates from the Scottish meaning white hawk!!!)! No, I think Grover or Gumby would be preferable.

  114. Posted Sep 14, 2007 at 12:39 PM | Permalink

    Regarding Humberto, here’s an excerpt from the 11:00AM September 12 NHC discussion:

    TROPICAL CYCLONE ADVISORIES ARE BEING
    INITIATED. WITH 38 KT WINDS REPORTED FROM SHIP V7DI7…THE SYSTEM
    MIGHT ALREADY BE A TROPICAL STORM…BUT FOR THE MOMENT THOSE WINDS
    ARE JUDGED AS UNREPRESENTATIVE OF THE CYCLONE SCALE. THE INITIAL
    INTENSITY IS ESTIMATED TO BE 30 KT FOR NOW…

    As indicated, there was already evidence of Humberto being of tropical storm intensity even before it was classified as a depression.

    The problem was that neither the NHC nor the models (other than the often-nutty models) predicted tropical cyclone formation, so Humberto was a surprise to forecasters. Since there is a human bias towards seeing what we expect to see, and the NHC expected to see no formation, they tended to underestimate Humberto.

    Regarding rapid strengthening, the strong portion of Humberto was quite small, perhaps 50 miles across. Such small systems can change intensity, up and down, rather quickly. The famous Felix from earlier this season was also a small storm.

  115. steven mosher
    Posted Sep 14, 2007 at 12:52 PM | Permalink

    RE 113.

    Good suggestions all. My scary names come next. Roman is my choice for R and Zarathustra for Z.

    Boris of course will lobby for B, but I don’t think a Hurricane should Bore us. I prefer Brutus
    for the bad boy cat 5 hurricane.

    Or how about name changers.. it starts as a betty and ends as a brutus?

  116. Posted Sep 14, 2007 at 12:53 PM | Permalink

    Here are the 2007 to-date Atlantic ACE values. (ACE is a function of storm count, intensity and duration and so is a better single indication of seasonal activity than storm count alone.)

    Typical ACE for an entire season = 100

    2007 To-Date Individual Storm ACEs:

    Barry 0.8
    Chantal 0.6
    Dean 33.8
    Erin 0.4
    Felix 16.5
    Gabrielle 1.0
    Humberto 1.4
    Ingrid (so far) 0.4

    Total ACE for 2007 to-date: 55

    Last week I thought that 2007 might end up around 130. Now, though, with the unfavorable conditions over the next week or two during the peak of the season, I’m beginning to doubt that we’ll get that high. We’ll see.

  117. Judith Curry
    Posted Sep 14, 2007 at 1:20 PM | Permalink

    Two years ago i thought the main problem was with the historical data, in the 1970’s and 1980’s. At this point, the data in the west pacific is probably worse than it was in the 70’s and 80’s owing to the discontinuation of the recon aircraft. And now we are seeing the confusion that can be caused in the North Atlantic by too much information. The satellite data record should eventually sort this out in some sort of a consistent way (kossin’s work was a first step in this direction), but there will be jumps when new techologies are introduced (passive microwave, scatterometers).

    The NHC seems to like to break records, no matter how obscure they might be (the humberto record seemed a bit of a stretch). This could be a result of their mission to save lives, whereby keeping hurricanes in public eye helps raise awareness. More likely, hurricane junkies (probably all of the NHC forecasters would meet this criteria) get really excited by the storms, and this just reflects their exuberance. in the little forecasting team i have at GT, i have one person who is a bonafide hurricane junkie (he is also the best forecaster in the group). He tends towards over exuberance, the other less passionate forecasters act as a balance.

  118. Bob Koss
    Posted Sep 14, 2007 at 1:35 PM | Permalink

    David Smith,

    RE: 109

    I just don’t get any respect. It may be a few years from now, but next time I’m in town I’ll show you. :)

  119. steven mosher
    Posted Sep 14, 2007 at 1:37 PM | Permalink

    RE 117. I’m glad you said that.

  120. steven mosher
    Posted Sep 14, 2007 at 1:40 PM | Permalink

    RE 118. Thas a good one it starts as hurricane Priscilla and ends as Tornado Peter.

    Roxanne to Rod is also a nice name changer.

  121. SteveSadlov
    Posted Sep 14, 2007 at 1:45 PM | Permalink

    RE: #116 – A modest proposal. If it’s got an ACE l.t. 1.0, it will be neither counted nor named. If 1.0 or above, it gets counted and named. (Just a note, ACE of certain non named Pacific Storms of non tropical origin or non named tropical features which have become extra tropical exceeded 1.0 …. hmmmmm, got some revising to do?)

  122. SteveSadlov
    Posted Sep 14, 2007 at 1:47 PM | Permalink

    Some food for thought:

    http://en.wikipedia.org/wiki/Columbus_Day_Storm

    http://www.wrh.noaa.gov/pqr/gallery6.php

    January 22-29, 1983 – The California coast was battered by a storm which produced record high tides, thirty-two foot waves, and mudslides, causing millions of dollars damage. The storm then moved east and dumped four feet of snow on Lake Tahoe.

    March 5, 1987 – A storm in the western U.S. produced heavy rain and high winds in California. Up to six inches of rain soaked the San Francisco Bay area in 24 hours.

    March 12, 1967 – A tremendous four day storm raged across California. Winds of 90 mph closed mountain passes, heavy rains flooded the lowlands, and in sixty hours Squaw Valley CA was buried under 96 inches (eight feet) of snow.

    October 2, 1882 – An early season windstorm over Oregon and northern California blew down thousands of trees and caused great crop damage in the Sacramento Valley.

    December 21, 1964 – A great warm surge from the Pacific Ocean across Oregon and northern California brought torrential rains on a deep snow cover resulting in record floods.

    http://www.santacruzsentinel.com/extra/century/81/index.html

    [See items regarding Jan 1982 and Feb 1982 storms]

    http://www.jstage.jst.go.jp/article/jmsj/83/4/531/_pdf

    [Un-named]

  123. Posted Sep 14, 2007 at 2:00 PM | Permalink

    Re #118 But I would tremble at the approach of Hurricane Koss :)

  124. steven mosher
    Posted Sep 14, 2007 at 2:25 PM | Permalink

    re 123. What do you call a guy with no arms and no legs in your pool?

    Bob.

  125. steven mosher
    Posted Sep 14, 2007 at 2:31 PM | Permalink

    re 122

    March 12, 1967 – A tremendous four day storm raged across California. Winds of 90 mph closed mountain passes, heavy rains flooded the lowlands, and in sixty hours Squaw Valley CA was buried under 96 inches (eight feet) of snow.

    Ok. that’s not golfing weather

  126. steven mosher
    Posted Sep 14, 2007 at 2:58 PM | Permalink

    This was Not a good day for golf

    http://www4.ncdc.noaa.gov/cgi-win/wwcgi.dll?wwevent~ShowEvent~70073

    In the spring we had better weather.

    http://www4.ncdc.noaa.gov/cgi-win/wwcgi.dll?wwevent~ShowEvent~70101

    I dont remember this day

    http://www4.ncdc.noaa.gov/cgi-win/wwcgi.dll?wwevent~ShowEvent~69007

    before I was Born

    http://www4.ncdc.noaa.gov/cgi-win/wwcgi.dll?wwevent~ShowEvent~68728

    Hurricanes in the midwest!
    its the end of the world as we know it.
    Its not a Tropical storm. It’s not a Hurricane. It’s a WOLVERINE.

    I’ll name it Bo.

    http://www4.ncdc.noaa.gov/cgi-win/wwcgi.dll?wwevent~ShowEvent~360077

  127. SteveSadlov
    Posted Sep 14, 2007 at 3:01 PM | Permalink

    RE: #125 – The ole sand wedge don’t work too well in several feet of fresh powder, that’s for sure. Can even lose a ski in that much of it! :)

  128. Posted Sep 14, 2007 at 3:16 PM | Permalink

    Hurricane wind estimates are part objective and part subjective. This is illustrated by a glance at the Hurricane Katrina plot . The dark line is the official wind speed estimate while each symbol represents a measurement (aircraft, satellite, surface, dropsonde, etc). The analyst uses judgment to select which measurements to believe, which introduces subjectivity.

    In the case of Katrina the analysts choose a middle road. On the other hand, here’s a 2006 storm named Ernesto . The data shows lower-than-hurricane (65 knots) winds (except for satellite estimates) but the analysts chose to grant it 65 knot winds and thus make it a hurricane. At the time it was approaching land (Haiti), so the naming was probably to help alert people.

  129. Kenneth Fritsch
    Posted Sep 14, 2007 at 3:20 PM | Permalink

    I am suggesting that names start with the category level and then progress as (and if) the storm grows. For example, I submit the progression, Bobbie, Robbie, Bob, Rob, Robert and finally Rapacious Robert. Using my own name I would submit Kenny Boy, Kenny, Ken, Kenneth and Conquering Kenneth. A girl’s name progression might be Baby Beth, Beth, Betty, Elizabeth and Energetic Elizabeth. The storm for the records would be that recorded with the highest category it reached.

    A year with a lot of little storms would then be recalled not as year xxxx with all those storms but the year of Bobbie, Kenny, Ronny, Beth, Baby Sally etc, mixed with a few Adams, Fredricks, Berthas and Sarahs.

    I have 2 questions: Do tropical storms merge? And if they do and a storm in one basin with a girl name merged with one with a boy name in another basin would they take the girl name or the boy name or would they have a hyphenated name.

  130. Posted Sep 14, 2007 at 3:51 PM | Permalink

    Re #129 Ken I like your progressive system :)

    I also like the idea of using the hair of a Weather Channel meteorologist (the kind who lean sideways on a beach in a hurricane) to indicate windspeed. If they’re on the beach and the hair is barely ruffled then it’s a tropical storm. If the hair blows every which way it’s a category 2. The the hair looks sandblasted it’s a category 4.

    If the toupee blows away it’s a cat 5.

  131. SteveSadlov
    Posted Sep 14, 2007 at 4:11 PM | Permalink

    RE: #129 – RE: mergers – I can check and see what names are currently in vogue with the gender challenged …. after all, this is an upper 30s N latitude, Pacific Coast location … ;)

  132. John M
    Posted Sep 14, 2007 at 4:37 PM | Permalink

    re #129

    I have 2 questions: Do tropical storms merge? And if they do and a storm in one basin with a girl name merged with one with a boy name in another basin would they take the girl name or the boy name or would they have a hyphenated name.

    I don’t know the answer, but I’m willing to bet it will be called unprecedented and yet more evidence of AGW.

    re# 126

    Hurricanes in the midwest!
    its the end of the world as we know it.
    Its not a Tropical storm. It’s not a Hurricane. It’s a WOLVERINE.

    I’ll name it Bo.

    Based on current events, “puddy tat” might be more appropriate. (Speaking as a former Michigander and a pained fan.)

  133. Bill F
    Posted Sep 14, 2007 at 5:08 PM | Permalink

    #117 Judith,

    If you want some hilarity go read the comments late at night on Jeff Master’s blog posts at Weatherunderground when there is a storm intensifying in the Caribbean. The hurricane junkies there take irrational exuberance to a whole new level. The really weird part is seeing the people who are such junkies that they want the hurricane to come to their location so that they can ride it out. They will seize on any little wobble in course over a few hours time as evidence that a storm is shifting track and will start heading right at them. There were several who were absolutely convinced that Dean was going to turn right over Cuba and bust through the high pressure ridge and head for the Florida panhandle. It would be sad if it weren’t so funny to watch.

  134. K
    Posted Sep 14, 2007 at 5:34 PM | Permalink

    Do tropical storms merge?

    Having no knowledge or qualifications whatever I will guess that it would not happen unless there were other factors involved.

    As two storms, each rotating the same, approach each other I visualize that at the contact point the winds would be in opposing directions.

    What would follow is hard to imagine. But I think that each storm would seem to the other somewhat like a shore with very steep and high mountains. Hurricanes don’t do well hitting such a shore.

    I think we should try it and see.

  135. SteveSadlov
    Posted Sep 14, 2007 at 5:35 PM | Permalink

    RE: #128 – RE: Ernesto – I wonder what made the analyst decide to select 65Kt as the sweet spot for that line in that peak region? (As if I had to ask)

  136. STAFFAN LINDSTROEM
    Posted Sep 14, 2007 at 6:28 PM | Permalink

    #105 StevOK…Where to start???
    en Mosher…Of course you’re not the devil…Did I say/write so?? I’m the Devil
    after all how goes the saying? In Hell the Swedes are the humourists…Hallström’s film
    “Mitt liv som hund” …If you remember the scene where young Mr Glanzelius falls
    through the glass roof down to …don’t remember his name but I think he was modeled
    on Erik Höglund, a glass designer (my uncle was one too and knew him well I think.
    Both are dead…I may have “met” him once..Höglund..GWS…at an early age!) I also delivered Lena Olin’s
    mail once on Strindbergsgatan in 1988 or 1989 and heard her 6?-year son (with former
    husband Örjan Ramberg) yell: Mom! “Posten kom!!” [Surprise, surprise November?? afternoon]
    I also delivered Peter Stormare’s morning paper to his closet flat in Stockholm Old City at about
    the same time. Thinking of “Fargo”(have just seen some scenes) Steve Buscemi was reported
    yesterday on Swedish National Radio P1 Kulturnytt to have been very nervous doing
    some scenes with Clash’s Joe Strummer in Jarmusch’s “Mystery Train” Of course yours truly
    met Joe Strummer or his imposter in Mallia in Crete in July 1980 …Johnsen sounds more
    Norwegian/Danish, not Johnson????
    …#113 RomanM …as you know from Stones song “Sympathy for the Devil” he’s a man of class
    and taste and so am I mostly classical, jazz-listening but good rock especially in the summer
    is never wrong and “Bruce”… most people on this planet would think of a certain Mr Springsteen
    from NJ??? No?? …
    The “Perfect Storm” of Halloween 1991 one of the highest waves 12m was recorded at a buoy
    at 66.6 W…(!)..At the same time the Blizzard in the N midwest MN,WI etc…Guess my
    neighbour’s name? BLIZZARD…PS. I HAD NOT seen TS “Ingrid” when I wrote about”Inga
    Lindström”…Mosher…Dilbert and Gavin are of same class I suppose “Gabrielle-type”… people
    enjoying walking into the small big waves..not even TWC could make a scary story out of her…
    Percy Rosberg was Björn Borg’s early trainer…So I called him for advise how to be better than
    his former adept (I’m exactly one year older than Borg, born June 6 1955…) His wife answered
    and later Percy called back to my workplace John Wall hardware store screws and bolts…
    He asked if this was John Wall ? No I responded he’s been dead for 40 years!! (actually
    it was some 70 years or so…So all this bluddering…the “Unperfect Brainstorm” would not
    be in place if we had had a “real” hurricane season …The flashy storms this year is not much
    to write about apart from tragic “Dean” and “Felix” But Hattie/Simone/Inga of 1961 was much
    worse, it reshaped half of then British Honduras…Even a permanent city formed from hurricane
    refugee camp: “Hattieville”(Wikipedia)…Enuff for now…

  137. steven mosher
    Posted Sep 14, 2007 at 6:46 PM | Permalink

    re 136

    “#105 StevOK…Where to start???
    en Mosher…Of course you’re not the devil…Did I say/write so?? I’m the Devil
    after all how goes the saying? In Hell the Swedes are the humourists…Hallström’s film
    “Mitt liv som hund” …If you remember the scene where young Mr Glanzelius falls
    through the glass roof down to …don’t remember his name but I think he was modeled
    on Erik Höglund, a glass designer (my uncle was one too and knew him well I think.”

    That was a funny scene. My family won’t let me watch the film anymore so I have
    to sneak.. like the old man and his porno. I prefer the swedish
    version.. Not that I speak it, but the musicality of the language has to be experienced.

    ” Steve Buscemi was reported
    yesterday on Swedish National Radio P1 Kulturnytt to have been very nervous doing
    some scenes with Clash’s Joe Strummer in Jarmusch’s “Mystery Train” Of course yours truly
    met Joe Strummer or his imposter in Mallia in Crete in July 1980″

    Ha, A Clash Fan. London’s calling. Never met them, but I did see them at The LA
    Colusium. They Opened for the Who.. I think it was early eighties.

    “…Johnsen sounds more
    Norwegian/Danish, not Johnson????” yes Johnson. Irma Johnson.

  138. Posted Sep 15, 2007 at 8:11 AM | Permalink

    A plot worth a glance is this one . It plots, for all seasons since 1900, the ACE per storm (total ACE for a season divided by the number of storms in that season).

    ACE is a function of the number of storms, their duration and their intensity. In a sense ACE is the energy used or released by the storms.

    What the plot shows is that, if one takes the historical data at face value, then the individual storms have been trending towards weakness over the last 100+ years.

    This, I am pretty sure, is contrary to the expectations of both the AGWs (Emanuels) and classicists (Grays). AGW folks probably expect some rise over time, consistent with SST behavior, while the classical view expects flatness or a slight rise.

    So, what is the plot saying? Well, to me it says, “don’t take the historical data at face value” and is another indication of the effect of changes in detection and measurement methods.

    As detection methods have improved there have been more and more weak/marginal storms incorporated into the data, tending to lower the ACE/storm ratio. But, to convolute things, storm duration and wind measurement have improved over the decades, tending to increase ACE/storm. One cannot assume that somehow the two trends luckily cancel each other.

    The data from 1980 forward is probably about right, although we likely see improved detection (from things like shore-based Doppler radar and buoys, GPS windsondes and better on-board radar) increasing the number of very weak systems while also increasing the peak wind detection. But, there is also the AMO impact with a shift towards storms in the deep tropics.

    I may do a blog article which tries to qualitatively untangle the historical factors affecting ACE/storm but that would undoubtedly involve a lot of conjecture. It would also be good exercises to incorporate Landsea’s undercount guidelines and to do this for US landfall-only storms, if time allows.

  139. Kenneth Fritsch
    Posted Sep 15, 2007 at 10:37 AM | Permalink

    Re: #138

    I say go for it David. In scientific papers the subject matter normally involves only small parts of the total picture and this subject matter, and perhaps space, restrictions seem at times to allow the authors of scientific papers to put the blinders on and ignore some of these bigger picture factors. That is why I find that blog discussions of these matters can be more informative and far reaching than reading published papers.

    Blogs do not have the scientific rigor of a peer-reviewed paper, but I see the day coming when a lack of a blog discussion of a published article and/or its subject matter will be like doing without the creature comforts of air conditioning after we have become accustomed to it.

  140. _Jim
    Posted Sep 15, 2007 at 12:27 PM | Permalink

    David S., 138, writes:

    The data from 1980 forward is probably about right, although we likely see improved detection (from things like shore-based Doppler radar and buoys, GPS windsondes

    Do remember, though, the following:

    1) that Doppler RADAR (the network of WSR-88Ds around the county) didn’t start until fall 1990, and the last operational RADAR was installed in northern Indiana in late June 1997.

    In Miami, the new Doppler radar (WSR-88D) was installed ahead of schedule due to Andrew in April, 1993.

    Before then it was the manually-operated tube-type WSR-57 RADARs and a number of gap-filler WSR-74 C-band (5 cm) and S-band (10 cm) RADARs between those all S-band WSR-57 RADARs.

    Title: “History of Operational Use of Weather Radar by U.S. Weather Services. Part II: Development of Operational Doppler Weather Radars” –

    Link: http://ams.allenpress.com/perlserv/?request=get-document&doi=10.1175%2F1520-0434(1998)013%3C0244%3AHOOUOW%3E2.0.CO%3B2

    or Google these individual terms: WSR-88D history deployment

    and choose the 4th item returned from allenpress.

    2) The GPS ‘NAVSTAR’ system became declassified and available for civilian use in 1983, but the initial GPS receivers (“user segment” equipment) were large and bulky (the original ManPack GPS receiver TI developed circa 1978 for use was just that; a back-pack sized unit) and the HDUE (High Dynamic User Equipment for airborne platforms) unit was a full 19″ wide and two feet deep!

    In 1986 the accident of the space shuttle “Challenger” meant a drawback for the GPS program, as the space shuttles were supposed to transport Block II GPS satellites to their orbit!

    In 1990, during the (first) Gulf War civilian GPS receivers were pressed into service …

    I looked over the wikipedia site and it looks reasonably accurate:

    http://en.wikipedia.org/wiki/Global_Positioning_System

  141. Posted Sep 15, 2007 at 1:19 PM | Permalink

    Re #139 Ken I’ll put something together over the next several days. I’d particularly like to explore the impact of Landsea’s adjustment but need to figure out a basis for a typical ACE for missed storms.

    Re #140 John thanks for the info. The pace of technological improvement hasn’t slowed a bit.

    In 2005 Cindy was declared to have been a hurricane based on reanalysis of Doppler data. That classification would not have happened pre-Doppler.

  142. Judith Curry
    Posted Sep 15, 2007 at 2:48 PM | Permalink

    David, the effect of the landsea correction is pretty huge (note the landsea correction is relevant only for major hurricanes before 1970). After looking at the intensities before 1970 both with and without the landsea correction, I’ve come to the conclusion that neither version makes sense. Some sort of correction is needed, but landsea’s correction gives wind speeds that look very strange. Note that the landfall wind speeds since 1950 seem ok. This is what my analysis has shown anyways.

  143. Posted Sep 15, 2007 at 3:45 PM | Permalink

    This is a minor observation but sort of interesting:

    For 1933-1941, 69% of the peak storm wind measurements were attributed to ships. For 1942-1945, WW2 years, the ship-measured peak winds dropped to only 30%.

    My guess is that there were fewer ships and ship reports available during the war. Since typically a storm reaches its peak at sea, the reported WW2 intensities may be somewhat low since they depended on land measurements.

    (Why pick 1933-1945? The record after 1945 is affected by recon flight measurements. The record before 1933 doesn’t exist in a convenient form (Monthly Weather Review)).

  144. steven mosher
    Posted Sep 15, 2007 at 5:48 PM | Permalink

    During my more cynical periods I think This.

    Encourage them to name more and more storms. This morning I named two of my farts:
    Fanny and Zephyr.

    At some point they will discredit themselves with the people they are trying to help.
    The cry wolf syndrome.

    DEMAND they DUMP the “empirical” or “statistical” approach to Storm prediction.
    The NHC should only use physics based models to forecast the season.

  145. K
    Posted Sep 15, 2007 at 7:49 PM | Permalink

    #143: during WW2 their were far more ships at sea than previously. But in the North Atlantic almost all of them were in convoys. All in a convoy see one storm whereas random peacetime traffic would encounter more.

    And no one was using the radio unless necessary. I’m not sure how the ship were collected in peacetime but in wartime they would have been delayed by the absence of radio traffic.

    On the other hand. There were planes at all hours. And they collected weather reports as best they could – without radar it was mostly a guess. Most planes were doing their best to not find storms.

    By 1943 planes with radar were over all areas to suppress the Uboats and these planes would have found them.

    I think the naming debate is much like the temperature arguments. Eventually facts will settle the matter and those who exaggerate will find themselves painted into a corner.

  146. Posted Sep 15, 2007 at 8:50 PM | Permalink

    Re 143:

    Have you considered that the peak wind speeds may have dropped, ie, it’s not an observation error, but an observation?

    Of course, you then have to find a plausible mechanism which reduces the efficiency of the great heat engine at the heart of the hurricane.

    JF

  147. _Jim
    Posted Sep 15, 2007 at 10:44 PM | Permalink

    K at #145 September 15th, 2007 at 7:49 pm wrote:

    By 1943 planes with radar were over all areas to suppress the Uboats and these planes would have found them [storms, presumably].

    But, we must consider the specialized nature of those RADARs; these were not weather RADARs per se as found on aircraft today, nor were these the more normal ‘search’ RADARs that a lot of those in meteorology are familiar with today.

    Specialized RADARS of the type in early ASW often employed fixed antennas (esp at the lower VHF/UHF bands) aligned in fixed positions on the fuselage; centimetric (S thru X band or microwave band) RADARs coming into use later in the war had more versatility, but the displays still weren’t of the Plan-Position-Indicator style or even ‘angular sector’ scanned affair using ‘gimbaled’ antennas behind radomes in the aircraft’s nose; the purpose of these early RADARs was specific: locate (if not simply detect) subs/U-boats, at night, or in reduced optical-visibility weather. Sonobuoys also made their appearance and were effective in combatting U-boats. Sorry to belabor these points; it is both hobby and a serious pursuit with me.

  148. Posted Sep 16, 2007 at 11:18 AM | Permalink

    Re #142 Thanks, I’ll read the Landsea papers to understand what he did and why. The specific adjustment I plan to check is the one which was referenced in Mann’s EOS article, which refers to Landsea (2007).

  149. K
    Posted Sep 16, 2007 at 1:24 PM | Permalink

    Jim: First I thank you for not remarking much upon my garbled comment. I rushed to meet the grandkids and just typed. When I returned and reread my message I wondered what I had been thinking. There were several unclear passages.

    I agree with you about the radars function. My intended point was that it took a while before the campaign against the Uboats employed enough planes to cover the N. Atlantic in some detail at all hours. The radar itself was of limited or no value in detecting a storm but the planes couldn’t miss simply because they were present.

    Actually measuring wind was another matter. Patrol planes could sometimes make a good estimate from drift meters in daylight. And average winds over a longer period could be calculated from location fixes, but that wasn’t much use in estimating peak wind.

    Planes simply crossing the Atlantic didn’t want to deal with storms and weren’t going to notice much that escaped patrol planes. And I assume ships made no radio traffic except in distress or for military needs. That is why I think ship reports were probably collated after the fact or perhaps that was never systematically done.

  150. D. Patterson
    Posted Sep 16, 2007 at 3:57 PM | Permalink

    Re: #145, #149

    The ASW campaign was not as all encompassing in the areas being searched at any one time as may be first imagined. The interception and breaking of the ULTA code traffic made it practical for the Anglo-American ASW forces to focus and concentrate their searches on those Kriegsmarine grid areas where the U-Boats were already known to be present. Consequently, vast areas of the Atlantic Ocean were unobserved where the U-Boats and Allied convoys were not present at a given time.

  151. SteveSadlov
    Posted Sep 17, 2007 at 10:54 AM | Permalink

    At present, there is essentially nothing of interest going on in the tropics. After a slight nudge north, late August into about a week ago, the ITCZ has resumed its annual antipodal shift. The Polar Jet is pumping cold fronts into the Gulf Of Mexico and Western Atlantic. More transient disturbances to the Jet appear to be all but certain, this week. We are now at 9 named storms including all the bogus named ones. Depending on who you talk to, that would make somewhere between 6 and 8, inclusive, named storms. I bet back in the spring we’d have 9 named storms this season.

  152. SteveSadlov
    Posted Sep 19, 2007 at 11:24 AM | Permalink

    First a request – can this be moved to the Hurricanes category? It will become very difficult to find over time.

    Now a comment. The count padders are champing at the bit to name this one:

  153. SteveSadlov
    Posted Sep 20, 2007 at 4:17 PM | Permalink

    RE: #152 – Like I wrote ….

    A RECONNAISSANCE AIRCRAFT INVESTIGATING THE AREA OF LOW PRESSURE IN
    THE EASTERN GULF OF MEXICO FOUND A BROAD CIRCULATION CENTERED ABOUT
    115 MILES WEST-SOUTHWEST OF ST. PETERSBURG FLORIDA. THE AIRCRAFT
    WILL CONTINUE TO INVESTIGATE THE LOW THIS AFTERNOON…BUT THERE ARE
    NO INDICATIONS YET THAT THE LOW HAS BEGUN TO ACQUIRE TROPICAL
    CHARACTERISTICS. THUNDERSTORM ACTIVITY WITH THIS SYSTEM REMAINS
    LIMITED AND DISORGANIZED. HOWEVER…THIS SYSTEM HAS THE POTENTIAL
    TO BECOME A SUBTROPICAL OR TROPICAL CYCLONE OVER THE NEXT DAY OR SO
    AS IT MOVES WEST-NORTHWESTWARD OVER THE WARM WATERS OF THE GULF OF
    MEXICO. ALL INTERESTS ALONG THE NORTHERN GULF COAST SHOULD MONITOR
    THE PROGRESS OF THIS SYSTEM.

    Scraping the bottom of the barrel once again in search of something to count. “If we name it, they will count….” BAH! (HUMBUG!)

  154. John M
    Posted Sep 20, 2007 at 4:42 PM | Permalink

    So can any of you ACE calculators tell me if Ingrid qualifies as the “Weakest Tropical Storm EV-V-Ve-r-r-r”? Just curious, in this year of record breakers.

    Undoubtedly, we’ll soon see a paper in Nature telling us that the reason Ingrid didn’t live up to expectations (model “consensus“) was due to some teleconnection, whereby some previously unknown, but now scientifically settled, CO2-induced atmospheric vibrational mechanism transferred most of her energy to Humberto (and now to “93L”, the one they’re dying to name). This is undoubtedly a trend that will lead to an ever-increasing catastrophic sequence of near-shore hurricanes forming quickly and unpredictably at the expense of hurricanes that pre-AGW would have dissipated energy safely at sea.

    I hear Michael Mann can prove it statistically, even though he’s not a statistician.

  155. Kenneth Fritsch
    Posted Sep 20, 2007 at 6:23 PM | Permalink

    Steve Sadlov, can you say, Jerry. We are prepared to name and claim number 10 for the NATL season. Jerry was being conspicuously down played even on the Weather Channel. Looking at my historical storm occurrences by month indicates that when we have this many storms in a season that the final months can be very active. Anyway, I think us high counters are very much still in the game.

  156. Posted Sep 20, 2007 at 7:11 PM | Permalink

    Actually Ingrid is not even close to being the weakest storm ever, thanks in part to her brothers and sisters of 2007. Here are the 2007 ACE values, by storm:

    Dean – 33.8
    Felix – 16.5
    Humberto – 1.4
    Gabrielle – 0.97
    Ingrid – 0.82
    Barry – 0.77
    Chantal – 0.61
    Erin 0.37

    (A typical Atlantic storm has an ACE of 10, more or less).

    I’m beginning to worry that global warming is causing Atlantic storms to weaken, with potentially catastrophic social consequences. Storm junkies will become idle, with little to watch on the Weather Channel or internet during the long hot summers, will they then release their excess energy by torching cars and robbing liquor stores?

    The prospects are horrid.

  157. Kenneth Fritsch
    Posted Sep 20, 2007 at 7:50 PM | Permalink

    Re: #156

    I’m beginning to worry that global warming is causing Atlantic storms to weaken, with potentially catastrophic social consequences. Storm junkies will become idle, with little to watch on the Weather Channel or internet during the long hot summers, will they then release their excess energy by torching cars and robbing liquor stores?

    The prospects are horrid.

    David, I have a difficult time visualizing Weather Channel watchers (and. yes, you know who we are) torching cars and robbing liquor stores, but, though you may have exaggerated in this instance, your intentions are good, i.e. reminding that GW is always bad.

    The Weather Channel guy did say that Jerry could bring much needed rain to the areas it might hit and commented that the consequences of tropical storms are not always bad. I am thinking then that perhaps our good intentions need to consider Jerry not to be a spawn of GW.

    I was reminded of changing evaluations by a judge in a pie baking contest that I saw the other night on the Food Channel who kept saying this is the best pie he had tasted all day and was bound to win first prize. He said it at least 4 times. Could it be that with the advent of GW we will keep adjusting our evaluations to something like “now is the best climate ever so lets keep it that way”.

  158. Posted Sep 20, 2007 at 8:19 PM | Permalink

    Ken this evening there are two vortices in the Gulf of Mexico circling around the upper low. We also have a seedling in the Caribbean which shows some signs of coming to life. With a little luck we might get three named storms over the next 72 hours and be well on our way to 15+ for the season :)

    Maybe even four if we count the upper low.

  159. SteveSadlov
    Posted Sep 20, 2007 at 9:12 PM | Permalink

    I already saw elsewhere, in effect “we have tied the 2006 season” yada, yada. Much hay will be made of it if we surpass it (according to the National Hysteri … oops, Hurricane Center count.

  160. Posted Sep 21, 2007 at 9:26 AM | Permalink

    Well, the spinning thunderstorms in the Gulf of Mexico have been labeled as a subtropical depression. “Subtropical” means that it does not have a warm center. Maybe we’ll get a named system later today.

    Subtropical depressions are usually high-latitude and cool weather events. This is the first September subtropical system in the Gulf of Mexico on record.

  161. Kenneth Fritsch
    Posted Sep 21, 2007 at 10:41 AM | Permalink

    Re: #158

    With a little luck we might get three named storms over the next 72 hours and be well on our way to 15+ for the season.

    That’s the ticket: leave no subtropical depression unturned and be quick to claim and name. This season is turning out to be just as I forecast.

  162. SteveSadlov
    Posted Sep 21, 2007 at 11:05 AM | Permalink

    RE: #160 – My little “dry run” over on my “NHC” joke blog using a typical disk of high altitude cold air sliding down into the Great Basin was actually not far off the mark. The East-of-the-Rockies versions of these systems are the only thing going on in terms of “tropical” activity. There have been almost no truely warm core from the get go types of systems this year other than Dean and Felix (and maybe Barry, depending on how you view it).

  163. steven mosher
    Posted Sep 21, 2007 at 11:53 AM | Permalink

    They named a Storm Jerry? Last name Lewis? what a joke.

    Dean Martin would be mad. Oh wait we had Dean. Lots of hot air.
    Now we got Jerry. The buddy love of storms. A Mouse of sorts.

    No Toms this year, not even a Cat 1 Tom.

  164. Earle Williams
    Posted Sep 21, 2007 at 11:57 AM | Permalink

    Re #163

    steven mosher,

    Where should I send you the invoice for my keyboard replacement?
    ;-)

  165. Posted Sep 21, 2007 at 12:09 PM | Permalink

    I’m starting to worry.

    I took a look at trends in weak Atlantic storms and in total storms. The results are here .

    If the current naming trends continue then we’ll run out of hurricanes in early 2019.

  166. Damek
    Posted Sep 21, 2007 at 12:51 PM | Permalink

    RE: #160

    It looks like NOAA went back and have now classified depression 10 as TROPICAL instead of subtropical.

  167. SteveSadlov
    Posted Sep 21, 2007 at 12:54 PM | Permalink

    RE: #166 – What a farce.

  168. steven mosher
    Posted Sep 21, 2007 at 1:39 PM | Permalink

    RE 164.

    Ha.. Did I give you a nose enema?

    The NHC is making my local weatherwench look like a wizard.

    YOU BETTER FRICKIN LAUGH SADLOV.

  169. SteveSadlov
    Posted Sep 21, 2007 at 1:39 PM | Permalink

    The die is cast, it will be named, right when it reaches the first “S” on the track:

    http://www.nhc.noaa.gov/refresh/graphics_at5+shtml/145538.shtml?3day#contents

    That will be true if sustained winds are anywhere between 15 and 50 Kt.

    “For the love of Big Brother”

  170. steven mosher
    Posted Sep 21, 2007 at 1:41 PM | Permalink

    Dean, felix and barry.

    It’s a new show on WE.

  171. SteveSadlov
    Posted Sep 21, 2007 at 1:48 PM | Permalink

    RE: #168 – Hey bro’ if it’s dark or otherwise ironic humor, I’m all over it ;)

    I can’t wait to get my “NHC” blog going for real. I’ll invite a few folks to do guest posts ……

    “ANNOUCEMENT: THE SAN FRANCISCO BRANCH OF THE NATIONAL HYSTERIA CENTER IS NOW OPEN. OUR FORECASTS AND WARNING SYSTEM COVER THE NORTHERN HEMISPHERE PACIFIC. OUR MOTTO IS, ‘COUNT UNTIL YOU DROP.’ BASED ON OUR RECENT BENCHMARKING EXERCISE WITH HQ IN MIAMI, WE HAVE CONCLUDED THAT THE OFFICIAL PACIFIC TROPICAL CYCLONE SEASON WILL BE 365.25 DAYS AND WILL RUN EVERY YEAR FROM 0000Z 01-JAN 01 THROUGH 2359Z 31-DEC. WE WILL POST OUR OPERATIONAL DEFINITIIONS AT OUR SITE IN NOVEMBER.

    BLATHER.”

  172. steven mosher
    Posted Sep 21, 2007 at 1:56 PM | Permalink

    re 171.

    Light humour is not funny.ask einstein.

    You also need to start the “circuit earth” site for EEs

    Iron Knee is my indian name.

  173. tetris
    Posted Sep 21, 2007 at 2:11 PM | Permalink

    Re: 171
    I’ll be more than happy to serve as your Canadian Pacific NW Gulf Islands observatory. :)

  174. tetris
    Posted Sep 21, 2007 at 2:17 PM | Permalink

    Re: 171
    Also, I speak 4 languages which should be of some help in reducing the risk of us running out of names…:)

  175. David Smith
    Posted Sep 21, 2007 at 2:37 PM | Permalink

    Steve S., here’s another non-tropical candidate being watched closely by the NHC, from the current outlook summary:

    NEARLY STATIONARY NON-TROPICAL LOW LOCATED OVER THE CENTRAL
    ATLANTIC ABOUT 1100 MILES EAST OF BERMUDA HAS CHANGED LITTLE SINCE
    YESTERDAY…BUT IS STILL BEING MONITORED FOR SIGNS OF TROPICAL
    DEVELOPMENT.

    We may be on a roll :)

  176. tetris
    Posted Sep 21, 2007 at 3:26 PM | Permalink

    Re: 175
    Any further East and this “Non-Tropical” would be in my parents’ backyard in Bretagne. When do you figure the NHC might start naming good, ol’fashioned North Easters in their count?

  177. SteveSadlov
    Posted Sep 21, 2007 at 3:35 PM | Permalink

    RE: #176 – They already crossed that rubicon. Andrea and Chantal.

  178. SteveSadlov
    Posted Sep 21, 2007 at 3:46 PM | Permalink

    http://www.nhc.noaa.gov/refresh/graphics_at5+shtml/203028.shtml?tswind120#contents

    Perfect set up to be able to declare “It reached tropical storm intensity 1 mile before landfall”

  179. STAFFAN LINDSTROEM
    Posted Sep 21, 2007 at 4:01 PM | Permalink

    #169 Steve S TD10 Landfall in W FL as a TD then strenghtening
    inland to a TS, JERRY LEWIS that must also be a new unprecedented treat of
    tropical systems…YGMN HELL IS HERE…YOU’RE DONE SUCKERS…
    Is that heavy humour…or just stupid …BTW Steve Mosher Jerry is not
    Lewis but Seinfeld and I’m Devil Seinfeld his father…or dog..(if you’re
    familiar with Lee Falk’s “the Phantom”)…And Steve S, in your post-analysis
    of “Humberto” (did you watch TWC BTW??…Typical wind and rain-machine?? looked
    and smelled FAKE all the way to Sweden…) are you up to something?

  180. tetris
    Posted Sep 21, 2007 at 4:12 PM | Permalink

    Re:179
    Rena rama lurendrejeri

  181. STAFFAN LINDSTROEM
    Posted Sep 21, 2007 at 4:33 PM | Permalink

    # 178 Steve S actually 666 meters AFTER landfall according
    to my upscaled radar from Tallahassee…New Swedish
    Hurricane Center secret technology…BION…Seriously
    claiming to be able to pin down the center of that system is beyond anything CMIIW…

  182. SteveSadlov
    Posted Sep 21, 2007 at 4:39 PM | Permalink

    Thanks for the Friday laughs Steffan! :)

  183. STAFFAN LINDSTROEM
    Posted Sep 21, 2007 at 4:57 PM | Permalink

    #179 “Skit oxo jag kan inte ….” Tetris
    with knowledge? of the word “lurendrejeri”
    I guess one the four languages of yours is the language
    of the Devil, Swedish…LOL..Yesterday I self-snipped a rather
    lenghty rantish fantasia-brainhurricane on totally
    reflective material being made by,…, YGI, NASA.
    The bottom line was that UHI and local albedo changes
    caused by winter tourism is making tree-lines step up
    and glaciers melt faster…(Some glaciers are so small
    they can be “Christoed” …)BC W coast Sep winter…Checking EC they only have
    the 5-day forecast. What’s your source? Weather On Line
    has free 8-days FC now …Not very good NTS

  184. STAFFAN LINDSTROEM
    Posted Sep 21, 2007 at 5:07 PM | Permalink

    #181 End “that system” refers to 2007 TD10 not 2007 “Humberto”
    of course…

  185. steven mosher
    Posted Sep 21, 2007 at 5:09 PM | Permalink

    RE 179.

    Seinfeld? A storm about nothing? Is the Aurora Borealis toasting your head.

    Thanks for the laugh steffan. maybe someday we will trade your two FFs for a
    proper V.

  186. Philip Mulholland
    Posted Sep 21, 2007 at 5:55 PM | Permalink

    Re 180

    Hi Tetris
    Guess we’re going really international now…

    http://www.translation-guide.com/free_online_translators.php?from=Swedish&to=English

  187. SteveSadlov
    Posted Sep 21, 2007 at 6:47 PM | Permalink

    …TROPICAL DEPRESSION COMING ONSHORE…DID NOT STRENGTHEN…

    AT 700 PM CDT…0000 UTC…THE TROPICAL STORM WARNING FOR THE GULF
    COAST HAS BEEN DISCONTINUED.

    Say it with me now: Awwwwwwwwwwwwwww!

    …. the could padders could not be so bold as to stetch credulity with this one …..

  188. STAFFAN LINDSTROEM
    Posted Sep 21, 2007 at 7:36 PM | Permalink

    #187 Steve S That I call the LINDSTRÖM effect 87 minutes
    before 1900 CDT do I count right? NHC has a fear of “666”
    They hereafter dance after our pipes just like the rats
    of Hameln…LOL…BTW Another thread Steve S I checked München
    Riem and they had 17C as lowest night temp! I suspect you were in the hot eye
    of said city….written I mean…RIEM=FLUGHAFEN

  189. STAFFAN LINDSTROEM
    Posted Sep 21, 2007 at 8:27 PM | Permalink

    #188 Wait…Steve S Your “Atlantic Hurricane Season Prediction 2007″
    was 9, am I right..? So it could also be the “Sadlov effect”
    But we don’t count Andrea and Chantal? Half of Andrea (the Doria
    part ran into “Stockholm”, the ship, in July 1956 while yours
    truly was smuggeling silver plates over Öresund, well some
    weeks later perhaps (I was 14 months old and that I don’t
    remember that but other things, looking at danish TV for example)
    (I was sitting on a silver plate in the pram hence
    the prem-pram, I’m born 9 weeks too early…) Chantal is
    french and I met her in Crete in 1980 AFTER the München
    visit…
    But translation jokes:
    Swedish Volvo member magazine is called “Ratten”(swedish
    for”the steering-wheel” but german for “rats”
    Swedish BMW MC member magazine is called “Bumsen”
    and I suspect they know the german colloquial meaning
    of that verb…??? Check it out…Imagine if Richard M
    Nixon had said “I’m not a lurendrejare”…ENUFF!

  190. tetris
    Posted Sep 21, 2007 at 10:14 PM | Permalink

    Re: 183
    Staffan
    Bode i Sverige mellan 1974 och 1983. Disputerade i Lund. Var bor du nu?
    Re:185
    No Steven. No Seinfeld, no Aurora Borealis. Possibly Bob Dylan’s line about having that “electric storm howling between your ears”, or better yet, it “doesn’t take the weatherman to know which way the wind blows”. My comment to Staffan was in Swedish, freely translated as: “we’re being badly had” or in NA vernacular “more snake oil?”.
    Re: 186
    Philip
    It tends to get lost in the shuffle, even in immigrant-based societies such as Canada and the US, but there are many often quite rich languages in the world other than English. Ref: my comment in #176 for a pointer.

  191. Philip Mulholland
    Posted Sep 22, 2007 at 7:37 AM | Permalink

    Hi Tetris
    I suppose the you are thinking of Dublin born George Bernard Shaw’s comment “England and America are two countries divided by a common language.”
    My scottish wife would certainly agree with you about linguistic heritage.
    Mony a mickle maks a muckle.

  192. Philip Mulholland
    Posted Sep 22, 2007 at 7:58 AM | Permalink

    Cenedl heb iaith, cenedl heb galon.

  193. Posted Sep 22, 2007 at 11:30 AM | Permalink

    A quick look at the 2007 season’s storm count is here .

    The red line plots named tropical systems while the blue line plots those which reached hurricane intensity.

    So far, thanks to the counting of those quite weak tropical storms, we’re having a normal season (based on 1944-2002 climatology).

    (The major storm count (not plotted) is two to-date, also consistent with climatology.)

  194. tetris
    Posted Sep 22, 2007 at 12:35 PM | Permalink

    Re: 193
    David
    Thx. And if one were to take to quasi/borderline systems [including the NEasters we talked about yesterday] out of the tally, what would the result be? Instinctively it seems to me we would wind up with a below the line season. Also, you’ve pointed out that indivudual and commulative ACE values to date are below the norm. How would this plot?

  195. Posted Sep 22, 2007 at 2:11 PM | Permalink

    Re #194 Tetris, the historical averages suggest that three named systems are yet to form, with two becoming minor hurricanes. As a guess, I’d assign an ACE of 5 to the tropical storm and 15 to each of the minor hurricanes, giving us a projection of 90 for the entire season. Since the average ACE for a season is 100, we’d be near to slightly below normal.

    However, in looking at how wind shear is increasing (which inhibits ACE) and how much of the Atlantic continues to have anomalously stable air (which also inhibits ACE), I think that ACE projection of 90 may prove to be high.

    On storm count, five of the eight storms in 2007 have ACE values below 1.0 and several of those had arguable tropical characteristics. If three to five storms are excluded from the storm count then 2007 is clearly below-normal.

    On a side note, I suspect that Hurricane Humberto may have the lowest ACE (1.4) on record for a hurricane.

  196. K
    Posted Sep 22, 2007 at 3:03 PM | Permalink

    There is nothing in the Atlantic that is being tracked just now.

    That makes it likely – but doesn’t ensure – there will be no more names in September. And the named storms count would be right on the average curve. It would also put the total hurricane count well below the curve.

    Large hurricanes are so rare low that eyeball speculation is a total guess. We know when a season is high to date, but when it is low that tells us very little until the end. But the major hurricane curve flattens quickly in October.

  197. Posted Sep 22, 2007 at 4:15 PM | Permalink

    A similar plot, this time for the Eastern/Central Pacific, is here .

    The red line represents the named tropical systems while the blue line shows the ones which reached hurricane strength.

    The East/Central Pacific has been weak with regards to storm strength.

  198. Posted Sep 22, 2007 at 10:21 PM | Permalink

    One of the remarkable achievements of climatology has been the creation of sea surface temperature (SST) plots for remote regions of the oceans stretching back into the 19’th Century. When I see time series, like the SST of the tropical Atlantic between Africa and the Lesser Antilles for the 1920s, I wonder, “How dey do dat?”.

    The core of my question has to do with the number of observations. There are other, perhaps bigger, questions with regard to the accuracy of the measurement and the appropriateness of adjustments, but for now I simply wonder about the number of observations in remore regions of the tropical Atlantic.

    Finding data on actual observations has been difficult and if anyone knows of a place which discusses specifics on SST observation densities, please post.

    Anyway, I did find one map showing SST observations in the Lesser Antilles in July, 1930 ( link ). The numbers in the grid boxes are the number of SST observations in that box during the month. These are for island regions – the numbers of observations for the open-ocean region between the Antilles and Africa are undoubedly lower.

    I was stunned to see such large regions in traveled areas have so few observations. Combine that with the measurement difficulties and I’m left with the impression that SST reconstructions in the Antilles, and especially in the seldom-traveled regions to their east, are basically best guesses based on few actual observations.

    (Side note: The scarcity of ship observations may also indicate one reason why tropical storms, especially weak ones, were underreported in the past.)

  199. Posted Sep 22, 2007 at 10:34 PM | Permalink

    Landsea’s recent paper on cyclone count is here

  200. Philip Mulholland
    Posted Sep 23, 2007 at 5:51 AM | Permalink

    Ref 199

    Ref Fig 2 (a) in Chris Landsea’s paper.
    I wonder if the historic marine storm undercounting is better observed using an annual cumulative count graph?

  201. Posted Sep 23, 2007 at 11:03 AM | Permalink

    The recent Mann/Emanuel etc paper ( link ) includes a plot of sea surface temperature (SST) in the low-latitude tropical Atlantic. The plot, in Excel form, is here .

    I’m intrigued by the question of how historical SST are determined in the eastern Atlantic regions and I’m on a quest to learn about that. This effort is just starting but I did come across two maps I’d like to share. These are from Sadler et al 1987.

    The first is here . This is a plot for 1900-1979 (80 years) and shows the density of observations for 2×2 boxes averaged over that period. Note the sparse observations inside the red box, with the exception of a ship lane leading from South America to Europe.

    The second is here . This is a plot of the number of Atlantic obervations (entire ocean) by year. An eyeball estimate using this broad indicator is that sampling frequency pre-1950 was perhaps half the rate of the total 80-year period. As is obvious, too, there are big gaps in WW2 and WW1.

    Combining the two maps in a general way suggests that the MDR SST pre-1950 may have had two or three observations per 2×2 grid per month. Frankly I’m not sure it is that high, based on maps I’ve seen in several Monthly Weather Review archived issues. Combine this sparse sampling with the likely variation in sampling practices and SST and I have to wonder just how one detects a 1F change over 20 years.

    Among other things, this all makes me wonder about the SST plot which shows a 1940s peak that is below the current peak. Just how many observations were used to determine that peak, especially with the reduced WW2 observations?

    Anyway, the effort is just starting.

    (For anyone interested the Sadler map for all ocean basins is here . I wonder if Waldo hides in those white and pocked areas.)

  202. Posted Sep 23, 2007 at 8:58 PM | Permalink

    Subtropical storm Jerry was reclassified tonight. It is now a tropical storm, giving us 9 for the season so far.

    Jerry has minimal winds (35 knots) and is expected to be gone within a day. If so, it will be the fourth storm of 2007 to have lasted 24 hours or less.

    Also, there are three other seedlings which could conceivably reach cyclone status in the next couple of days. We’ll see.

  203. Posted Sep 23, 2007 at 9:01 PM | Permalink

    The Northern Hemisphere ACE is about 25% below normal to date. Link to update page. The East Pacific is well over 50% behind the 1970-2006 climatology through September 23. It is not often that the EPAC and NATL are BOTH below normal. Approximately 65% of the NH yearly ACE tally on average should have occurred through September 23. These calculations for the NATL do not include post-extratropical transition observations. If this is not done, for 2006, post ET NHC best track observations add roughtly 20% to the tally. However, the JTWC does not distinguish ET times until 2004, unlike the JMA best track. Thus, there are about 1,000 JTWC observations that need to be closely examined (from 1951-2003) to determine whether they are in fact past extratropical transition.

  204. Posted Sep 24, 2007 at 4:45 AM | Permalink

    Re #203 Nice link, Ryan, thanks for providing it!

  205. SteveSadlov
    Posted Sep 24, 2007 at 9:39 AM | Permalink

    RE: #202 – This one beggars belief. They declared the storm weakening and dying as it came ashore Friday. They took down the worrywartish overhyped TS warning. And then, later, they reclassified it, based on what the system morphed into after coming on land. Count padding at its most blatent. NHC – je accuse!

  206. David Smith
    Posted Sep 24, 2007 at 9:45 AM | Permalink

    Actually “Jerry” was a mid-Atlantic system that lasted all of 12 hours. Looks like a total ACE of 0.25, which is almost the lowest possible.

  207. steven mosher
    Posted Sep 24, 2007 at 9:49 AM | Permalink

    RE 205. Hurricane Dean martin needed a buddy storm.

  208. Kenneth Fritsch
    Posted Sep 24, 2007 at 9:49 AM | Permalink

    David Smith thanks for link to the Landsea paper on tropical storm series problems with changing detection capabilities over time. Without seeming overly presumptuous it appears very much in line with the approaches that have been taken at CA and with the same conclusions. Being a scientific paper it references claims by others without the more subjective comments that we sometimes make here, but he does note the references made by Mann and Webster and Holland to the history of passing ships not warned of storms detect them and than appears to reject this claim out of hand without eluding to the fact that, in my mind anyway, this is a very weak argument without a detailed accounting for it.

  209. SteveSadlov
    Posted Sep 24, 2007 at 10:02 AM | Permalink

    RE: #206 – Yeah, I realized that after looking around the web at some coverage. So, “Jerry” (the new one) was a nor’easter, just like Chantal, off of New England. Yah, that’s “tropical” (NOT!). Which makes this even more of a joke. The NHC really is the National Hysteria Center (and, the “count ‘em up” center for those still trying to make the case of “AGW means an increasing trend of TC count!”)

  210. Ryan Maue
    Posted Sep 24, 2007 at 10:33 AM | Permalink

    I wouldn’t belittle the NHC as the National Hysteria Center, since the forecasters writing the advisories did not sound too enthused about the development of Jerry in their discussions. The storm did have tropical characteristics, albeit very marginal. I would give the moniker to Accuweather.com, if any group, as hysterical.

    The question that arises: as Bill Gray, NOAA, Risk Prediction Inc., and the Farmers Almanac *publish* their seasonal forecast verifications, are they going to take credit or count the marginal storms in their year-end tally? I believe it would an extreme act of vanity and hubris for a Seasonal forecasting group to claim that they envisioned Andrea, Chantal, Erin, Ingrid, or Jerry back in April. Yet, Jerry and Chantal will count the same as Felix and Dean in the year-end counts. Of course, with PDI or ACE, it is not worth the effort to even archive the observations.

  211. steven mosher
    Posted Sep 24, 2007 at 10:37 AM | Permalink

    208.

    Kenneth do they have ship based storm counts both in and out of the satillite era?

    I’d expect that to a be overcount/undercount estiamtion tool

  212. STAFFAN LINDSTROEM
    Posted Sep 24, 2007 at 10:42 AM | Permalink

    #205 Steve S: Say after me: “J’accuse”(!) I’m the CA språkvårdare
    /besserwisser, you don’t need a capital B in english do you?!
    I think besides smorgasbord and ombudsman, sprakvardare could
    be one of the Swedish language’s big contributions to English…
    Jerry looks as much of a very week polar low displaced far
    south, where did they find the warmth in the NE quadrant…???
    I hereby baptize this 2007 Atlantic hurricane season: “The Joke Season”
    So after naming the storms we start naming the seasons…(Instead?!!!)

  213. SteveSadlov
    Posted Sep 24, 2007 at 11:58 AM | Permalink

    Sprakvardare … I like the ring of that!

  214. Kenneth Fritsch
    Posted Sep 24, 2007 at 12:34 PM | Permalink

    Re: #211

    Kenneth do they have ship based storm counts both in and out of the satillite era?

    I’d expect that to a be overcount/undercount estiamtion tool

    David Smith looked at that issue and should have a post in this thread with the findings. I’ll let him answer that one for you as I generally only use this information and not find and use it as David does so frequently.

  215. David Smith
    Posted Sep 24, 2007 at 12:34 PM | Permalink

    Ryan, your website is nice. Could you make available the historical ACE values for the basins by date? For instance, the historical to-date ACE for the Atlantic for September 24? Thanks.

  216. tetris
    Posted Sep 24, 2007 at 12:36 PM | Permalink

    Re 210
    Ryan
    There is a crucial difference between Accuweather and the NHC, in that the latter is a US federal government organization, which interestingly enough resorts under the Department of Commmerce. The latter ought to remind the good folks at the NHC of their core mandate, which is to provide reliable forecasts and credible warnings about storms that may have a signifianct economic impact.

    By including assorted nor’easters and other things the dog brought home in their storm/hurricane count, the NHC are not only singularly compromising their credibility, but additonally are playing into the alarmists’ hand. As discussed above [with David Smith], take the 3 or [now] 4 marginal storms out of the currrent count and you wind up with a 2007 record that is very much below the line, and the NH ACE value of -25% you mention would be even lower.
    Jerry? A TS? With an ACE value of 0.25? Indeed.
    Credibility once lost, is extremely hard to re-establish.

  217. SteveSadlov
    Posted Sep 24, 2007 at 1:33 PM | Permalink

    RE: #216 – If Jerry was a tropical cyclone and in fact rose, albeit marginally, above the wind break point (and was hence, a countable and nameable tropical storm) then so too was the unnamed storm which hit California Friday through Sunday. Plus, the one which hit us did lots of damage. Mudslides in LA, ruined raisin crop, etc. (Of course, Jerry was not even a tropical cyclone …. ).

  218. David Smith
    Posted Sep 24, 2007 at 1:42 PM | Permalink

    Re #211 steven, the at-sea storms before 1945 we’re almost all detected by ships, the ones between 1945 and 1970 were a mix of aircraft and ships and the ones after 1970 were a mix of satellites, ships and aircraft. We can quantify the first group but the ship portions of the second and third groups are probably hopelessly entangled with satellite and aircraft.

  219. steven mosher
    Posted Sep 24, 2007 at 7:55 PM | Permalink

    218. Thx

  220. Posted Sep 24, 2007 at 8:52 PM | Permalink

    tetris, read #210, and read the NHC discussions about why Jerry was deemed tropical

    The upgrade of Jerry back to Tropical storm prior to killing it at 11 pm EST, is a rather confusing turn of events. However, the maximum sustained winds are so weak, that the ACE/PDI seasonal statistics are not affected at all. It is possible that the year-end reevaluation will assess the system differently.

  221. SteveSadlov
    Posted Sep 25, 2007 at 10:44 AM | Permalink

    Stirring the pot ….. here in the Pacific, we frequently experience cut off lows during the Sept – Nov period, which have a similar history to this one. No naming, no counting, it’s never even a consideration. But in the media hyped NATL basin, which is a, say it with me now, PROXY for KILLER AGW, the motto is, name it and claim it!

    http://en.wikipedia.org/wiki/2005_Azores_subtropical_storm

  222. SteveSadlov
    Posted Sep 25, 2007 at 11:05 AM | Permalink

    Not if but when the usual suspects add this year’s inflated count (we’re now at 11, using the most inflated interpretation) to the “trend” line of (spoken like megachurch preacher) “the RIIIIIiiiiiise of trrrrRRRRRopical CY-clones ….. as a result of KILler …. agw” those who study TCs and / or climate, and who actually have some ethics should have, at the ready, publications to smash into smithereens the basis for this inflated count. Yes, I am that cynical ….. in a good way. Been ’round the block a few times, and basically have a very dark view regarding the root mean squared ethical level of humans.

  223. Kenneth Fritsch
    Posted Sep 25, 2007 at 11:13 AM | Permalink

    Re: #218

    I think we should not pass off so easily the rationale used by Mann, Webster, Holland and others to use all the named storm data by claiming that passing ships not warned off by modern detection means would remain in the path of tropical storms and count them. To me this is like merely looking for any explanation for using the historical storm frequency data with minimal or no adjustments and without providing any details to justify it.

    The next step in the process is even more problematic for me and that is the referencing and cross referencing of this rationale in subsequent articles to seemingly give something, which appears to me to have been pulled out of a hat, some kind of scientific standing.

  224. tetris
    Posted Sep 25, 2007 at 11:21 AM | Permalink

    Re:220
    Ryan
    Maybe they’ll re-evaluate, but I somehow doubt it. What is named and counted is named and counted and thus will enter the stats. The media will be told that 2007 at the very least, was a regular TS/hurricane season. Much will be made of the two Cat 5 storms in one season as “proof” that AGW is causing if not more ‘canes, it’s causing heavier ones. The fact that the NHC counted 2 or 3 bogocanes will be sydiously ignored.

  225. Ryan Maue
    Posted Sep 25, 2007 at 12:04 PM | Permalink

    tetris, you are I are in agreement, as I conjectured in #210.

    It seems we have our answer about seasonal verification, from Michael Mann at Realclimate.com who is all to happy to take credit for prediction of the storm counts. The climate signal of these 40 knot storms that last

  226. Ryan Maue
    Posted Sep 25, 2007 at 12:05 PM | Permalink

    The climate signal of these 40 knot storms that last

  227. Ryan Maue
    Posted Sep 25, 2007 at 12:06 PM | Permalink

    my apologies: html issues: The climate signal of these 40 knot storms that last less than 24 hours cannot be in any way comparable to a full-fledged hurricane.

    “Response: Ike, those forecasts are for the total number of named storms. Three is the number just of the hurricanes so far. We’re at 10 total named storms (as many as we had all of last season) already, as of today w/ the new subtropical storm “Jerry”. And there are a few additional areas in the Atlantic that look like they could potentially develop over the next few days. We’re reasonably on track for own predicted 15 +/- 4 named storms, made prior to the storm season start, based in part on a predicted La Nina this fall/winter. Paper has since been published: Sabbatelli, T.A., Mann, M.E., The Influence of Climate State Variables on Atlantic Tropical Cyclone Occurrence Rates, J. Geophys. Res., 112, D17114, doi: 10.1029/2007JD008385, 2007, available as pdf here. -mike”

  228. tetris
    Posted Sep 25, 2007 at 12:36 PM | Permalink

    Re:227
    Ryan
    It’s all about quantity. Mann et. al. “15 +/- 4 named storms” represents a 37.5% margin of error. Other than in “Climate Science” that would cause raised eyebrows.
    The way the 2007 season is developing, we will end up with that number in the “marginal/did not qualify” category. The fact in terms of ACE values, we having been witnessing a series of flea farts notheless allows Mann and his fellow travellers to declare victory for their “forecast”. And, no doubt, make sure the media get their AGW version of the story.

  229. Kenneth Fritsch
    Posted Sep 25, 2007 at 2:32 PM | Permalink

    Re #228

    The fact in terms of ACE values, we having been witnessing a series of flea farts notheless allows Mann and his fellow travellers to declare victory for their “forecast”. And, no doubt, make sure the media get their AGW version of the story.

    I suspect that anyone from across the spectrum who can use the numbers to their advantage will and then in small print disclose some disclaimers. That is what prediction artists do. Those who were low, and again wherever they lie on the spectrum, will complain about the naming and disparity between ACE index performance and named storms.

    In this case I would agree with the latter while at the same time as a predictor of a higher number of TSs keep claiming, naming and exclaiming my great talents.

  230. SteveSadlov
    Posted Sep 25, 2007 at 2:47 PM | Permalink

    Name it and claim it ….. boyeeeeeee!

  231. Bill F
    Posted Sep 25, 2007 at 5:22 PM | Permalink

    Here is an idea…if they insist on naming these things, lets start the buzz about how global warming is making the average storm weaker over time. These myriad little 40kt pip squeaks should drag the average strength down nicely. I suspect that if you just added up the max windspeeds of all the storms and then divided by the number of storms, you would find a declining trend in “average max windspeed” over the “satellite era” of inflated counts. Wouldn’t it bother them to know that all their efforts to hype storm counts only succeeded in making a successful argument for weaker storms as a result of AGW?

  232. SteveSadlov
    Posted Sep 25, 2007 at 6:20 PM | Permalink

    There was a wonderfully maniacal and silly (in a good way) film starring the late Rodney Dangerfield during the 1980s titled “Back to School” in which he plays the character of a financially successful self made man. He does not have a degree and feels he missed out on not going to university in his youth. He decides to undertake an undergrad full time education in order to live this lost section of his life. Of course, being wealthy and completely worry free regarding the potential early career impacts of flunking out, he proceeds to party harder than to most dedicated frat boys. As a result, he ends up in a scenario where he must cram at the end of the school term in order to have any chance of passing. Let us turn our gage now to an analogous situation regarding the 2007 NATL Tropical Cyclone season. The window for named storms will soon close, and the final tally, be it one inclusive of a number of questionable features, or, some sort of more legitimate count, will be what it is, with no reasonable way to add to it. Given this challenge, I give you the NHC’s Rodney Dangerfield, end of term, good old college try:

    http://www.nhc.noaa.gov/

    (bring in sound of Oingo Boingo playing at frat party)”It’s a dead man’s party, who could ask for more?……”

  233. John M
    Posted Sep 25, 2007 at 6:20 PM | Permalink

    Bill F #231

    Actually, I think there is more basis for GW to cause more weak tropical storms than there is for it to cause Cat 3s to blow up to Cat 5s, or to cause “unprecedented” growth rates from TDs to hurricanes. See this analysis by David Smith here. (comment 16).

    Emanuel states in his FAQ that, for a 1C rise in sea surface temperature, hurricane wind speed should increase about 5%. He also states that other modeling shows a somewhat smaller increase.

    The worldwide tropical sea surface temperature has risen about 0.3C over the last 30 to 50 years.

    So, the predicted increase in wind speed is maybe 2 or 3 mph.

    A GW-induced increase of wind speeds of less than five mph could indeed lead to a greater number of very weak storms.

    The problem is that some folks couldn’t resist the PR value (and the nice movie graphic) of linking catastrophic hurricanes to GW. After all, what kind of call to arms is this: “Global Warming is causing more wimpy tropical storms!”

    Have no fear though. I’m sure that the above point will in fact be used to argue that this year’s storm history proves the link to GW, precisely because we have so many weak/borderline storms. In fact, we already have bloggers at Weather Underground wondering if we’ve set a record for number of named subtropical storms.

    You know what they say, any port in a storm.

  234. SteveSadlov
    Posted Sep 25, 2007 at 6:23 PM | Permalink

    gage s/b gaze (I guess I went to a few too many frat parties myself, in the day…. killed too many brain cells ….).

  235. steven mosher
    Posted Sep 25, 2007 at 6:34 PM | Permalink

    RE 223.

    Did anyone audit the captain’s log…. NO JOKES SADLOV.

    Seriously, the ships in the modern era have to have logs> I know it would be tedious
    but I would think one could do some kind of Apples to apples ( ship ID of storm pre satillite
    VERSUS ship ID of storm Post satillite) Comparison.

    Related stupid question. Before the advent of doppler, how did a ship on the Ocean
    measure Wind velocity ??? We tossed 5 cats in the air and 3 went overboard. Its a
    Cat 3.

  236. Posted Sep 25, 2007 at 6:55 PM | Permalink

    Re #231 Bill I’ve already done the analysis (in graph form here ). The red line shows weak storms while the blue represents total storms. I derived this using Schrodinger’s equation and a bottle of wine.

    At the current rate we’ll exhaust the Atlantic’s supply of hurricanes in early 2019.

  237. Kenneth Fritsch
    Posted Sep 25, 2007 at 7:40 PM | Permalink

    I am so damned excited about Jerry, Karen, and TD 13 that I am claiming before naming. A crammed storm at the end of the season is every bit as good as one in mid season. Did anyone ever take a discounted grade because they did an all nighter and scored well? I’ll get some respect yet.

  238. Posted Sep 25, 2007 at 7:59 PM | Permalink

    I believe that sailors in earlier years used the Beaufort scale, which converts sea state into a wind estimate. I’ve heard that the Beaufort technique works well.

    Typically ships tried to avoid bad weather. If the wind and wave direction indicated a storm (tropical or otherwise) then a ship used rules of thumb to steer away and avoid the worst.

    When one combines scarce ship coverage in the tropics, the infrequency of tropical storms, the small size of the high-wind area, the varying intensity of tropical cyclones over their life and a ship’s tendency to steer away from trouble, it’s no surprise that ships rarely sampled the strongest winds and likely missed some weaker, shorter-lived systems.

    And, even if a ship reported a high wind, the report had to be analyzed by the pre-WW2 meteorologist at the Weather Bureau. Was it a tropical storm or just a squally area? Is there a confirming report? Was the ship close enough to the center to know the storm’s max winds? Was the storm at its maximum intensity when the ship encountered it? Did two ships far apart encounter the same storm?

    A reprint of the October 1933 Monthly Weather Review’s Gale Report is here . This is a partial list of at-sea high wind reports for the Atlantic in October 1933. I’ve put a red dot by the factors which the meteorologists probably used to judge if the wind was from a tropical cyclone and how close the ship might have been to the center. It is detective work involving conjecture.

    While a judgment could be wrong in either direction, my impression is that they had rather high standards before calling an at-sea storm a tropical cyclone and in estimating the max winds. I recall reading something years ago to that effect, probably in an old book: I’ll look for the reference.

  239. Posted Sep 25, 2007 at 8:11 PM | Permalink

    Re #237 Kenneth I’m getting excited too. If we count TD13 ( a good bet) then we’re at 11 with a little over two months to go. Surely there are a few more junk storms in our future.

    And, if we need an extra storm, we can use Michael Mann’s sleight of hand and include subtropical storm Andrea in our count.

  240. K
    Posted Sep 25, 2007 at 8:21 PM | Permalink

    Karen at least looks legitimate. I think the NHC prefers that Jerry not be discussed.

    About four days ago I said we might get to October with no more names. Immediately we had two.

    Per #236: Buy storms, short hurricanes.

    #235. No problem for ships to carry wind gauges. They probably weren’t very accurate but that wasn’t important. Sailors also knew various subjective scales I never learned.

    I did learn the Beaufort Scale almost sixty years ago. It was based upon observing leaves blowing, difficulty walking, large trees being toppled, etc. so wasn’t for use at sea.

  241. Kenneth Fritsch
    Posted Sep 25, 2007 at 8:28 PM | Permalink

    RE: #238

    Typically ships tried to avoid bad weather. If the wind and wave direction indicated a storm (tropical or otherwise) then a ship used rules of thumb to steer away and avoid the worst.

    Sorry, David, but I have never seen your theory in the peer-reviewed literature. On the other hand, the theory that passing ships not warned away by modern equipment found these storms can be found referenced in several peer-reviewed papers. I know your theory appears to be more logical, but peer-reviewed is peer-reviewed.

  242. SteveSadlov
    Posted Sep 25, 2007 at 8:49 PM | Permalink

    Kenneth Fritsch – do a few beer bongs and you’ll get my respect! :lol:

  243. Posted Sep 25, 2007 at 8:51 PM | Permalink

    Re #241 :)

    Beaufort Scale

    Interesting map of ship weather observations in September 1997 ( link ). Note the lack of coverage on much of the world, including the tropical Atlantic. Fifty years earlier the coverage was worse, much worse.

  244. D. Patterson
    Posted Sep 26, 2007 at 2:32 AM | Permalink

    Kenneth Fritsch says:

    September 25th, 2007 at 8:28 pm
    RE: #238

    Typically ships tried to avoid bad weather. If the wind and wave direction indicated a storm (tropical or otherwise) then a ship used rules of thumb to steer away and avoid the worst.

    Sorry, David, but I have never seen your theory in the peer-reviewed literature. On the other hand, the theory that passing ships not warned away by modern equipment found these storms can be found referenced in several peer-reviewed papers. I know your theory appears to be more logical, but peer-reviewed is peer-reviewed.

    If there are no such peer reviewed journal articles, perhaps it can be explained by the failure of the academics concerned to demonstrate the commonsense knowledge and expertise of a licensed mariner and deck officer who uses the Buy Ballots Law.

    3. A passenger vessel in 24 degrees north and 73.5 degrees west is bound for New York from Kingston (Jamaica) at a speed of 22 kts. and is working to a very tight schedule.

    A hurricane has been reported to be 120 miles to the eastward and moving in NW’ly direction.

    3. (a). Explain how the Master may ascertain the vessel’s position relative to the storms path by onboard observations.

    • Master should heave to and take observation of true wind direction.

    • Once the direction and force of wind have been ascertained, he should employ “BUY BALLOTS LAW” to estimate the storm centre and this would provide a relative bearing of the storm centre, i.e. in the northern hemisphere and with the observer facing the wind, take a bearing 8 compass points to the right and take a bearing 12 compass points to the right. The centre of the storm lies between these two bearings.

    • The force of wind being experienced by the vessel would also indicate the range of the ship from the storm, i.e.

    150 miles from centre — 7 force wind;

    125 miles from centre — 8 force wind;

    75 miles from centre — 10 force wind.

    • The semicircle in which the vessel is situated by observation of the true wind shift;

    in the Northern Hemisphere,

    if the wind is veering, the vessel is in Dangerous Semicircle (DSC)

    if the wind is backing, the vessel is in Navigable Semicircle (NSC)

    • Vessel’s position would also be indicated by direction of swell and associated weather, satellite pictures and facsimile charts.

    3. (b). If these observations confirm that the vessel is in the advance semicircle of the storm state, making reference to the vessel schedule, the action that the Master should take to expediate the voyage. A chartlet of the area is provided for information only.

    If the vessel’s observation was ahead of trough line,

    • if in path of dangerous quadrant, place wind on starboard bow and proceed at best speed, progressively altering course to starboard as wind veers.

    • if in path of navigable semicircle, place wind on starboard quarter and proceed at best speed, progressively altering course to port as wind seeks.

    This action would put the vessel close to islands to south and may be necessary in order to avoid being caught on the lee shore.
    http://www.geocities.com/mahzarine/navtheory.htm

    Mariners and navigators have traditionally been aware of the sky condition, winds, and sea state associated with gales and tropical storms; and they have employed such avoidance strategies as the Buy Ballot Law to determine as a rule of thumb the best course to take for avoidance of such hazardous weather. Peer reviewed papers are not needed to be aware of such well known historical maritime laws, customs, and practices.

  245. Kenneth Fritsch
    Posted Sep 26, 2007 at 9:03 AM | Permalink

    Re: #244

    D. Patterson, what you and David Smith says makes sense to me, but unfortunately it has not appeared in the peer-reviewed literature and need I remind you that peer-reviewed is peer-reviewed. Normally when I see theories that are not presented in the peer-reviewed literature I instinctively avert my eyes and attention, but since getting so wrapped up in tropical storm science I have developed a bad habit of reading theories not in the peer-reviewed literature. This state of affairs tends to confuse me and could well lead me astray from what the good book says – which in this case is the peer-reviewed literature.

  246. D. Patterson
    Posted Sep 26, 2007 at 9:14 AM | Permalink

    Re: #245

    Often times the problem lies with the choice of peers, especially any peers who are published and are ignorant of the knowledge common to the experience of the unlettered, the unheard, and the untouchable.

    Sometimes the peerage make efforts to ensure those persons whom they wish to deny credibility are never permitted to become members of the peerage.

  247. Kenneth Fritsch
    Posted Sep 26, 2007 at 9:19 AM | Permalink

    Re: #242

    Steve S, I had to either ask one of my sons or go to Wikipedia just to determine what a beer bong was. I thought it might be smoking pot through a container of beer. At Wikipedia I got a whole dissertation on the techniques and science of beer bonging. We had binge drinking when I was in college but I do not remember it being a sport. Anyway, if I told you I can occasionally drink 2 martinis in a setting, would I get some respect? I continue to learn at CA even if the content is not always climate science.

    http://en.wikipedia.org/wiki/Beer_bong

  248. Cliff Huston
    Posted Sep 26, 2007 at 9:56 AM | Permalink

    RE: 245
    Kenneth,

    American Practical Navigator, Nathaniel Bowditch, LL. D., Deffense Mapping Agency Hydrographic Center.

    You may argue about the peer group, but not about whether the above is peer-reviewed literature. Since first publication in 1802, you would be hard pressed to find any ship’s master that didn’t own and consult Bowditch on a regular basis.

    My copy is the 1977 edition and the relevant discussion was found in section 3910, on page 903.

    Regards,

    Cliff

  249. SteveSadlov
    Posted Sep 26, 2007 at 11:27 AM | Permalink

    “Don’t run away
    It’s only me…..”

    http://www.accuweather.com/news-story.asp?partner=accuweather&traveler=0&article=0

    (Image of Danny Elfman suddenly popping up like a Jack In the Box)

  250. D. Patterson
    Posted Sep 26, 2007 at 11:27 AM | Permalink

    See especially the illustrations in Chapter 36 and note how mariners have long been made aware of the ocean basins and seasons in which hurricanes, typhoons, and tropical storms were to be avoided.

    The Online American Practical Navigator or “Bowditch
    as published by the U.S. Department of Defense
    Brought to you by MarinePlanner.com
    [….]
    CHAPTER 36. TROPICAL CYCLONE. CAUSES AND DESCRIPTION OF TROPICAL CYCLONES.
    On his second voyage to the New World, Columbus encountered a tropical storm. Although his vessels suffered no damage, this experience proved valuable during his fourth voyage when his ships were threatened by a fully developed hurricane. Columbus read the signs of an approaching storm from the appearance of a southeasterly swell, the direction of the high cirrus clouds, and the hazy appearance of the atmosphere. He directed his vessels to shelter. The commander of another group, who did not heed the signs, lost most of his ships and more than 500 men perished.
    [….]
    AVOIDING TROPICAL CYCLONES
    […..]
    3608. Approach And Passage Of A Tropical Cyclone
    3609. Locating The Center Of A Tropical Cyclone
    [….]
    According to Buys Ballot’s law, an observer whose back is to the wind has the the low pressure on his left in the Northern Hemisphere, and on his right in the Southern Hemisphere. If the wind followed circular isobars exactly, the center would be exactly 90° from behind when facing away
    from the wind.
    [….]
    3611. Maneuvering To Avoid The Storm Center

    http://www.marineplanner.com/bowditch/bowditch.cfm

    http://www.marineplanner.com/bowditch/chapt-36.pdf

  251. Cliff Huston
    Posted Sep 26, 2007 at 11:58 AM | Permalink

    RE: 249, 251

    The section I was referring to in #249 would be section 3609 in the on-line edition, but yes all of chapter 36 is worth reviewing. Also see the on-line preface titled Nathaniel Bowditch for background and publication history.

    Cliff

  252. Cliff Huston
    Posted Sep 26, 2007 at 12:48 PM | Permalink

    RE: 251 – continued

    Also, addressing David Smith’s points in #238 – see Bowditch chapter 37 and the National Weather
    Service Observing Handbook No. 1, Marine Surface Observations, which can be found here:

    http://www.nws.noaa.gov/om/marine/handbk1.pdf

    Cliff

  253. SteveSadlov
    Posted Sep 26, 2007 at 1:11 PM | Permalink

    For eveyone’s viewing and listening enjoyment …

    I think Rodney’s a martini man …. got to watch closely to pick up the image …

    I am thinking through what I would want to include in my new concoction, the Hyper Hurricane Martini ….

  254. SteveSadlov
    Posted Sep 26, 2007 at 1:16 PM | Permalink

    Or perhaps, martini glass abuse …. just like classification abuse? …..

  255. Kenneth Fritsch
    Posted Sep 26, 2007 at 4:00 PM | Permalink

    D. Patterson and Cliff Huston you do not need to convince me. You have to convince the peer-reviewers. It is written in the peer-reviewed literature that passing ships not warned detect. Now, Chris Landsea wrote in the peer-reviewed literature that, in effect, other observations strongly indicate that that theory is indefensible – but did not say it directly. Thus the peer-reviewed literature will no doubt continue to reference the “not warned equal detect” theory and without disclaimers. Since the peer-reviewed literature is the bible for so many, who come here to defend climate science, we need to change the peer-reviewed literature, because – lets say it all together now – peer-review is peer-review.

  256. SteveSadlov
    Posted Sep 26, 2007 at 6:13 PM | Permalink

    ITCZ AXIS IS CENTERED ALONG 9N13W 11N20W 6N30W 12N39W 4N55W.

    The ITCZ is definitely moving south and will soon be in the SH. After the blob of thunderstorms in the Bay of Campeche (which may be a relic of an earlier tropical wave) gets hyped, named and claimed, then fizzles out, there will be a declining opportunity for any real ITCZ originated features to track far enough north to make it around the minor cape of land north of the Amazon Delta or track far enough west to avoid getting sheared over the open Atlantic (but hey, this is the National Hysteria Center, who ever let sheered non closure get in the way of naming and claiming!). The count padders shall have to rely completely on “home grown” features and ones of overt Polar Jet origin for their count.

  257. Posted Sep 26, 2007 at 8:08 PM | Permalink

    For fun, here’s an example of a likely-missed tropical cyclone.

    The year is 1930 and the month is October. The records show no October tropical cyclones.

    However, when I read the October issue of the Monthly Weather Review’s article on the North Atlantic Ocean ( link ), I find this excerpt:

    From the 15’th to the 18’th low pressure prevailed in the southwestern part of the Gulf of Mexico, apparently being part of a general depression covering lower Mexico and adjacent parts of both the Pacific and the Gulf. On the morning of the 19’th a center developed on the Gulf Coast and during the day moderate to strong gales were experienced by vessels in the vicinity. However by the morning of the 20’th the disturbance had lost energy and on the 21’st the entire Gulf, except the Bay of Campeche, was covered by the southern part of an extensive continential area of high pressure.

    The Ocean Gales and Storms summary in the same issue of MWR reports that, on the 19’th, the SS Nubian experienced 50 knot winds from the WSW in the Bay of Cammpeche, a 29.45 inch barometer and a wind shift (SW-W-N) consistent with a cyclone center passing to its east.

    My interpretation is that a strong tropical storm or weak hurricane passed to the east of the Nubian (placing the Nubian on the weak side of the storm) and the storm eventually moved south and west into Mexico. I do not know of an alterate explanation for the observed weather.

    However, the meteorologists of the day simply placed the event into the “depression” category, a category which is not counted, probably because they wanted a lower barometric reading or additional ship observations as confirmation of a tropical system.

  258. Posted Sep 26, 2007 at 8:55 PM | Permalink

    Steve S I thought of you when I read this statement on Tropical Storm Karen a few minutes ago:

    A PEAK SURFACE VALUE OF 62 KT REPORTED TWICE…NOT QUITE HURRICANE
    STRENGTH. HOWEVER…GIVEN THE DEGRADED SATELLITE APPEARANCE FROM
    EARLIER TODAY…KAREN WAS ALMOST CERTAINLY A HURRICANE THEN…AND
    THIS LIKELIHOOD MAY BE REFLECTED IN THE FINAL BEST TRACK FOR THE
    SYSTEM.

    So, they found almost-hurricane winds tonight but not quite. They are of the opinion that, since the clouds looked better earlier today, it may have been a hurricane then, even though there were no supporting measurements. Months from now, when the reanalysis is done, they may declare Karen to have actually been a hurricane, based on earlier cloud appearance.

  259. SteveSadlov
    Posted Sep 26, 2007 at 9:23 PM | Permalink

    RE: #258 – Yep, compare the mentality you characterized in this post, with the one you characterized in #257. There has definitely been a change. Caution and insistence of corroboration have been thrown out the window. Looking forward to a short test run on my “NHC” blog, Nov – Dec. Then, in Jan, I will go live, and describe 2008 from end to end, in NPAC. I will use identical de facto operational definitions versus what we are witnessing in 2007 in NATL. This is going to be amusing!

  260. K
    Posted Sep 26, 2007 at 9:49 PM | Permalink

    #258. I picked up on the ‘was almost certainly’ hedge too. They ‘almost certainly’ will make it a hurricane later.

    Lately some NHC advisory discussions have used rather forced wording to insist on higher winds. I haven’t followed NHC announcements long enough to judge whether this is normal.

    #259. I look forward to your blog.

  261. D. Patterson
    Posted Sep 26, 2007 at 10:31 PM | Permalink

    Re: #259

    The Winds of Change at the NHC: a perfect storm of controversy

  262. Kenneth Fritsch
    Posted Sep 27, 2007 at 10:03 AM | Permalink

    Re: #255

    Since the peer-reviewed literature is the bible for so many, who come here to defend climate science, we need to change the peer-reviewed literature, because – lets say it all together now – peer-review is peer-review.

    The part of my post up to the final sentence is my direct point on the peer-reviewed literature in the case of the “passing ships” theory. In the last sentence, excerpted below, I want to be clear to those not familiar with my thinking that I am being satirical. Peer-review is at best a filtering process that is performed by people and it is those people who determine how well and how objectively it is performed. It is a time honored and nearly universally accepted method that will not be changing soon, but that only means that other venues like blogs can take on these issues where the peer-review process fails, or at least appears to fail to those of us who may be looking at the issue from a different perspective. That is why I enjoy the CA blog and discussions like those appearing in this thread.

    My only suggestion is that we take the time to understand in more detail what it is that those with differing POVs are actually saying and why they are saying it.

  263. David Smith
    Posted Sep 27, 2007 at 12:45 PM | Permalink

    Kenneth I just read the Sabbatelli/Mann paper and smiled when I saw them quote Emanuel’s dumb-ships hypothesis as a “credible argument” that validates historical storm counts. I go back and forth wondering if they really believe this stuff or are they just being argumentative. I can’t decide.

  264. SteveSadlov
    Posted Sep 27, 2007 at 7:50 PM | Permalink

    This one is beyond the pale:

    http://www.nhc.noaa.gov/refresh/graphics_at3+shtml/204025.shtml?swath#contents

    I see no red here. A true bogocane.

    The boy who cried wolf. At some point, people will start to ignore the NHC’s warnings. A disaster will be inevitable.

  265. Posted Sep 28, 2007 at 9:40 AM | Permalink

    Kenneth we’re getting more help to reach our storm prediction total, with the designation a little while ago of another tropical depression (#14 for the season).

    The forecast is here:

    INITIAL 30 KT
    12HR VT 35 KT
    24HR VT 40 KT
    36HR VT 40 KT
    48HR VT 35 KT

    If true, that gives us a named storm (Melissa) with an ACE of 1.1 (average ACE is 10). That would be a storm count of 12 to-date.

    The

  266. SteveSadlov
    Posted Sep 28, 2007 at 11:48 AM | Permalink

    The final Dangerfield-esque end of term cramming by the NHC may yet get us to Alpha!

  267. steven mosher
    Posted Sep 28, 2007 at 12:32 PM | Permalink

    When will they start using rapper names for hurricanes

  268. Kenneth Fritsch
    Posted Sep 28, 2007 at 1:56 PM | Permalink

    David, I very much like your naming of the theory as “the dumb ships theory” and will commence to used it from now on.

    I am really getting excited about the named storm counts and my ability to forecast a more “sensitive” naming process and thus more named storms. It is like calling the stock market turns not by the underlying fundamentals but by people’s (over)reactions to them.

  269. Sam Urbinto
    Posted Sep 28, 2007 at 3:13 PM | Permalink

    Hurricane Kewl G

  270. Posted Sep 29, 2007 at 6:45 AM | Permalink

    Tropical Storm Missy was named this morning, giving us 12 tropical cyclones for the season. :)

  271. Kenneth Fritsch
    Posted Sep 29, 2007 at 6:59 AM | Permalink

    Missy, Missy glad we didn’t Missy.

  272. Posted Sep 29, 2007 at 7:43 AM | Permalink

    Kenneth this afternoon my neighbors and I will arrange our leaf blowers to create a cyclonic leaf whirl, in the hopes of a satellite seeing it. Maybe we’ll have “Noel” by sunset, our 13’th tropical cyclone of 2007.

  273. D. Patterson
    Posted Sep 29, 2007 at 7:51 AM | Permalink

    Re: #263

    It may very well be a testable hypothesis. The marine surface weather observations should supply a sequence of periodic and special weather observations that reveal the position reports of the vessels and whether or not the vessels veered away from a storm as it was detected.

  274. Posted Sep 30, 2007 at 8:47 AM | Permalink

    Tropical Storm Melissa is gone. It last a grand total of 30 hours and generated an ACE of 0.65 (average storm has an ACE of 10).

    Noel may form near the Bahamas early next week, which would be number thirteen for the season (assuming that it is tropical).

  275. Kenneth Fritsch
    Posted Sep 30, 2007 at 8:55 AM | Permalink

    Re: #274

    Missy, Missy, you will not be Missy.

  276. Bob Koss
    Posted Sep 30, 2007 at 9:15 AM | Permalink

    The ease with which they’re willing to put a name to these rain storms just ends up making the database more inaccurate. I expected it when I made my WAG at the beginning of the season. But not to such an extent.

    Over the long term the ratio of hurricanes:tropicals has been 8:5. This year it’s 4:8. Only if they don’t name any more will my guess be close. I think I said 5:7 expecting them to name a couple cheap ones.

    Just goes to show why you shouldn’t bet against the house. :)

  277. Posted Sep 30, 2007 at 10:30 AM | Permalink

    One thing I’ve learned about hurricane climatology over the last year is that it’s not that important to understand the limitations of data. This has been liberating, as it frees me to explore a universe of topics.

    My first topic is US tornadoes and I’ve been horrified by what I’ve found ( link ).

    Once I complete my surface temperature data for the Main Development Region (Kansas) I plan to do a climateaudit blog on the subject.

  278. Kenneth Fritsch
    Posted Sep 30, 2007 at 3:54 PM | Permalink

    I refuse to use the emoticons so I hope you all know that I think the forecasting game is pretty much just that – a game. I like to brag on this thread like a forecaster got lucky and believe me when I use the term lucky. I suspect that the forecasters, be it the empirical ones or the dynamical ones, can have some skill when they have all the variables together within a short period from the event. When it comes to predicting the variables months ahead I have yet to see any statistical skill from any forecaster. One, of course can also play the cyclical nature of the tropical storms to an advantage but that mostly works only over a multiple year period.

  279. Posted Sep 30, 2007 at 4:52 PM | Permalink

    Re #278 I think a forecaster can do somewhat better-than-chance by noting the ENSO state and whether the AMO is in its active phase (= higher SST and weaker Caribbean TUTT). The forecaster’s options are normal, below-normal and above-normal. That’s about it. This business of forecasting numbers simply lends an air of precision that is unsupported by the facts.

    I find it interesting that Mann wrote a paper recently which promotes an empirical approach. One day I’ll read it in detail and compare it to Gray’s approach.

    I’m thinking that our contest/spoof may deserve a modification, with two ways to win. The second way would convert each storm count forecast into an ACE forecast by multiplying the forecasted count by 10 (a typical ACE per storm) and then see who comes closest to the actual 2007 ACE. For instance, someone who forecast 7 storms would be assigned an ACE of 7×10=70, and that would be compared to the end-of-season ACE (ACE as of September 30 is 61). This helps adjust for all the junk storms we’ve had this year.

    Of course we’ll keep the straight count contest too, since you and I may continue to get lucky :)

  280. SteveSadlov
    Posted Oct 5, 2007 at 12:32 PM | Permalink

    Tropics have gone very quiet. ITCZ is at or below 10 N everywhere. Although y’all back East would say it’s Indian Summer right now, here out West it’s already winter. Sometime soon, this cold air will interact with all the warm air back east and a major mid latitude disturbance to the Polar Jet will no doubt ensue. That will be interesting. There may be no more named storms, even bogus ones, the rest of the year in NATL. We’ll see ….

  281. SteveSadlov
    Posted Oct 5, 2007 at 12:34 PM | Permalink

    RE: #279 – 90.

  282. Posted Oct 5, 2007 at 1:10 PM | Permalink

    Greg Holland offers a 2007 Powerpoint presentation on hurricanes, located here . It’s mostly a repeat of the earlier Holland Webster paper but there is one interesting map on which I’ll comment.

    The map is here , and comes from slide 21. It’s a map which is a bit hard to get into focus at first glance. It is a tropical Atlantic map which shows historical changes in where Atlantic tropical cyclones were first detected. Storms are put into two buckets (1906-55 and 1956-2005) and the geographical change in detection is plotted. Hot colors mean more storms were detected there while cool colors mark regions where fewer storms were first detected.

    To help communicate the map I’ve placed its major areas of change on this map . The red areas show where more storms were first detected in the last fifty years while the blue rectangles show where fewer storms were first detected.

    I believe that Holland’s contention is that detection point and genesis point are synonymous and that the map shows a shift in genesis into the low-latitude Atlantic (“A”) and into regions along the US coast (“B” and “C”). The thinking is that warmer SST over the 20’th Century shifted genesis farther east, as that region warmed. Also, I presume that the increases along the US coast are attributed to warmer SST converting more marginal systems into tropical cyclones.

    The areas of reduction (“D” and “E”) are presumably “robbed” of their seedlings by development farther east.

    The alternate view is that genesis point and detection point are not synonymous. In this view the reason that “A” has increased and “E” had decreased is simply because satellites and aircraft have detected cyclones earlier, when they are in the eastern Atlantic, and have also detected the weaker briefer systems in the eastern Atlantic which would have been missed before satellites and aircraft. The sharp transition from “A” to “E” shows the decreased dependence on detection by the islands of the Lesser Antilles.

    The alternate view sees the increased detection along the US coast as increased detection/classification of weak systems due to the buoy network and shore-based radar network, the ability of satellites to better detect the weak frontal-type cyclones and the NHC’s tendency to err on the side of caution when disturbances are near the US. The alternate view would also note that SST near the US has increased only modestly, if at all, in “C” and “D” in the periods under study.

    The decrease in region “D” is actually one where Holland and I might find some common ground. The decrease may be real (due to seedling “robbing” or atmospheric changes) or it may be the result of detection of weak systems farther east. The change is not large but it is distinct. It’s one to ponder.

    (There is also one small area around 65W and 30N which shows an increase in first detection. I did not include that region because Holland included subtropical cyclones (=not tropical) in his count and the 65W30N is a region of such subtropical cyclones. I’d like to see his plot without the subtropical systems before considering that region.)

  283. steven mosher
    Posted Oct 5, 2007 at 1:18 PM | Permalink

    RE 280. Snow in Chester CA last night

  284. SteveSadlov
    Posted Oct 5, 2007 at 1:21 PM | Permalink

    RE: #283 – Is that an all time record for earliest onset of climatic winter for that location?

  285. Posted Oct 5, 2007 at 1:57 PM | Permalink

    RE #282 I also found Holland’s projection of Atlantic storms to be interesting ( link to slide 42 ).

    I presume the base period is the last decade or so of increased activity (1995-present).

    It looks like a forecast of “about the same or small increases” except for Caribbean landfalls and I presume it incorporates his beliefs on AGW/SST offset by the declining phase of the AMO. It is remarkably unapocalyptic, which surprises me.

  286. steven mosher
    Posted Oct 5, 2007 at 2:10 PM | Permalink

    RE 284. I dont know. The earliest I’ve seen snow was Thanksgivig a few years back.. My real estate guy
    just caled and asked if I wanted to winterize!!! ( I typically do it in November)

    AND, chester ( almanor) is a BANANA BELT!

  287. steven mosher
    Posted Oct 5, 2007 at 2:19 PM | Permalink

    RE 284.

    I think it should be in record territory.

    http://www.wunderground.com/US/CA/Chester.html

    Norcal has been decidedly cool this year… except perhaps for the 4thJuly, Lucky me I was in
    Madera. SteveS you would not believe what is happening in terms of build up around 99 North of Madera.

  288. Bob Koss
    Posted Oct 5, 2007 at 2:37 PM | Permalink

    Hven’t read the presentation yet. But I see it was given June 2007 yet he didn’t include 2006 data which was certainly available. Makes me think he tends to like having the worst possible end point on which to base his conclusions.

    I think it can all be laid off to detecting genesis at lower wind speeds due to satellite/buoy observations.

    I’ll work up a basin graphic of first track wind data over the weekend.

  289. SteveSadlov
    Posted Oct 5, 2007 at 2:39 PM | Permalink

    RE: 286 – Also, FYI, an isolated cell (given the dry origin of the system in the arid part of the Yukon…) dusted Fremont Peak, a sub 4000 footer in San Benito County, with snow, over night. At least in my life time, the earliest I’ve ever seen snow on peaks of that height in this part of California was Thanksgiving. I have never seen any snow on nearby peaks (including the highest over 4K ones such as St. Helena and Hamilton) at any time in October. Back in 2004, when the ski areas opened October 20th, there was no snow on any of these peaks, snow level was about 6K. This is truly unprecedented in my lifetime.

  290. Posted Oct 5, 2007 at 2:53 PM | Permalink

    Re #287 That will be nice!

  291. steven mosher
    Posted Oct 5, 2007 at 2:59 PM | Permalink

    RE 289. Snow at 4K feet at this time of year is “climate change”

  292. Bob Koss
    Posted Oct 5, 2007 at 3:37 PM | Permalink

    Ahhh. What the heck. Decided to do them up while still at the computer.
    Here are the graphics of discovery wind speeds for all storms. In the earlier period most storms weren’t discovered until they were already at tropical storm strength. Now they pick them up while they’re a low or a depression.
    I used the same time frames as Holland.

    Color code for the graphics.
    Green = 20 kt or less
    Blue = 25 kt
    Red = 30 kt
    Yellow = 35 kt or higher

    Here they are.
    1906_1955
    1956_2005

  293. SteveSadlov
    Posted Oct 5, 2007 at 3:51 PM | Permalink

    RE: #290 – You raise a good point. For all of my post-toddler life up until winter 98, with the exception of the massive 76 -77 La Nina / Drought, late 1990 – early 91 freeze, and, killer El Ninos 82 – 83 and 97 – early 98, “normal” conditions meant a “Indian Summer” period for most of September, and at least until right before Halloween, some years going until mid November, at least here in the coastal and near coastal zone. Then a cool winter but nothing to write home about, lasting until March. Then the normal warm to hot spring grading slowly into the typical summer pattern of alternating onshore push and slight offshore events. When we got the bad early winter in 1998, I viewed it as an outlier. When we got the early winter (late October) in 2000, probably an outlier. Then spring started to disappear, due to longer winters. Then, in 2004, another early winter (mid Oct). Still, terrible springs. 2005, another fairly bad winter with spring low elevation snow events. 2006, warmmmmmmmest in xxxxxxx, but really it was just “fall” type offshore in July. Early fall onset, then a cold, cold (but too dry) winter with late season low snow again in spring 07. Coolish summer. Fall started at the end of July. Got our “Indian Summer” in August. Now, here we have the earrrrrrrliest winter everrrrrrr. Seriously, I am now begining to wonder about outliers versus shifts.

  294. Posted Oct 5, 2007 at 4:26 PM | Permalink

    Re #292 Nice-looking plots, Bob!

    If Holland did apples-to-apples mapping then he plotted the locations where winds first reached 35 knots. Depressions would not count, as their records are a creation of modern times and would skew things eastward and southward.

    An interesting aspect of your maps is found in the eastern Caribbean between 62W and 72W. That area is almost void of dots and is well-known for being a region where cyclones rarely form. The void is believed to be due to proximity to South America and to the presence of an upper-air feature which creates wind shear. Or, maybe it’s the Bermuda Triangle :)

    On a slightly different subject I noticed that Holland’s presentation was in Aspen. They seem to have their get-togethers in Aspen and Bali while we non-climatologists meet in Detroit and Allentown. Drat.

  295. Posted Oct 5, 2007 at 9:24 PM | Permalink

    As mentioned in #282, the Holland map shows increased tropical cyclone “genesis” in several regions of the Atlantic ( see this map ). Two regions (“B” and “C”) are near the US.

    The common AGW hypothesis is that higher sea surface temperatures (SST) lead to greater storm formation. So, have these regions experienced higher SST?

    The SST for the Gulf of Mexico (“B”) is here . This covers all months, not just the hurricane season, but the annual and hurricane season temperaures should be well-correlated.

    The SST for waters near the southeast US (“C”) is here .

    Warming, if any, is thanks to the low temperatures in the first couple of decades. Temperatures are only now returning to the levels of the 1930s.

  296. Bob Koss
    Posted Oct 6, 2007 at 12:14 AM | Permalink

    Dave,

    Your nice SST charts don’t seem to allow him to rule out cyclical variation and changes in observation quality. I think he just wanted to say something that might possibly be ominous.

  297. Bob Koss
    Posted Oct 6, 2007 at 12:44 AM | Permalink

    Here are a couple charts that demonstrate how observational ability has increased markedly. Seems to me one would have to find a way to mathematically compensate for this before reliably being able to claim or project unnatural storm variations. Satellite era alone is too short to be meaningful and the observational quality has change considerably over longer periods.

  298. hillrj
    Posted Oct 6, 2007 at 1:05 AM | Permalink

    re. 277 David Smith horrifying tornado graph
    Any follow up? Or is it in another thread?

  299. Brooks Hurd
    Posted Oct 6, 2007 at 2:35 AM | Permalink

    The grape harvest in the Central Coast is a bit later than normal.

  300. John M
    Posted Oct 6, 2007 at 9:45 AM | Permalink

    David Smith #294

    Ouch. Dagger to my heart! I was born in Detroit and now live in Allentown. If you diss Bloomington, IN next, you’ll be three for three!

    But back to hurricanes. I saw this on the Jeff Masters Weatherunderground blog. Someone was wondering about the low number of NH cyclones, and received this e-mail from Masters.

    FROM: JeffMasters FAVORITES BLOCKED
    TO: MichaelSTL
    DATE: 2007-10-01 20:02:18 (8:02 PM CDT)
    SUBJECT: Re: Cause of unusually low NH tropical cyclone activity?

    Hi, one of those blogs I haven’t written yet talks about a paper published this past year that shows a net decrease in global TC numbers due to global warming (except in the Atlantic). This was a computer model study where they doubled CO2. I don’t have any other speculations beyond that. Once the tropics slow down I’ll discuss some interesting papers published recently on global warming/hurricane activity.

    Jeff

    And here I’ve been caterwauling about weak tropical storms being the next definitive link between climate change and cylones.

    John M (not John M.)

  301. M. Jeff
    Posted Oct 6, 2007 at 10:45 AM | Permalink

    re: hillrj, October 6th, 2007 at 1:05 am, “re. 277 David Smith horrifying tornado graph, Any follow up? Or is it in another thread?”

    Graph at http://www.hprcc.unl.edu/nebraska/us-tornado-deaths1916-2005.html shows dramatic decline in U.S. annual tornado deaths during the 1916 to 2005 time frame. Annual death rate inversely proportional to CO2 levels?

  302. Posted Oct 6, 2007 at 10:49 AM | Permalink

    Re #297 Bob I’ve added your top chart to my permanent collection. It says a load of things about changes in detection, record-keeping and classification practices over the 20’th Century.

    I’m intrigued by the change circa 1915 and I’ll take a look back in the records to see if some cause jumps out.

  303. Posted Oct 6, 2007 at 11:00 AM | Permalink

    Re #298 rj it’s under construction.

    Big Oil (BO) discovered the research into the indisputable AGW/tornado connection and they’ve been trying to frustrate my efforts. I’ve lost valuable time due to jousting with jesters and, while I cannot prove the jester’s funding source, the situation sure smells like BO.

    Note the similarity in this tornado chart and this Exxon stock price chart . Both rise. Coincidence? I think not.

  304. Posted Oct 6, 2007 at 11:54 AM | Permalink

    Re #300 I lived near Detroit (on the Canadian side of the border), enjoyed the town and have friends in the area, so for me a convention in Detroit would be a treat!

    A warmer world would see conflicting trends in storm numbers. My guesses are that greater stability and wind shear would favor fewer storms while longer seasons, greater areas of warm water and increased low-level water vapor would favor more storms. Where things balance out is anyone’s guess.

  305. Posted Oct 6, 2007 at 12:50 PM | Permalink

    Re #301 M Jeff thank you for sharing the chart showing trends in human fatalities from tornadoes. It is laudable that warning systems have saved human lives.

    However, we humans (who, after all, are responsible for the tornado increase) must not forget Nature’s Most Fragile, whose victimization has grown with the CO2/tornado increase.

    I provide a revised plot which tells the fuller story and I hope leads to deep reflection by all. The SUV/CO2/tornado/crow link is real and stark.

  306. Posted Oct 6, 2007 at 3:21 PM | Permalink

    The last NHC outlook reads:

    000
    ABNT20 KNHC 062108
    TWOAT
    TROPICAL WEATHER OUTLOOK
    NWS TPC/NATIONAL HURRICANE CENTER MIAMI FL
    530 PM EDT SAT OCT 6 2007

    FOR THE NORTH ATLANTIC…CARIBBEAN SEA AND THE GULF OF MEXICO…

    …………………………………………………………….
    ……………………………………………………………

    A NON-TROPICAL LOW PRESSURE AREA LOCATED ABOUT 525 MILES
    NORTH-NORTHEAST OF THE AZORES HAS ACQUIRED SOME SUBTROPICAL
    CHARACTERISTICS DURING THE DAY. HOWEVER…THE SYSTEM IS MOVING
    QUICKLY NORTHWARD OVER COOLER WATERS AND FURTHER DEVELOPMENT IS NOT
    ANTICIPATED.

    ELSEWHERE…TROPICAL CYCLONE FORMATION IS NOT EXPECTED DURING THE
    NEXT 48 HOURS.

    $$

    FORECASTER BLAKE

    525 miles NNE of the Azores?

    I thought it was a mistake. Look at this Meteosat loop

    Steve Sadlov, are you ready for the first TC formation west of Ireland next year? Courtesy of NHC.

    BY the way: many thanks go to David Smith, Bob Koss and others for their precious work on hurricanes.

  307. Posted Oct 6, 2007 at 8:02 PM | Permalink

    The unvarnished truth about CO2 and tornadoes ( plot ).

  308. RomanM
    Posted Oct 7, 2007 at 6:54 AM | Permalink

    #306 Paolo

    You are obviously not aware that studies at the hurricane center have shown definitively that, due to AGW, the boundary of the tropics is moving northward at a rate of 0.194 degrees per year (19.4 degrees per century). ;)

  309. Kenneth Fritsch
    Posted Oct 7, 2007 at 7:31 AM | Permalink

    David Smith, have you heard about the dumb tornado viewer theory; the viewer, not warned of tornadoes by modern technology, was not able in the past times to seek safety and thus they tended to witness more tornadoes.

    I would like to graph tornadoes detected versus Cub fan disappointment but I found the correlation does not hold up by season, i.e. in the spring and early summer disappointment down and tornadoes up and in the late summer/autumn disappointment up and tornadoes down.

    Seriously, I would like to see you expand on Hollands’ theory of a changing area of tropical storm patterns versus the alternative of his observations being simply biased by historical changes in detection capabilities. The dumb ships theory in my mind sets the standard by which some of these climate scientists will rationalize their theories with little or no corroborating evidence and thus makes me tend to question all of their theories.

  310. Posted Oct 7, 2007 at 7:49 AM | Permalink

    RE #306, #308 The NHC even ran some of their tropical models on the swirl ( link ). The models appear confused by the disturbance.

    The SST beneath the swirl was around 18C. The generally-accepted minimum SST for tropical formation is 26C.

    It’s not clear to me why the NHC decided to mention this swirl.

  311. Posted Oct 7, 2007 at 8:00 AM | Permalink

    Re #309 Kenneth I like your DV theory. It’s got to be true, I can feel it in my bones :)

    OK, putting the goofiness aside, I’m looking at some of the regional details of the Smith-Reynolds SST reconstruction. This is the SST used in several papers. Some of the reported regional behavior in the tropics stretches the imagination.

  312. Posted Nov 19, 2007 at 6:33 PM | Permalink

    Matt V, you may be interested in a pending paper from James Elsner and (presumably) others regarding hurricane intensity and solar cycles. Elsner’s website is here . The relevant description is below:

    Sunday, November 11, 2007
    United States and Caribbean tropical cyclone activity related to the solar cycle
    The recent increase in the power of Atlantic tropical cyclones is attributable to greater oceanic warmth in part due to anthropogenic increases in radiative forcing from greenhouse gases. However solar activity can influence a hurricane’s power as well through changes in upper tropospheric temperature. Here we report on a finding that annual U.S hurricane counts are significantly related to solar activity. The relationship results from relatively more intense tropical cyclones over the Caribbean when sunspot numbers are low. The finding is in accord with the heat-engine theory of hurricanes that predicts a reduction in the maximum potential intensity with a warming in the layer above the hurricane. An active sun warms the lower stratosphere through ozone absorption of additional ultraviolet (UV) radiation. Since the dissipation of the hurricane’s energy occurs through ocean mixing and atmospheric transport, tropical cyclones can act to amplify a relatively small change in the sun’s output appreciably altering the climate. Results from this study have serious implications for life and property throughout the Caribbean, Mexico, and portions of the United States. The paper is currently under review for publication.

    We’ve looked at the Atlantic tropical cyclical behavior at CA ( see here ) but I (for one) was unable to correlate it strongly with solar activity as represented by sunspots. It’ll be interesting to see how that correlation is achieved.

    Elsner mentions the potential intensity hypothesis as a physical basis for the relationship. It may be more complicated than that, in my opinion, involving upper-tropospheric wind shear (related to TUTT behavior) and/or atmospheric stability.

    In any case it should be a nice read.

  313. David Smith
    Posted Nov 20, 2007 at 12:57 PM | Permalink

    Ryan Maue’s website opens with a comment about the Northern Indian Ocean (NIO) activity of 2007. The NIO activity, thanks to two powerful storms, is consderably above-normal in terms of ACE.

    The records, poor as they are, indicate that NIO storm count pre-1976 was higher than after 1976. Reliable intensity data is not available to the best of my knowledge. I wonder if ACE was higher in the NIO pre-1976 and the large climate regime shift of the mid-1970s resulted in a downward move. And, maybe we’re seeing a data point consistent with a return to greater NIO activity.

  314. Posted Nov 20, 2007 at 2:21 PM | Permalink

    David, consider also the opposite effect: tropical cyclones depleting stratospheric ozone through vigorous vertical motion. Solar activity is definitely a plausible argument — however, it would seem rather fortuitous for solar activity to affect short-time scales enough to overwhelm the likely long-period time scales of the ocean — aside from the obvious seasonal changes.

    annual U.S hurricane counts are significantly related to solar activity

    This is a pretty small subset…

    Many Bay of Bengal systems are remnant disturbances that progress westward over the Malay peninsula from the West Pacific. The climate shift may have some relevance when considering the genesis source of such systems.

  315. Posted Nov 20, 2007 at 8:00 PM | Permalink

    Re #313 Elsner’s pending paper looks for a correlation between solar activity and Atlantic hurricane activity. I plotted ( here ) the annual sunspot number, total Atlantic PDI and the August-October SST of the deep tropical Atlantic (“MDR”). This is not quite the same as Elsner’s work – he uses “US hurricane counts” and his solar proxy may be somewhat different – but should be interesting nonetheless.

    What I see is some kind of cyclic behavior in all three indices but I’m unable to get things correlated. Interesting, but a head-scratcher. I’ll take a look at US hurricane counts a little later, to see what that might offer, and at Ryan’s intriguing comments in #314.

  316. bender
    Posted Nov 20, 2007 at 9:01 PM | Permalink

    Really ought to get John Creighton’s filtering code running.

  317. Posted Nov 20, 2007 at 10:01 PM | Permalink

    Here’s another head-scratcher.

    This plot shows two time series: sunspot counts and those Atlantic tropical cyclones which came within 100km of land (North America, Central America, Caribbean Islands, The Bahamas and Bermuda). Cyclones which passed near or onto land over the last 140 years were likely detected, so this grouping of storms should be relatively complete.

    The plot shows apparent cyclical behavior in tropical cyclone count and, of course, in sunspots. My eyes think they see a hint of correlation but the series seem to come into and out of phase, so maybe my eyes are seeing an illusion.

    I’ll post a link to the (Excel) data tomorrow and offer conjecture on why the series might be related.

  318. Arnost Khun
    Posted Nov 20, 2007 at 10:10 PM | Permalink

    David

    As the state of the ENSO has an influence on Atlantic hurricanes – it may be interesting to see if this (and maybe the PDO cycle) in some ways effects the in and out of phase trend…

  319. bender
    Posted Nov 21, 2007 at 12:01 AM | Permalink

    David Smith, have you looked at Steve M’s use of wavelet decomposition in “benchamrking VZ pseudoproxies“? Since you’re looking for correlations between different processes operating at different time-scales, maybe that is the way to go?

  320. David Smith
    Posted Nov 21, 2007 at 7:46 AM | Permalink

    Re #319 bender I have not but will do so. A learning opportunity.

    Re #318 Arnost that’s a very interesting point. I’ll include some historical ENSO data see if we can detect something.

    Re #317 The plot from #317, blue line, shows that near-land Atlantic tropical cyclones underwent a sharp upturn circa 1930 and peaked within a decade or so of the upturn. It then began a 50-year slow decline. I wonder if we’ll see the same pattern with the circa 1995 upturn, showing a peak in the first decade of the 21’st century and then a slow decline. Perhaps that’s the nature of the AMO.

    Re #314 On my list of underappreciated phenomena is stratospheric ozone. Ozone affects stratospheric temperature and thus stratospheric circulation and thus tropospheric circulation and thus tropospheric climate. Perhaps a series of vigorous hurricane/typhoon seasons indeed affects the accumulation/depletion of ozone and thus triggers circulation changes that affect subsequent seasons. Solar activity plays a role in ozone of course and maybe sometimes the two (solar cycle and vigorous hurricane seasons) are in-phase and sometimes not. I plan to dig through some of the stratospheric reanalysis data and dust it for fingerprints.

  321. bender
    Posted Nov 21, 2007 at 9:27 AM | Permalink

    #320
    Maybe you will discover mid-frequency 5-10 yr cycles in stratospheric ozone that account for the observed 5-10 yr partial autocorrelations in hurricane frequency? It Is interesting to recall that there was a difference between the landfalling and non-falling hurricanne. I believe it was the non-landfalling hurricanes that indicated the 5y component. i.e. Something is happening over Atl ocean that is different than over NA continent.

    Of course those 5y and 10y componenets were very weak, so this is pretty dicey.

    Either way, you now have the basis for a potentially better hurricane forecasting model.

  322. bender
    Posted Nov 21, 2007 at 9:30 AM | Permalink

    Re #297
    It would not be hard to make an adjustment for observation/reporting bias over time. Your curve gives you the % slope that you would need to subtract from the raw data.

  323. Posted Nov 22, 2007 at 8:42 PM | Permalink

    I know we’ve beaten the Atlantic storm count question to a point beyond numbness but I want to show a couple of graphs. There is nothing new in these but they do help summarize a few points.

    First is the Atlantic tropical cyclone count, 1885-2007 .

    (This first graph excludes subtropical storms because they are not tropical cyclones and because they were ignored record-wise prior to 1970. Mann Emanuel Holland Webster and so forth include subtropical storms in their tropical cyclone counts which inflate the recent decades but to me their exclusion from a century-scale analysis is a no-brainer.)

    This first graph shows an irregular rise in the number of storms over the Twentieth Century. (The curve is often plotted alongside the reconstructed tropical sea surface temperature (SST) which gives a visual impression (in smoothed form) of a close Atlantic SST/count relationship.)

    But, people like me say wait a minute – storm detection methods have changed dramatically over the last 120 years. One cannot compare 1890 or 1910 or 1950 raw storm count with those of 1970 or 2000.

    Improved detection over the last 120 years has affected two categories of storms. One category includes those storms which are far at sea and which, pre-satellite or recon, were detected by chance encounters with ships.

    The second category includes storms which had very short existences. Short lives usually means the winds were quite weak and the aerial extent of those winds were small, making detection quite difficult. This second category occurs overwhelmingly near land, where detection is best and where the urge to err on the side of caution (and report higher wind values to the public) is high.

    The second graph shows these entirely-at-sea and short-lived cyclones .

    The red curve shows the emergence of short-lived storms in the record, consistent with growth in detection methods in the second half of the Twentieth Century. (Interestingly, these are almost all near-land storms and in the western half of the Atlantic basin, which fits no AGW hypothesis to my knowledge.)

    The blue curve shows those storms which never came close enough to land (including islands) to be reasonably assured of detection by landlubbers. Detection depended on ships and then recon flights and finally ever-improving satellites.

    Folks like me believe the upturn is mainly due to improved detection, especially as the 1970s generation of satellites were put into use and now phase-space analysis is put to use in analyzing cyclones outside the tropical Atlantic.

    Others believe the upturn is associated with warming SST in the eastern portions of the Atlantic. Plausible, but to that I’d say plot the blue line against eastern Atlantic SST and see how it relates.

    The third graph is of storms which came near land, excluding the short-lived ones .

    These are storms which existed long enough and were close enough to land to be reasonably detected, even in the Nineteenth Century. These account for the majority of Atlantic storms, almost 70%.

    The graph shows up and down motion consistent with a phenomenon called the Atlantic Multidecadal Oscillation (“AMO”) with a peak in the 1930s and another in the current decade. Importantly, it shows no long-term trend in storm count, despite the reported rise in tropical Atlantic SST.

    In summary, I believe the growth in reported Atlantic storm activity over the last 120 years is mainly, and perhaps entirely, due to improved detection.

  324. Posted Nov 22, 2007 at 9:34 PM | Permalink

    Re #323 Here , by the way, is the graph of sea surface temperature in the “Main Development Region” (tropical eastern Atlantic) and the stayed-at-sea (mostly eastern and middle Atlantic) tropical cyclones. If someone can explain how the SST behavior drove the increase in storms during the 20’th Century, please post.

  325. Posted Nov 24, 2007 at 1:43 PM | Permalink

    Here are a few more notes on Atlantic storm count, specifically short-duration storms. This is mainly a wrapup before I file away the charts and maps.

    First, here is the time series of short-duration storms (24 hrs or less at storm strength), updated and with footnotes added.

    I divided the series at 1965, as 1964-65 marked the start of the Nimbus satellite system. For 1885-1965 the short-lived storms accounted for less than 1% of all storms. However, for 1966-2007 the short-lived storms accounted for 9% of all storms, a material increase.

    Second is a map of where these short-lived storms occurred (their point of origin) in the eighty years of 1885-1965 ( link ). There are very few storms with all but one occurring along the Gulf Coast.

    Third is a map of short-lived storms in the forty-odd years of 1966-2007 ( link ). Note the cluster in the sensor-rich upper Gulf region (and, interestingly, in the extreme southwest Gulf where nearby terrain may play a role in increasing the cyclone winds). The open-Atlantic systems often were marginally warm-core systems which were judged to have been tropical for a short period, based mainly on satellite evidence.

    A more-thorough way of examining the question is to go back through the individual short-lived storm records and see whether there was any evidence of storm-forced winds by ship and shore observations. If there is then there is a basis for including that storm in a century-scale analysis. If not, then it should be culled. That would be a major undertaking, maybe for another time (or perhaps as a student project), but not today.

  326. Posted Nov 24, 2007 at 2:40 PM | Permalink

    Re #325 Here are the charts re-centered to 1945 (start of aircraft recon):

    Time Series

    Pre-1945 Ship and shore observations only

    1946-2007 Recon era plus satellites, radar, GPS dropsondes, buoys, etc

  327. Kenneth Fritsch
    Posted Nov 24, 2007 at 3:59 PM | Permalink

    Re: #s 325 and 326

    David Smith, that was once again a revealing analysis and well done.

    I would like to look at the Thomas A. Sabbatelli and Michael E. Mann article
    “The influence of climate state variables on Atlantic Tropical Cyclone occurrence rates” published in the JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 112, D17114, doi:10.1029/2007JD008385, 2007 linked here:

    http://www.meteo.psu.edu/~mann/Mann/articles/articles.html

    The authors here analyzed NATL TC counts assuming a Poisson distribution that is affected by state variables which in this case they selected Main Development Region (MDR) SST and ENSO (Nino3.4). Their analyses were by two methods. The first was to use binary and tertiary classifications to extract from the time period 1870-2004, the years that were favorable for TC occurrence for the 2 variables, unfavorable for the 2 variables and neutral for the 2 variables. Chi square testing was then performed on these categorized years (with obviously differing Poisson means for each of these categories) for goodness of fit to a standard Poisson distribution with the calculated mean.

    They obtained reasonably good fits to Poisson distributions by this categorization which was in contrast to fitting the whole time period with a standard Poisson distribution, using the entire time period, yielded a p = less than 0.05 in the goodness of fit test. By the way, I agree that using the entire time period does not give a good fit to a standard Poisson distribution – a finding with which some posting here disagreed. What I had found was that using Willis E.’s detrended distribution with the cyclical component removed fit a Poisson distribution very well for the longer time periods. I see most of that trend being due to improvements in detection of TCs, whereas Mann sees it as increasing SSTs. Unfortunately the effects can be easily confounded. His analysis admits to a reoccurring cyclical component. Mann and Sabbatelli use the dumb ships theory to completely ignore for this analysis that the detection capability for TCs changes over this very long time period – although they talk about improving their model by including changing detection capabilities as a variable.

    The authors’ second method of analysis used a generalized linear model for the expected occurrence rate using a Poisson distribution and the state variables of SST, and ENSO and NAO indexes and then estimated maximum likelihood values for the beta coefficients in the model. They tested the models using R^2 and MSE.

    If you get a chance to read this paper I would like to discuss it with you or any other interested posters. Also please note the time periods (months of year) that the authors use for MDR SST, ENSO and NAO indexes and the region that is selected for the MDR SST. Let me know if you judge that other months and locations could have been selected for these variables, so that I could attempt a sensitivity study.

  328. Posted Nov 24, 2007 at 4:59 PM | Permalink

    Re 324:

    Could you please present the same graphs using SSTs which do not include the Folland and Parker adjustment?

    JF

  329. Posted Nov 24, 2007 at 5:56 PM | Permalink

    Re #327 Hello, Kenneth. I scanned the paper several weeks ago, to get the gist of their method, but didn’t read it closely. I’ll do so soon. My take was that their approach looked reasonable but their data choices were problematic.

    I’d like to first offer my conjecture on the physical basis of the issue.

    ** ENSO influences tropical cyclones globally, including the Atlantic. This is rather well-established.(Incidentially, I think that Bill Gray was the first to recognize the Atlantic role decades ago.)

    ** SST variability is a trickier issue. It can be both a physical contributor to tropical cyclone activity and/or it can be an indicator, a symptom of other important phenomena, such as atmospheric pressure and wind patterns.

    This plot shows SST cycles but there is also a clear pattern of sea-level pressure (Western Caribbean) cycling. That pressure cycling appears related to upper-atmospheric wind patterns and perhaps stability (I can send a copy of Knaff’s paper on that to you if you want). Perhaps the key variables for Atlantic cyclones are these atmospheric patterns and not SST, with these same atmospheric patterns (or what causes these patterns) also causing the short-term SST variability. Complex.

    Regarding their choice of data:

    ** I think the use of August-October SST is reasonable.

    ** They use SST in the MDR, which looks OK for their purposes. However, it would have been interesting (to me) if they had also plugged in an Atlantic dipole (MDR SST minus the SST in a certain part of the South Atlantic). This dipole is an indicator of AMO activity. This would give some indication of whether the role of MDR SST is absolute or whether its behavior is simply an indicator of the phase of the Atlantic Multidecadal Oscillation.

    ** Regarding storm count, I would have used the subset of “near-land, excluding short-lived”, which is this plot . I would also have started at 1885, because that is as far back as the Caribbean data was reconstructed (I forget the name of the man who did that work but it’s in the Monthly Weather Review archives). This subset covers 70% of all Atlantic storms and avoids (in my opinion) much of the missing-storm problem. For fun, I’d do a separate run using never-reached-land subset (the blue line), which covers 30% of all storms.

    Kenneth I can provide the storm count data in Excel form if you wish and I can generate the SST dipole data. Just let me know if you want them.

  330. Posted Nov 24, 2007 at 11:28 PM | Permalink

    RE #328 Hello, Julian. The SST data source is the Smith-Reynolds Extended Reconstruction as provided by the server here . It’s not clear to me whether the version provided by the server is is #2 or #3. I’ll be glad to post the graphs without the Folland/Parker adjustment if you’ll point me towards a data source.

    Is the issue as described below?

    Before 1942 most SST measurements were from
    ships that used buckets to bring samples of seawater
    onto the deck, where temperature measurements were
    made. Afterward it became more common to measure
    the temperature of the engine-intake seawater. Adjustments
    to the pre-1942 SSTs were developed by Folland
    and Parker (1995), and by Smith and Reynolds (2002).
    However, further analysis of the ICOADS release 2
    SST by C. K. Folland (2003, personal communication)
    indicates that for 1939–41, the release 2 data are biased
    warm relative to the data used by Folland and Parker
    (1995). The release 2 data contain additional data, from
    different sources and with different bias characteristics
    compared to the Folland and Parker (1995) SST data.
    Those differences are minimized if the bias correction is
    reduced linearly to zero beginning in January 1939 (no
    adjustment to the bias correction) and ending in December
    1941 (zero bias correction). Because we use the
    release 2 data, we apply this linear reduction to the
    Smith and Reynolds (2002) bias adjustment from 1939 to 1941.

    (from Smith Reynolds 2005)

  331. Bob Koss
    Posted Nov 25, 2007 at 3:26 AM | Permalink

    David,

    Tried your SST link. Evidently something wrong with it. I get a not found on server error.

    About a month ago I was able to get the Reynolds v3 data from here. GZ compressed ascii or netcdf versions are available. There are also standard deviation files (esd) in the same directory. Mistakenly I first downloaded those thinking they were the temperature files. The link is still good. Seems like they updated the latest file since I got them. Probably added October data.

  332. Posted Nov 25, 2007 at 5:59 AM | Permalink

    RE 330: there’s a good thread on CA about the Folland and Parker adjustment. Because of my own particular interests I always look for an early rise in temps just before WWII. I know if you knock off the F&P you get a steep rise in 39/40, add it in and the rise starts earlier than I want to see – besides, I have read (but don’t know how correct the assertion is) that the correction was sought in order to make a model work. Not a good motive and open to misinterpretation. My opinion is all eyeball from other people’s graphs.

    BTW, I should have phrased my first request better: ‘Is there any chance’ might have been a more felicitous choice of words. Sorry about that.

    Some idea of the validity of the bucket correction may be found by looking at the Hadcrut3 NH temperature anomaly and comparing it with the records for Valentia (51.9N 10.2 W), an observation point which might be expected to share the characteristics of the near body of water.

    JF

  333. Posted Nov 25, 2007 at 8:45 AM | Permalink

    Bob, here’s the link . Smith-Reynolds access is about midway down the page. I could not find a clear reference to whether it is v2 or v3, perhaps I missed the note.

    Julian the SST reconstruction seems full of assumptions and best-guesses, which is rough on any attempt to look for fractions of degree C changes in remote regions decades ago.

    A while back I compared Smith-Reynolds SST anomaly to that provided by NCEP, which as best I could tell was a Hadley version. This was for the Western Atlantic. The resulting plot is here . (“HW” is the Smith-Reynolds reconstruction.)

    What caught my eye was what looked almost like step changes in the comparison, with the steps smoothed so that the changes weren’t too blunt. It looked to me like one of the versions had some kind of adjustments applied, at least in the region examined.

    Maybe they were grafting reconstructions.

    If there’s an alternate explanation, involving differences over time in unprocessed data, I like to learn about it.

  334. Posted Nov 25, 2007 at 5:13 PM | Permalink

    Here is an interesting graph.

    It shows two parameters: the “Atlantic dipole” (from the teleconnection collection) and the Atlantic “ACE”.

    The Atlantic dipole is an indicator of thermohaline activity (see Latif et al 2006). It measures the contrast between sea surface temperatures in the North Atlantic (40 to 60N) and the South Atlantic (40 to 60S). The greater the contrast, the greater the thermohaline (MOC) activity.

    The Atlantic ACE is a measure of Atlantic tropical cyclone activity and is a function of storm count, duration and intensity. The more active the hurricane season, the higher the ACE.

    The chart shows evidence of a relationship between the two. The dipole declines circa 1970, which was also the end of the last active hurricane era. From 1970 into the 1990s both the dipole and ACE were low, with the exception of those odd decadal-scale upturns in 1980 and 1990. Then in the mid 1990s both the dipole and ACE take a sharp turn upwards.

    The ACE data I had extended back only to 1950 and the dipole forward only to 2004. I’ll extend the dipole data forward but the historic (pre-1950) ACE values may not have a lot of value due to lack of direct measurements of storms.

    The physical basis for the connection is open to conjecture. Seems like Bill Gray was the one suggesting a THC/hurricane connection, though the physical mechanism or evidence was never clear to me.

    Kenneth, this is an indication that dipole behavior may have been a good one for Sabbatelli to have used, along with the tropical cyclone subset mentioned in #329.

  335. Posted Nov 25, 2007 at 8:47 PM | Permalink

    Re #334 I’ve adjusted the graph (extended the ACE back to 1947 and the dipole forward to 2006; estimated both values for 2007; recentered the ACE curve slightly)

    Link

  336. Posted Nov 26, 2007 at 9:18 PM | Permalink

    As mentioned, I believe that Atlantic storm activity is best shown by a plot of storms which were detectable from land and which excludes the modern practice of naming short-lived (weak and small) storms. Such a plot is here . There is no long-term increase, only the cyclic activity of the AMO.

    One thing I find interesting is the similarity between some of the detail of the last two cycles. Admittedly this may be simple conicidence but it’s interesting anyway. The explanations are given on the graph.

  337. Steve McIntyre
    Posted Nov 26, 2007 at 10:44 PM | Permalink

    David, can you post up/email an ASCII file with your list of storms denoting which ones you’ve classified as “Small” and “Far from land” together with the operational definition.

  338. Posted Nov 27, 2007 at 5:38 AM | Permalink

    Yes, will do.

  339. SteveSadlov
    Posted Nov 27, 2007 at 10:34 AM | Permalink

    In addition to improved detection there is also a human foible element in play. Storms that are not really TCs at all have increasingly been counted. This has been an increasing problem since the mid to late 1990s. In the ancient past, TC professionals would take a more conservative approach, insisting that multiple criteria (actual recorded wind, cloud / wind pattern, core temperature, cloud top temp, seed origin, etc) were met, prior to naming and claiming. But now, even occluded fronts, nor easters that float over the Gulf Stream, cut off lows that started over Nevada and drifted down over Mexico then off of Belize, and other mid latitude feature that conveniently collided with minor tropical waves, have been increasingly named and claimed. Count padding and book cooking. I call ‘em like I see ‘em.

  340. T J Olson
    Posted Nov 27, 2007 at 10:52 AM | Permalink

    Today, Bill Gray’s Tropical Meteorology Project at Colorado State University has posted their hurricane season ending results.

    This pull-quote is irresistable: “Meteorologists are known to be absolutely brilliant at after-the-fact explanation of weather phenomena … but please don’t press us too hard on future events!!”

    They predicted 9 hurricanes, but only 6 materialized.

  341. Posted Nov 27, 2007 at 8:57 PM | Permalink

    Steve M, per your questions on short-duration storms:

    * my definition of “short-duration storm” is 24 hours (or less) at a windspeed of at least 35 knots. Since the hurricane database shows 6-hr periods, this definition corresponds to no more than 4 six-hour periods at a windspeed of at least 35 knots. Yours may have captured some with 5 periods, which I consider to be a 30-hr storm, which is outside my definition.

    * “short-duration storms” do not include subtropical storms

    * my maps show the initial point where a storm achieved 35 knot winds, which is where storm-force winds could first be detected. On the other hand, using midpoints of a total track will give odd results because it would include the very weak depression stages of a storm. Perhaps the best track midpoint is the midpoint of a storm’s path while it has 35 knot (or higher) winds.

  342. Posted Nov 27, 2007 at 9:55 PM | Permalink

    A file containing annual tropical cyclone data, plus some SST and other data, is located here .

    I expect to have the individual storm data file completed this weekend.

  343. Kenneth Fritsch
    Posted Nov 27, 2007 at 10:08 PM | Permalink

    Re: #329

    ** Regarding storm count, I would have used the subset of “near-land, excluding short-lived”, which is this plot . I would also have started at 1885, because that is as far back as the Caribbean data was reconstructed (I forget the name of the man who did that work but it’s in the Monthly Weather Review archives). This subset covers 70% of all Atlantic storms and avoids (in my opinion) much of the missing-storm problem. For fun, I’d do a separate run using never-reached-land subset (the blue line), which covers 30% of all storms.

    David Smith, I will take you up on the offer of emailing your Excel spreadsheets on the TC counts that you noted in this excerpt. I believe you have my email address, but I can send it to you if you have misplaced it. Thanks.

  344. Steve McIntyre
    Posted Nov 27, 2007 at 10:41 PM | Permalink

    #342. I realize that you’re working on things. For me to be able to use your classification, I bneed a table showing the “near-land” classification for each storm and an operational description of how the allocation was done. Annual is interesting but insufficient detail for me. Thx

  345. Posted Nov 28, 2007 at 5:49 AM | Permalink

    Re #343, #344 No problem at all! This is simply a week full of loose ends to wrap up before heading to Florida to watch a shuttle launch (friend headed into space). It’s also time to wrap up the 2007 contest, as the season officially ends Saturday.

  346. Kenneth Fritsch
    Posted Nov 28, 2007 at 4:24 PM | Permalink

    David Smith, I found your Excel SS info that I required on total tropical cyclones (Total) for 1860-2007 and for those tropical cyclones that excluded short lived and “at sea” storms (Easy Detection) for the same time period. All storm data are for the NATL.

    I looked at the period 1885-2007, as you suggested, and the entire 1860-2007 period. I looked first to determine whether the Easy Detection storms would fit a Poisson distribution (using a chi square goodness of fit test) for the period 1885-2007. Both the Total and Easy Detection storm categories gave a p less than 0.03 for this time period and thus one could reject the null hypothesis that the actual distribution fit a Poisson distribution with the calculated means. I then calculated trends for the two categories and found that the Easy Detection category storms showed little of no trend while the Total storms had a relatively large trend.

    I believe when one uses the more readily detectable storms (Easy Detection), the increasing trends in storm counts that Mann and others attribute to increasing SSTs are diminished to near zero. Since the tropical storm count series (the category Total storms) when detrended and with the cyclical component removed by Willis E showed an excellent fit to a Poisson distribution, I would conjecture that the Easy Detection category storms would need to have the cyclical component removed to better fit a Poisson distribution.

    The trends and means, calculated as described above, are listed here:

    Easy Detection Storms:

    Mean 1860-2007 = 6.0 storms per year.
    Trend 1860-2007 = 0.46 storms per 100 years.

    Mean 1885-2007 = 6.2 storms per year.
    Trend 1885-2007 = -0.56 storms per 100 years.

    Total Storms:

    Mean 1860-2007 = 8.8 storms per year.
    Trend 1860-2007 = 3.66 storms per 100 years.

    Mean 1885-2007 = 9.2 storms per year.
    Trend 1885-2007 = 3.22 storms per 100 years.

  347. reid simpson
    Posted Nov 29, 2007 at 5:00 AM | Permalink

    “Decisions to name storms draw concern

    With another hurricane season set to end this Friday, a controversy is brewing over decisions of the National Hurricane Center to designate several borderline systems as tropical storms.

    Some meteorologists, including former hurricane center director Neil Frank, say as many as six of this year’s 14 named tropical systems might have failed in earlier decades to earn “named storm” status.”

    http://www.chron.com/disp/story.mpl/front/5337583.html

  348. David Smith
    Posted Nov 29, 2007 at 9:01 AM | Permalink

    Re #347 Well-written news story by Eric Berger that captures some of the issues at play in storm count. I’m not so sure about Judith’s comment, as I believe that olden-day forecasters looked for corroberating evidence (a time-match of strongest wind and lowest pressure, for instance) which would tend to rule out non-tropical systems.

  349. SteveSadlov
    Posted Nov 29, 2007 at 11:34 AM | Permalink

    RE: #347 – I am not alone in my ongoing strong (and to to some, I reckon, annoying) critique.

  350. bender
    Posted Nov 29, 2007 at 11:52 AM | Permalink

    Not annoying, Sadlov. These issues of systematic temporal bias are important enough that Mann publishes on them. Now he must estimate THIS effect and try to remove IT from the analysis.

    Which he will, because he appears to get all his ideas & direction from CA.

  351. SteveSadlov
    Posted Nov 29, 2007 at 12:02 PM | Permalink

    RE: #348 – Once again, the wiley Dr. Curry shows an ever so slight peek of her cards. (e.g. Warmism)

  352. tpguydk
    Posted Nov 29, 2007 at 12:03 PM | Permalink

    #349, I have to admit that I did find your critque a little annoying, but it made me think, and I believe that you are right. I don’t believe in conspiracies but something indeed is up if almost half the storms (I’ll grant Andrea and Barry that never should have been named right off the bat, no subtropical storm should) shouldn’t have been named.

    Thanks for making me think.

  353. MarkW
    Posted Nov 29, 2007 at 12:08 PM | Permalink

    #341: You state that storm data shows wind strength in 6-hr windows. Does this mean that wind speed was at or above 35 knots for the entirety of the 6 hr window, or just that it reached that level at least once during that window. If the later, then a storm that registers for 4 of these windows, could have been a storm for as little as just over 12 hours.

  354. Bob Koss
    Posted Nov 29, 2007 at 12:26 PM | Permalink

    MarkW,

    The NHC uses one minute sustained wind for their area of coverage the Atlantic and Eastern Pacific basins. With some of the newly automated stations returning two minute sustained winds. Some of the other storm watching organisations in the other basins use ten minute sustained wind.
    So there is a certain amount of fudge-factor with the reporting. Those winds are for a height of ten meters in an unobstructed area.

  355. Posted Nov 29, 2007 at 12:41 PM | Permalink

    In fact, there are reasons to believe that historical storms have been overcounted as well as undercounted, said Judith Curry, chair of the School of Earth and Atmospheric Sciences at the Georgia Institute of Technology.

    Before satellites, scientists had few ways to tell the difference between tropical systems and non-tropical storms. As a result, some non-tropical storms probably were named.

    http://www.chron.com/disp/story.mpl/front/5337583.html

    am i the only one to see a pattern in this type of analysis?

    finding lots of problems with modern measurement while accepting the (sometimes quite far) past as 100% accurate?

    (data and graphs though are nice and pretty impressive)

  356. bender
    Posted Nov 29, 2007 at 1:40 PM | Permalink

    “An oncologist today would use the latest technology for determining and assessing one’s cancer,” Read said. “Would you use a doctor who only used X-rays instead of the latest MRI?”

    For chrissakes, no one’s complaining about the better technology! It’s terrific! The problem is the trend in the data – as incredibly weak as it is – is inflated by the better technology, the number of observers at sea, the increased tendency to give names to weaker storms. All these biases favor a positive trend in hurricane counts, even if hurricane occurrence is flat.

    Have people stopped thinking? Are we there yet?

  357. Kenneth Fritsch
    Posted Nov 29, 2007 at 2:46 PM | Permalink

    Re: #355

    Sod, I think your Judith Curry excerpt clearly shows what I think affects a number of these climate science conversations.

    A number of participants at CA have done detailed and extended analyses of what I like to call Easy Detection (using various categorizations) storm counts or, at least, More Easily Detected storm counts and then compared the trends of Easy Detection to Total storm counts over the past 120+ years. The Easy Detection counts give trends that are practically flat while the unadjusted Total counts show significant increases in counts over the length of these long time periods. The prominent climate scientists, on the other hand, like Curry, Mann, Emanuel, Holland and Webster apparently can arm wave their way through these analysis by speculating that ships in the past were dumb (Dumb Ship’s Theory) and observed Tropical storms because modern detection equipment did not warned them away and thus they detected all the storms with little opportunity to miss them.

    Curry’s speculation that the lack of modern detection capabilities could have resulted in over, as well as, under counting in pre-modern times appears to be backed by no more evidence than that of the Dumb Ship’s Theory. Yet I am sure that Curry’s speculation could well be included in a peer-reviewed paper and than referenced in many other peer-reviewed papers just as has occurred with the Dumb Ship’s Theory.

  358. steve mosher
    Posted Nov 29, 2007 at 2:54 PM | Permalink

    If ships dont undercount by more than 1.2, then the solution is simple.

    Going forward all TS will be deteriemined by “ship count” + 1.2.

    No storm shall be named on the basis of satillite recon, plans, long range radar.

    Ship count + 1.2.

    problem solved.

    ALWAYS call the bluff with the puffery they spew.

  359. Kenneth Fritsch
    Posted Nov 29, 2007 at 3:16 PM | Permalink

    Re: #358

    Steven Mosher, in past times ships were dumb, and they saw. In current times ships are smart, and they hide (Dumb Ships Theory). Therefore, you cannot use smart ships + 1.2 for counts going forward.

    A better resolution would be to ask for evidence for these speculative theories that lead to minimal historical undercounting– and in context of the trends for Easy Detection counts versus trends for Total unadjusted counts and the obvious vast improvements in detection capablities over these time periods.

  360. Posted Nov 29, 2007 at 3:47 PM | Permalink

    A number of participants at CA have done detailed and extended analyses of what I like to call Easy Detection (using various categorizations) storm counts or, at least, More Easily Detected storm counts and then compared the trends of Easy Detection to Total storm counts over the past 120+ years. The Easy Detection counts give trends that are practically flat while the unadjusted Total counts show significant increases in counts over the length of these long time periods. The prominent climate scientists, on the other hand, like Curry, Mann, Emanuel, Holland and Webster apparently can arm wave their way through these analysis by speculating that ships in the past were dumb (Dumb Ship’s Theory) and observed Tropical storms because modern detection equipment did not warned them away and thus they detected all the storms with little opportunity to miss them.

    so you completely rule out that modern equipment might keep us from falsely reporting a storm as hurricane that wasn t one?

    and you firmly believe that ships will accurately count storms? never overdo it? and they undercount the length of the biggest fish they ever caught as well?

  361. bender
    Posted Nov 29, 2007 at 4:09 PM | Permalink

    David Dmith,
    You may be interested in this article, linked to by Dev:
    North American drought: Reconstructions, causes, and consequences

    Note thie link between La Nina, zonal flow patterns & US drought. Of course anyone in the southeast knows about the relationship betweeen lack of hurricanes and drought …

    All these threads are starting to weave themselves together.

  362. steve mosher
    Posted Nov 29, 2007 at 4:45 PM | Permalink

    RE 359. Jeez oh pete. I need to hire some of these guys into my marketing
    departments, they have been prelobotimized.

  363. steve mosher
    Posted Nov 29, 2007 at 4:46 PM | Permalink

    re 360. Pass me the Roundup!

  364. Kenneth Fritsch
    Posted Nov 29, 2007 at 5:15 PM | Permalink

    Re: #360

    so you completely rule out that modern equipment might keep us from falsely reporting a storm as hurricane that wasn t one?

    and you firmly believe that ships will accurately count storms? never overdo it? and they undercount the length of the biggest fish they ever caught as well?

    Please use your reasoning to explain how the trend of the annual Easy Detection storm counts have not appreciably changed over the past 120+ years.

    Modern detection gives a much more accurate account of storms and we are much more sensitive to storm counts now than we were in past times.

    In past times it was a matter of actually seeing a storm in order to record it as one. The fish fibbing about storms had less relevance in times past. The theories of Emanuel, Curry, Webster, Holland and Mann made no matter in those times.

  365. D. Patterson
    Posted Nov 29, 2007 at 9:34 PM | Permalink

    364 Kenneth Fritsch says:
    November 29th, 2007 at 5:15 pm
    Re: #360

    The use of a Dumb Ships hypothesis is inexcusable when there are millions of meteorological marine ship reports giving position and weather conditions going back as far as the 15th Century. All an investigator needs to do is plot the successive positions of the ship reported in the ship’s log to see if it is using Buy Ballot’s Law and its preceding customs among mariners to see if the ship is evading an approaching tropical storm or hurricane. There is no need for wild and unsupportable speculation when there is such a mammoth treasure trove of direct and empirical evidence.

  366. tetris
    Posted Nov 29, 2007 at 10:11 PM | Permalink

    Re: 364
    Kenneth Fritsch
    Maybe I’ve been missing something.
    Based on all available data for the 2007 season, with the best “modern detection” that “gives a much more accurate account of storms” we now have an official NA TS record that by generally accepted criteria contains a minimum of 2 [and probably 3] bogus storms. More importantly, as Ryan Maue has pointed out, the key ACE metric goes back to the 1977 low.
    Are we to believe Drs Emanuel, Holland, Curry, Webster and Maestro Mann and their various theories or simply accept the data before us. Why not a run-off between the theories and reading fish guts?

  367. bender
    Posted Nov 29, 2007 at 10:31 PM | Permalink

    Are we to believe Drs Emanuel, Holland, Curry, Webster and Maestro Mann and their various theories or simply accept the data before us.

    But their theories are not incompatible with the data. In their models, they predict a tiny increasing trend of debatable magnitude that is dwarfed by oscillations and noise … and that is what we see. Their further argument is that a lot of the oscillation is AGW working through some heat dissipation circulatory pathways, such as ENSO. These arguments at CA about biases leading to a spurious increasing trend – correct as they may be – need to be put in context: most of tha variation in hurricane occurrence is medium and high frequency variation. The trend is miniscule.

    Where these authors are going wrong – and this is just my opinion – is with their press releases and public statements, which seem to play up the magnitude of the trend and the strength of evidence supporting the attribution of the cyclic component to AGW. That is the line between science and alarmism.

    It’s not a matter of “belief” in someone. It’s a matter of taking a cold look at what their models say, and judging the models based on their structural soundness and predictive power.

  368. Kenneth Fritsch
    Posted Nov 30, 2007 at 11:54 AM | Permalink

    It is too bad we have three threads covering the same general subject matter. The link listed below, from another of the three threads, to a David Smith post and analysis (and particularly the question about the appearance of cycles in the easy to detect storms time series with little trend as contrasted with a lack of cycles and a large trend in the difficult to detect storm time series) is most relevant to the discussion on this thread about the effects on storm counts from improving detection capabilities.

    http://www.climateaudit.org/?p=2114#comment-169269

    I am rather satisfied that all these analyses of easy to detect storms show evidence for a significant under count in storms from historical times. Producing speculative theories without evidence, such as the Dumb Ship’s and Past Counts Are Equally Over and Under, speaks more to how things are done in this area of climate science than it does about handling the data.

    Landsea has apparently directly addressed some of the undercounting issues. On the other hand, it is my view that the proponents of a strong connection between tropical storm counts/intensities and rising SST seemed to want to look at the NATL in isolation, ignore the Kossin re-analysis results for the other storm development areas around the globe and speculate on why they can use the NATL long time series of TS counts with little or no adjustments for improving detection capabilities.

  369. Posted Nov 30, 2007 at 12:19 PM | Permalink

    Re #368 Kenneth I’ve got some intersting (to me) comments on another grouping of storms which I’ll post soon. I’m thinking of calling them the “Tiny Tim” storms, after Dickens’ novel.

  370. David Smith
    Posted Nov 30, 2007 at 1:48 PM | Permalink

    Re #353 Mark that’s a good question and it touches on an important issue. The stated windspeed is an educated guess and assumes that the wind remained at that speed during the entire six hours. That, of course, may or may not be true, but the forecasters stick to that estimate unless they have new data to warrant a revision.

    The important issue is this – tropical storms and many hurricanes are not sharply-defined phenomena. This is a point that often gets missed. When a forecaster reports a windspeed he or she uses instruments (which have error) which may or may not be finding the strongest part of the storm, all while the storm fluctuates. Additionally, the forecasters are talking to the public, so there is a need for short-term consistency in what they say and a need to avoid reporting the wiggles and surges and ebbs and conflicting data that are quite common.

    Young, weak tropical cyclones are especially small and asymmetrical and often are little more than loosely-organized thunderstorms. Even the task of finding the center requires guesswork. The bottom line is that there is a large amount of educated guesswork in measuring these things.

  371. Posted Nov 30, 2007 at 6:22 PM | Permalink

    Part 1:

    Tiny Tim is a Charles Dickens character. Tiny was a young lad, small, very weak, in a struggle to survive and of little notice in the hustle-bustle streets of London. Later, of course, his fortunes improved and he and Scrooge became “part of the record” of Victorian England.

    In a similar vein (OK, it’s a stretch) there is a type of Atlantic tropical cyclone that is like Tiny Tim: generally of short duration, weak winds, small aerial extent and often in a remote part of the ocean. Its impact on its environment is tiny (a very small “footprint” in the Atlantic).

    My operational definition of “Tiny Tim storms” are those that were so minimal that the NHC end-of-season reports do not report a single ship or single shore report of storm-force winds. This is not a matter of report oversights – storm analysts consider surface verification of wind estimates to be an important matter and list shore weather reports and ship reports in their reports.

    And, the lack of ship or shore reports is quite significant if someone is looking at storm climatology. Storms lacking ship or shore reports of storm-force winds would, prior to 1945 (the start of recon), not have been classified as a tropical storm/hurricane. Why? Because, prior to 1945, all the meteorologists had were ship and shore reports. No aircraft recon, no satellites, no buoys and no Doppler radar – just ship and shore reports.

    So, in this era of strong and many ships, rapid reporting and (US) shores lined with windspeed devices like onshore CMAN stations, a seeming plethora of data, are there still Tiny Tim storms, ones that modern technology sees but which lack storm-strength impact on ships and shores and which would have been ignored in the past?

    The answer is in Part 2 (I’m doing this post in several parts rather than one overly-long one).

  372. Posted Nov 30, 2007 at 7:38 PM | Permalink

    Part 2:

    The US National Hurricane Center (NHC) makes its end-of-season archives available at its website . An example of a storm report is here, the infamous Hurricane Katrina which shows a wealth of information including about 70 selected ship observations (hmmm, must have been some old dumb ships out there left over from the 1930s) of storm-forced winds and about 50 selected onshore observations.

    Another example is Tropical Storm Ernesto , a report with with much less content because, well, it wasn’t much. There were no ship reports of storm-force winds and, as the NHC acknowledges, even in reanalysis it is of questionable strength or organization. Yet it carries as much weight in storm count trends as does Katrina.

    (A word about reviewing the NHC archives – the ones for recent years are well-written and organized but that quality (for climatological purposes) diminishes as one goes back in time. There is a lot of verbage and data to review. I say this because I reviewed about 250 reports for this post and I may have missed some detail, one way or the other. I doubt that it’s material but I want to mention it anyway and welcome anyone who might audit my list.)

    I reviewed the last 20 years of records as I figured that covered the modern increased-activity era (and the 1980s record quality became a bit more challenging).

    So, the question of the hour is: how many Tiny-Tim storms, ones with nary a ship or shore report of storm winds, occurred in the last 20 years? The answer is here .

    Frankly I was surprised. There are 52 storms on the list.That’s 52 out of the 252 storms in the official record, or 20% of the total. That’s 20% of the modern storms which lack a single classical (ship or shore) report of storm winds. Wow.

    The obvious question is: how can one compare these satellite- and aircraft-based storms, which left no ship or shore evidence, with pre-1945 records which were based solely on ship and shore observations?

    Next: a little data

  373. Posted Nov 30, 2007 at 8:41 PM | Permalink

    Part 3:

    First, here’s a look at a couple of characteristics of the Tiny-Tim group. Here is a bar plot of the duration of the Tiny Tims, grouped by days of existence (6 to 24 hours = 0 to 1 day, 30 to 48 hours = 1 to 2 days, and so forth).

    The median duration is 1.7 days (42 hours). A few storms lasted beyond four days, ones that tended to be in remote open waters. For perspective, something that moves at, say, 10mph and lasts 2 days doesn’t cover a huge amount of real estate.

    How about winds? Here’s a bar plot of windspeed distribution for the Tims. It shows that the group combined had 182 six-hour periods (45.5 days) of winds in the 35 to 39 knot range, as estimated by aircraft, satellite or buoy. The distribution has a mean windspeed of 43 knots (“strong gale” on the Beaufort scale) with 85% of the time spent below 50 knots.

    There is an important graphic which I wish I could present but cannot because, to my knowledge, the data does not exist. The graphic would convey information on the geographical extent of storm-force winds. This is important because Tims likely have peak winds in only a small area on the eastern side of the center, perhaps 30 to 50 miles across typically. Tropical storms often lack symmetry and have their strongest winds in a relatively small area of thunderstorms.

    As an exercise for perspective, figure that the hurricane-prone portion of the Atlantic covers 8 million square miles and that a Tiny-Tim has storm-force winds 100 miles across and moves at 10 mph for 2 days before weakening. That equates to the Tim covering 0.6% of the tropical Atlantic, which is not much.

    Another useful graphic, which I have not done, would be a map of the storm locations. I think we’d see Tiny-Tims in the Gulf, along the eastern US seaboard (frontal-zone Tims), in the remote open Atlantic and scattered elsewhere.

    OK, that’s a view of the group. Now for the main question: how have these storms affected the all-important trend in Atlantic storm count? That’s part 4.

  374. SteveSadlov
    Posted Nov 30, 2007 at 8:54 PM | Permalink

    RE: #373 – Occluded front Tims, Tonopah Low collided with weak tropical wave Tims, clockwise rotating diffuse blob of severe Gulf “monsoon” thunderstorms Tims, Nor’easter Tims, squall line from the mountains of Haiti which ended up barely rotating with heavy cells causing flash floods washing away cardboard shacks Tims ….

  375. Posted Nov 30, 2007 at 9:41 PM | Permalink

    Part 4:

    What does the long-term time series of Atlantic tropical cyclones look like if the recent Tims are omitted?

    Since my data covers only the most recent 20 years the plot is rather odd but does offer some information. The blue line is the official record (Tims included) while the red line is what the 5-year average would look like without the recent Tims. The comparisons should be (1) between the red and blue lines for 1988-2007 and (2) the red line (1988-2007) versus the blue line before 1945 (pre-aircraft). The plot shows notably fewer recent storms and shows recent activity more in line with historical (pre-1945) activity.

    A closeup, with a few comments, is here . The impact of the Tims on the recent record is clear. I added several comments on the pre-1945 period, lest the question of a peak(1930s)-to-peak(2000s) comparison arises. The 1930s through the mid-40s was a period of limited global commercial activity, due to the Great Depression followed by World War 2 (this was shown on an earlier graph on CA a few months ago). Fewer ships in the 30s and early 40s meant less chance of an encounter with weather of any sort, including tropical cyclones. I suspect that this affected storm reports.

    To me, this is further evidence of the problems with long-term comparisons of Atlantic storm counts and reinforces my view that improvements in storm detection are the main drivers, and perhaps the sole drivers, of the increase in reported Atlantic storms.

  376. bender
    Posted Dec 1, 2007 at 8:58 AM | Permalink

    David, are you interested in posting the raw and corrected numbers in a file? Would like to do little number crunching.

  377. David Smith
    Posted Dec 8, 2007 at 11:46 AM | Permalink

    Re #376 Will do. I’ll pull together an Excel spreadsheet with various time series, storms and otherwise

  378. steve mosher
    Posted Dec 8, 2007 at 12:15 PM | Permalink

    Assuming the distribution of tiny tims in the past was consistent with the present data
    both in frequency and location. How many ships would it have taken on average
    using

    http://en.wikipedia.org/wiki/Bayesian_search_theory

    to find them before they disappeared. Bender is that problem tractable?

  379. John Norris
    Posted Dec 8, 2007 at 7:46 PM | Permalink

    I noticed Dr Gray got his forecast in early for next years David Smith tropical storm count open:

    Link

  380. Phil.
    Posted Dec 8, 2007 at 9:52 PM | Permalink

    Re #379

    It appears that La Niña has relocated to the Atlantic!

  381. _Jim
    Posted Dec 8, 2007 at 10:56 PM | Permalink

    The 1930s through the mid-40s was a period of limited global commercial activity, due to the Great Depression followed by World War 2 (this was shown on an earlier graph on CA a few months ago). Fewer ships in the 30s and early 40s meant less chance of an encounter with weather of any sort, including tropical cyclones. I suspect that this affected storm reports.

    At the risk of being called a maverick, trolling or just being ‘way out there’, I want to introduce into the record the idea of ‘radio’ detection and direction and position of tropical storms, to wit, reception of the lightning produced.

    Contemporary work (highly instructive in the detail of the lightning, it’s location within a hurricane, etc.):

    Convective Structure of Hurricanes as Revealed by Lightning Locations

    Observations of Lightning in Convective Supercell Within Tropical Storms and Hurricanes

    I could find only two or three references from the 30’s, and I could find no Radioman’s reports entered in any ships log of loss of communication owing to overwhelming ‘static’ attributable to tropical storms or hurricanes (but I would not doubt that there are!)

    A few notes:
    – Personal observation has shown that storm ‘static’ has much geater range at lower frequencies such as would have been experienced on the (now deprecated) longwave 500 KHz ‘emergency’ telegraphy frequency as well as the several nearby ‘working’ frequencies.

    – Medium (AM Broadcast band) and Shortwave (High Frequency) operating at higher frequencies also are amicable to HF DF (Directional Finding) which of course was instrumental in WWII in locating U-boats when they surfaced and ‘phoned home’.

    – AM Voice ops eventually took place on the ‘emergency’ calling frequency of 2182 kHz; this too would have been susceptable to lightning static given a path over highly conductive seawater.

  382. Bernie
    Posted Dec 8, 2007 at 10:57 PM | Permalink

    #380
    Never underestimate the ability of the media to get it completely wrong.

  383. STAFFAN LINDSTROEM
    Posted Dec 9, 2007 at 1:10 PM | Permalink

    #382…Bernie…perhaps not that ridiculous…look att Filippo
    Turturici’s post #425 in unthreaded #26!! November had “La Niña”
    conditions in the northern part of mid Atlantic.If Mid Indian ocean would
    turn cool what could happen?? Ice for my drink, somebody!? BTW David
    you don’t need to excuse yourself for Tiny Storm-Tiny Tim analogy. Long
    before we were born was the saying of a storm in a glass of water, which
    I alluded to in my “Living room hurricane” “Vince” of 2005 [He wrote with
    a sardonic smile…]
    #381 _Jim…Reminds me as an old DX-er of early June of 1980 when warm/hot
    air advanced from Balticum/SE Europe over the Baltic. This warm front had strong
    thunderstorms both before it passed and in the warm air. In the night
    i tried to hear stations from Latin America in the 60m band 4750-5050 kHz
    or so but static noise was overwhelming. This weather also
    caused the deaths of 11 persons in a train accident(check: Signals malfunctioning not confirmed) since lightning
    had struck the signal system (possibly true, but not causing the accident)

  384. L Nettles
    Posted Dec 19, 2007 at 9:45 AM | Permalink

    The Numbers Guy at the Wall Street Journal comments on Hurricane Prediction

    The Numbers Guy

    A Hurricane Forecast’s Poor Track Record

    Imagine a baseball expert predicting the Mets’ win total each year of the team’s history. If he did no better than a prediction every year that the Mets would win 76 games — the average in their 46 seasons — he’d have no credibility. That’s essentially what has happened with a well-known annual hurricane forecast, but it nonetheless continues to get lots of press.

  385. bender
    Posted Dec 19, 2007 at 10:05 AM | Permalink

    #384 I disagree slightly.

    Reword:
    Imagine a baseball expert predicting the Mets’ win total each year of the team’s history. If he did no better than a prediction every year that the Mets would win 76 games — the average in their 46 seasons — he’d gain no additional credibility.

    i.e. He wouldn’t lose any credibility either.

    Loss or gain in credibility only happens if unusual events are incorrectly or correctly predicted. So 2007, not being unusual, is inconsequential.

  386. Phil.
    Posted Dec 19, 2007 at 10:52 AM | Permalink

    Re #385

    But as I recall Gray incorrectly predicted an unusual event, i.e. an active season 17 named storms (average 10).
    That’s like predicting a 100+ season and ending up with 80!

  387. steven mosher
    Posted Dec 19, 2007 at 12:06 PM | Permalink

    RE 385.. Bender if you want a real HOOT, have a look at gavin latest on RC. He is recommending
    that Ross’ hypothesis about UHI contamination can be tested by looking at GCM results.

    Essentially test Ross’s approach by looking at multiple runs of GCMs.

  388. steven mosher
    Posted Dec 19, 2007 at 12:47 PM | Permalink

    re 385. Say hello to information theory, entropy, and the value of suprise.

    Someday I explain how this relates to art, novelty, noise, and change in fashion.

    For now I ask the philosophical question ” why is there noise rather than nothing”

  389. MarkW
    Posted Dec 19, 2007 at 12:57 PM | Permalink

    387:

    This does seem to be the teams modis operandi. If the data does not match the models, fix the data.

  390. steven mosher
    Posted Dec 19, 2007 at 1:23 PM | Permalink

    re 389. epistemically speaking you are always free to choose data or theory or verse vica

  391. Jeremy Friesen
    Posted Dec 19, 2007 at 1:54 PM | Permalink

    bender 385

    Loss or gain in credibility only happens if unusual events are incorrectly or correctly predicted. So 2007, not being unusual, is inconsequential.

    If I understand you: Scientist A could predict that every one of the next 100 years will have 300% of the yearly average of hurricanes. 1 of the years meets this prediction, and 99 don’t. They are all “not unusual”. Therefore Scientist A has not lost credibility since the other 99 years were not unusual, but gains credibility for the 1 unusual year he got right? The fact that he ‘overestimated’ the prediction by 200% for 99 years doesn’t count against him?

  392. Nat Tut
    Posted Dec 19, 2007 at 3:24 PM | Permalink

    Okay Guys,
    Re:24
    yes i know that was a long time ago, but there is something you should know, it’s a dust cluod that caused that delay, i haven’t read you whole discussion yet, but right now you aren’t on good terms with any real scienctist, and please note that this dust cloud came from the Sahara desert and it is dimming the suns rays enough to make a difference, so, i think you all are smart enough to realize that because of this hurricane ferquencey is not going down, its just being delayed and here in Florida we regard that as a very good thing at the moment. My friend came here to esacpe Katrina and is now living here, because his house was unreconizable, his basketball goal outside was split in half! Anyway you should do a little more reseach, and this is advice from a scientist,
    Nat

  393. bender
    Posted Dec 19, 2007 at 6:25 PM | Permalink

    #391
    You understand what I’ve said taken out of context. Put it back in context of the WSJ article and you’ll realize that what I said is not as silly as you make it sound. The trick in forecasting is to correctly predict deviations from the mean. After all, any turkey can predict the mean expectation. You’d have to be dumber than a turkey to get the mean expectation wrong, which is the scenario you outline. Better?

    Baseball is not a good analogy for hurricane forecasting either. With 162 game schedule and a probability of winning of 0.5, it is easy to have perfect confidence that the mean expectation is 81 wins. The trick is then to predict when a given team is going to have a good year (say 100 wins) or bad year (say 60 wins). What turkey is going to guess 81 every year, when in some years you have a great team loaded with talent, experience, and proven pitching, and in other years you are rebuilding? i.e. It’s not just a stochastic process, it’s an evolutionary process. What turkey is going to predict less than 81 for the Yankees with their perenially high payroll? In contrast, hurricane occurrence is a physical process. Although it may be stationary, there is no theory telling you what the mean expectation is. Only past observation. If a hurricane forecaster predicts 14 hurricanes every year and that is the mean, and it turns out that deviations from the mean are indeed random noise, then they are doing as well as you can do in the prediction game. The issue is whether the deviations are in fact random, or whether they are affected by semi-predictable things like AGW trends, ENSO, shear, Saharan dust clouds, ITCZ, etc. To make gains in these areas you need to be predicting deviations from the mean.

    Basically, what I’m saying is that you need to beat the spread. Predicting Patriots over Dolphins is a no-brainer. It’s whether you can pick the upsets that really counts.

  394. Posted Dec 22, 2007 at 3:35 PM | Permalink

    Here are a couple of (mildly) interesting plots.

    The first is a bar chart of storm ACE distribution . Storms with an ACE less than 2.0 account for one-third of all tropical cyclones over the last 20 years while storms with an ACE less than 4.0 account for 50%. How many of these weaker storms would have been missed in earlier times?

    I’ll look for a clue on that by making a similar plot for 1926-1945, which is the period immediately prior to the start of recon and at a similar point in the AMM/AMO cycle.

    Another plot is Tiny Tim ACE . These are storms that were so weak and/or remote that they were undetected by historical means (ships, shore) and instead had to be detected by modern satellite, recon, buoys, radar, etc.

  395. Geoff
    Posted Dec 31, 2007 at 11:31 PM | Permalink

    It’s getting hard to keep up with all the issues/postings, but wanted to alert people to this study on Pacific tropical cyclones by Johnny Chan:

    Abstract

    This study attempts to determine the possible causes of the interannual variations of intense tropical cyclones (TCs, or typhoons) in the western North Pacific (WNP, defined here as the region 0–40°N, 120–180°E). It is found that such variations cannot be explained by those of sea-surface temperature averaged over the same region. Rather, in years with a high frequency of occurrence of intense typhoons (inferred from high values of accumulated cyclone energy, or ACE), both the dynamic and thermodynamic conditions in the atmosphere, especially in the southeastern part of the WNP, are favourable for the formation of TCs. On the other hand, these conditions are not conducive for TC formation in years with small number of intense typhoons (low values of ACE). The temporal coefficients of the empirical orthogonal functions of the relative vorticity anomalies in the lower troposphere, the vertical zonal shear and the moist static energy correlate very well with ACE. The ACE is also significantly correlated with the Nino3.4 SST anomalies. It is concluded that the interannual variations of intense typhoons in the WNP are likely caused to a large extent by changes in the planetary-scale atmospheric circulation and thermodynamic structure associated with the El Niño phenomenon.

    The introduction gives a clear context:

    Two recent papers (Emanuel, 2005; Webster et al., 2005) have claimed that the recent increase in sea-surface temperatures (SSTs) as a result of global warming is likely to be responsible to the concomitant increase in either the power dissipation (Emanuel, 2005) or the number of intense hurricanes and typhoons (Webster et al., 2005) through a direct forcing of enhanced thermodynamic energy supply. However, many papers in the past have failed to identify such relationships. For example, Evans (1993) found no relationship between SST and the maximum intensity of tropical cyclones (TCs). More recently, Wang and Chan (2002, hereafter WC02) found that SST anomalies (SSTAs) in the western North Pacific (WNP) have no relationship with the location of TC formation over the same region. Chan and Liu (2004, hereafter CL04) actually found a negative relationship between TC number and SST in the WNP. The latest paper by Michaels et al. (2006) further pointed out the lack of correlation between TC intensity and SST especially for intense TCs. Because of these apparently contradictory results, it is important to re-examine the variations of the activity of intense TCs to determine the possible causes of such variations.

    Dr. Chan investigates SST and El Nino as explanations and finds:

    Therefore, at least for the WNP, the annual ACE, and thus likely the annual number of intense TCs, is apparently not related to the May–November mean SST averaged over the entire tropical WNP. This is similar to the conclusion of WC02 and CL04 who pointed that annual TC activity in the WNP is not regulated by the SST in the region but rather controlled by the atmospheric circulation in the WNP, which is related to the Nino3.4 conditions.

    And finally:

    To conclude, the variations in the frequency of occurrence of intense typhoons on interannual time series are caused by changes in the planetary-scale circulations in the WNP mostly associated with the El Niño phenomenon. Such changes lead to variations in the local dynamic and thermodynamic conditions of the local atmosphere that become either more or less favourable for TC formation and development. It should be noted that because these conditions cannot explain all the variance in ACE, some other factors that control the variations of ACE still need to be identified.

    Ref:Johnny C. L. CHAN (2007)
    Interannual variations of intense typhoon activity
    Tellus A 59 (4), 455–460.,
    doi:10.1111/j.1600-0870.2007.00241.x (availble here) (free for the budget/library access challenged). Have a look at the whole free issue on TC’s here.

    Lot’s of fun reading!

  396. Gerhard H.W.
    Posted Jan 1, 2008 at 3:18 AM | Permalink

    Btw, have you read the new paper from William M Briggs on atlantic hurricane activity? His conclusion is: “Hurricanes have not increased in the North Atlantic: misuse of running means”

    Briggs, WM, 2007. On the changes in number and intensity of North Atlantic tropical cyclones. Journal of Climate. Accepted. (final draft here)

  397. Geoff
    Posted Jan 1, 2008 at 4:39 AM | Permalink

    Just to keep up with two “mainstream” articles:

    1) Water and energy budgets of hurricanes and implications for climate change
    2) Water and energy budgets of hurricanes: Case studies of Ivan and Katrina

    by Trenberth and Fasullo (joined by Davis in the 2nd article);

    The abstract of the first one:

    On the basis of simulations of hurricane Katrina in August 2005 with the advanced Weather and Research Forecasting (WRF) model at 4 km resolution without parameterized convection, empirical relationships are computed between the maximum simulated wind and the surface fluxes and precipitation and provide a reasonable fit to the data. The best track data set of global observed tropical cyclones is used to estimate the frequency that storms of a given strength occur over the globe after 1970. For 1990–2005 the total surface heat loss by the tropical ocean in hurricanes category 1 to 5 within 400 km of the center of the storms is estimated to be about 0.53 × 1022 J a−1 (where a is year) (0.17 PW). The enthalpy loss due to hurricanes computed on the basis of precipitation is about a factor of 3.4 greater (0.58 PW), owing to the addition of the surface fluxes from outside 400 km radius and moisture convergence into the storms typically from as far from the eye as 1600 km. Globally these values correspond to 0.33 W m−2 for evaporation, or 1.13 W m−2 for precipitation. Changes over time reflect basin differences and a prominent role for El Niño, and the most active period globally was 1989 to 1997. Strong positive trends from 1970 to 2005 occur in these inferred surface fluxes and precipitation arising from increases in intensity of storms and also higher sea surface temperatures. Confidence in this result is limited by uncertainties in the best track tropical cyclone data. Nonetheless, the results highlight the importance of surface energy exchanges in global energetics of the climate system and are suggestive of the deficiencies in climate models owing to their inadequate representation of hurricanes.

    They start by asking the right questions:

    What role, if any, do hurricanes and tropical cyclones have in our climate system? Why do hurricanes exist? These rather fundamental questions are the motivation for the research outlined here and have substantial implications for both our understanding and modeling of the climate system and its variability. For instance, if hurricanes do play a key role in climate, as many researchers suspect, and such storms are not well simulated in climate models [e.g., Yoshimura et al., 2006], then it means that climate models have basic errors as the tropical storm processes have to be compensated for in some other way. Moreover, clear answers to these questions are essential if we are to understand better how hurricanes are altered by and affect a changing climate.

    Theu go on to put this in context:

    It is suggested here that a primary role for hurricanes comes about because they are the only phenomenon that can effectively pump large amounts of heat out of the ocean, into the atmosphere, and disperse it to regions where it can be radiated to space, thereby mitigating the heat buildup that otherwise occurs. In this perspective, the organized strong surface winds in hurricanes sufficiently increase the surface evaporation such that the latent heat losses by the ocean can exceed 1,000 W m−2, which is an order of magnitude larger than the summertime climatological value. Although hurricanes can be analyzed in terms of vortex dynamics and the favorable conditions required for them to exist and develop, the more fundamental question is why those conditions develop in the first place? It is argued that at least somewhere around the tropics in summer, in the neighborhood of the highest sea surface temperatures (SSTs), is where the main tropical cyclone activity will be favored [e.g., Yoshimura et al., 2006]. The tradewinds are strongest away from that region and occur where the SST temperature gradients and associated surface pressure gradients are strong. There may be two or perhaps three such regions in the tropics in any season, but large-scale tropical dynamics associated with monsoonal and Walker circulations guarantees competition for the primary location and thus where conditions for storm formation and intensification will be most favorable. Less favorable regions suffer from vertical wind shear and atmospheric stability structures (such as inversions) associated with the atmospheric circulation that make conditions less conducive to vortex development [Latif et al., 2007].

    Trenberth refers to some of his earlier work and then comments on the imporatnce of TC’s:

    From the standpoint of the ocean, therefore, the tropical storm produces a net cooling, but it actually does much more. Emanuel [2001, 2003] review the evidence for the large effects of hurricanes on the uppermost 200–300 m of the ocean, in which a storm deepens the mixed layer by many tens of meters, and cools the SST locally by as much as 5°C. Most of the cooling is owing to entrainment caused by turbulence generated from the strong shear of the near-inertial currents across the base of the mixed layer. A detailed analysis by Walker et al. [2005] of the cold wake left behind hurricane Ivan in 2004 reveals SST cooling of 3–7°C in two areas along Ivan’s track, related closely to the depth of the mixed layer and upper ocean heat content. Similar results for hurricane Frances in 2004 are given by Chen et al. [2007] and for Katrina in 2005 by Davis et al. [2007].

    The potential AGW issue is given as follows:

    Emanuel [1987, 2003] argued that increasing greenhouse gases alter the energy balance at the surface of tropical oceans in such a way as to require a greater turbulent enthalpy flux out of the ocean (largely in the form of greater evaporation), thereby requiring a greater degree of thermodynamic disequilibrium between the tropical oceans and atmosphere. This theory provides a theoretical basis for expected changes in the observational record as global warming proceeds.

    After reviewing some of his own work (and a few others) showing increased rainfall in the US, they add:

    Observed changes in precipitation in hurricanes are uncertain, although Trenberth et al. [2007] suggest that rainfall rates may have increased of order 6 to 8% since about 1970 in association with increased water vapor in the atmosphere of about 4% over the global oceans[Trenberth et al., 2005] and warming. This is because of the dominant reliance of storms on the resident moisture in the atmosphere and the moisture convergence for precipitation and latent heating in storms.

    The concusions are long but two key comments:

    We have found that hurricanes pump a considerable amount of heat out of the oceans every year and that the amount is apparently generally increasing over time after 1970 and depends strongly on ENSO. These facts represent a fundamental role for hurricanes in the climate system. Palmén and Riehl [1957] estimated an energy export of 0.88 PW for “average” hurricanes, while for Bonnie [Braun, 2006] it was 1.34 PW. These values are consistent with ours which are extended to the global domain for all seasons. As our values do not include the contributions from tropical storms that do not reach hurricane strength, they are conservative in terms of the effects of tropical cyclones on the climate system. However, they are probably representative of the effects that are not included in climatologies because of lack of observations within hurricanes.

    and

    The main result of this work is that the net surface enthalpy flux from global hurricanes from 30°N to 30°S is 0.17 PW when the region within 400 km of the center of the storms is considered, or about 0.58 PW for the full domain of hurricanes. The storms act to systematically cool the ocean and thus play a vital role in climate. If the enhanced evaporation value inside 400 km radius were redistributed over the tropical ocean area from 30°N to 30°S it amounts to 0.9 W m−2 heat loss, or equivalently 0.7°C a−1 cooling over a 10 m thick layer. The evaporative cooling corresponding to the tropical storm precipitation amounts to 2.3°C a−1. Although this is a modest rate, it is a systematic cooling of the tropical ocean by hurricanes over about 40% of the globe, and in actuality is concentrated into perhaps just one fifth of that area. Globally, this corresponds to 0.33 W m−2 for evaporation, or 1.13 W m−2 for precipitation. Although these estimates are somewhat less than the human-induced radiative forcing (about 1.5 W m−2), the latter is larger than the actual radiative imbalance which is estimated to be 0.7 to 1 W m−2 [Hansen et al., 2005]. Also for comparison, the global ocean to 3000 m depth gained 1.45 × 1023 J [Levitus et al., 2005] from 1955 to 1998, or an average of 0.33 × 1022 J a−1, and most of this increase took place after 1970 at a rate of 0.5 × 1022 J a−1, which is very similar to the annual hurricane heat loss within 400 km of the storm centers.

    Since this post ais already so long, I’ll just include the abstract of the companion article:

    To explore the role of hurricanes in the climate system, a detailed analysis is made of the bulk atmospheric moisture budget of Ivan in September 2004 and Katrina in August 2005 from simulations with the Weather and Research Forecasting (WRF) model at 4 km resolution without parameterized convection. Heavy precipitation exceeding 20 mm h−1 in the storms greatly exceeds the surface flux of moisture through evaporation, and vertically integrated convergence of moisture in the lowest 1 km of the atmosphere from distances up to 1600 km is the dominant term in the moisture budget, highlighting the importance of the larger-scale environment. Simulations are also run for the Katrina case with sea surface temperatures (SSTs) increased by +1°C and decreased by −1°C as sensitivity studies. For hours 42 to 54 after the start of the simulation, maximum surface winds increased about 4.5 m s−1 (9%), and sea level pressure fell 11.5 hPa per 1°C increase in tropical SSTs. Overall, the hurricane expands in size as SSTs increase, the environmental atmospheric moisture increases at close to the Clausius-Clapeyron equation value of about 6% K−1 and the surface moisture flux also increases mainly from Clausius-Clapeyron effects and the changes in intensity of the storm. The environmental changes related to human influences on climate since 1970 have increased SSTs and water vapor, and the results suggest how this may have altered hurricanes and increased associated storm rainfalls, with the latter quantified to date to be of order 6 to 8%.

    There is considerable effort going on to find some adverse consequences of warmer SST, but I guess one less TC would reduce damage far more than a slight increase in rain in the remaining storms would increase it.

    Refs: 1) Trenberth K. E., J. Fasullo (2007), Water and energy budgets of hurricanes and implications for climate change, J. Geophys. Res., 112, D23107, doi:10.1029/2006JD008304.
    2),Trenberth K. E., C. A. Davis, J. Fasullo (2007), Water and energy budgets of hurricanes: Case studies of Ivan and Katrina, J. Geophys. Res., 112, D23106, doi:10.1029/2006JD008303

  398. Geoff
    Posted Jan 1, 2008 at 6:06 AM | Permalink

    Gerhard (#396),

    Thanks for the reference. Looks similar to Chunzai Wang’s article in press at GRL, “Global Warming and United States Landfalling Hurricanes” where they also find a downward trend in US landfalls (again depending on end points).

    Abstract

    A secular warming of sea surface temperature occurs almost everywhere over the global ocean. Here we use observational data to show that global warming of the sea surface is associated with a secular increase of tropospheric vertical wind shear in the main development region (MDR) for Atlantic hurricanes. The increased wind shear coincides with a weak but robust downward trend in U.S. landfalling hurricanes, a reliable measure of hurricanes over the long term. Warmings over the tropical oceans compete with one another, with the tropical Pacific and Indian Oceans increasing wind shear and the tropical North Atlantic decreasing wind shear. Warmings in the tropical Pacific and Indian Oceans win the competition and produce increased wind shear which reduces U.S. landfalling hurricanes. Whether future global warming increases the vertical wind shear in the MDR for Atlantic hurricanes will depend on the relative role induced by secular warmings over the tropical oceans.

  399. Posted Jan 1, 2008 at 2:39 PM | Permalink

    Re #395-398 Thanks for sharing the links. The Atlantic TC data is becoming quite worked-over with someone plowing a new furrow almost daily. The Chan paper looks consistent with what I’d call the classsical view, in which SST is but one of a number of factors affecting global storm activity.

    Regarding Trenberth’s paper, my sense is that tropical cyclones move a lot of water vapor upwards and outwards with (relatively) minimal residual cloud ( see satellite image )and perhaps minimal residual water vapor. My guess is that this is due to the great heights to which the water vapor is carried, cooled and “dried”. This may have less impact (in cirrus and clear-air water vapor) than moving the same amount of moisture upwards and outwards by conventional tropical thunderstorms.

  400. scp
    Posted Jan 2, 2008 at 10:53 AM | Permalink

    Has this been discussed? A google search within climateaudit didn’t find it…

    Is Global Climate Change Affecting Hurricanes?
    Prof. Kerry Emanuel, Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology

    Produced by: American Meteorological Society
    August 27, 2007

  401. Posted Apr 1, 2008 at 8:42 PM | Permalink

    In case this hasn’t been posted, here is a funny April Fools spoof on the hurricane wars from Jeff Masters.

    You may recognize CA’s occasional Judith Flurryfury, Peter Webcaster and Steve McIntyre’s new stomping ground of the Georgia Institute of Technophobia. Kudos to the “victims” for their sense of humor (I hope).

    I love the “Journal of Irreproducible Results”.

    (Steve M, could you give us a new thread for 2008 hurricanes (it’s about time for the seasonal contest), or should we move to the side threads?)

  402. Posted Apr 1, 2008 at 9:12 PM | Permalink

    Is it my imagination or does Chris Landsea look like the American comedian Chevy Chase? Here’s a comparison . I wonder if Chris does pratfalls.

    Maybe they’re all actors. It’d be a bummer to learn that your PhD advisor for all these years was actually a comedian, doing climatology just for chuckles.

  403. Kenneth Fritsch
    Posted Apr 2, 2008 at 9:07 AM | Permalink

    Re: #400

    Has this been discussed? A google search within climateaudit didn’t find it…

    I believe that Kerry Emanuel’s views on TCs are well known by many posters here and have been discussed in a general context many times. Dr. Emanuel would appear to the leading theoretician in the Webster, Holland, Curry school of thought on TC’s and GW. As a layperson, I think his theoretical analysis are more respected and better received than his experimental analysis.

    Re: #397

    As I recall Emanuel has written about TCs/hurricanes having a significant affect on climate. I believe his conjectures about super hurricanes of the past (when it was warmer) and future (when it will be warmer) indicate that these large storms were (will be) a major means of conveyance of heat from the tropics to, eventually, space, i.e. a negative feedback for global warming.

    I read somewhere that Emanuel and other researchers were looking for proxies going back in time that might show evidence of super hurricanes.

    Re: #401 and #402

    David, if you put Jeff Master’s image of Chris Landsea (bland) together with your comparison of him with Chevy Chase, I think one can make a case for Landsea’s articles and remarks being done with deadpan humor. Once you have the expectation of the deadpan, like in the case of CC, you will begin falling down with laughter after reading a Landsea paper/comment.

  404. Judith Curry
    Posted Apr 2, 2008 at 3:40 PM | Permalink

    I agree, new thread for 2008 needed. By the way, Emanuel’s argument (http://wind.mit.edu/~emanuel/anthro2.htm, halfway down the page) for for the overestimation of major hurricanes prior to 1970 in the hurdat data set (basically in accord with Landsea 1993 paper) seems to be now generally accepted (including by Landsea). Note this is not April fool joke :) Professor Flurryflurry

  405. Reference
    Posted Apr 3, 2008 at 4:13 AM | Permalink

    Perhaps someone could summarize the 2007 thread in terms of the skill of forecasting and the contribution of AGW.

  406. MarkW
    Posted Apr 3, 2008 at 4:40 AM | Permalink

    Little and None.

  407. Kenneth Fritsch
    Posted Apr 3, 2008 at 11:34 AM | Permalink

    So which is it Professor Flurryflurry or Dr. Curry? I am thinking that a Dr. Curry would feel obliged to provide some concrete background information and sources for the Emanuel and Landsea comments — and particularly so in a thread that has shown evidence that much of the increasing trends in NATL TC frequency and intensity (ACE) can be attributed to increasing detection capabilities via Easy to Detect Storm indexes.

  408. Kenneth Fritsch
    Posted Apr 3, 2008 at 12:13 PM | Permalink

    Actually the thread with the most comprehensive discussion of changing TC and measuring capability trends is in the thread “YTD Hurricane Activity” where David Smith and Bob Koss presented much information in line with a claim that trends are due primarily to increasing detection capabilities. I will reference some summarized analyses below and ask other posters for alternative explanations for the results. The table (from Post #663) is one put together in looking for correlations between SST, wind shear and 925hPa wind velocity. The graph is from Bob Koss (see Post #663) and shows that presumably easier to detect storms have a nearly flat trend over time.

    I also find it troubling when paper/article writers talk about 1970s to current trends in the NATL when a look at the longer time series shows a decadal cyclical component in the series. Invariably these authors make little mention of this trough to peak condition nor to the global conditions.

  409. Posted Apr 3, 2008 at 9:25 PM | Permalink

    We’re less than two months from the start of the 2008 Atlantic season and the start of the seasonal forecasts. It’s almost contest time, in which the wizards among us can match forecasting wits with the masters.

    Last year we had a problem with the naming of anything-that-swirled, inflating the seasonal count. I suspect that will happen again in 2008. So, I propose that we use a different measure of forecasting prowess.

    That measure is ACE, which is a function of storm count, duration and intensity. Rather than forecast a numerical value of ACE I suggest that we forecasters nominate ranges (normal, below-normal, much below-normal, above-normal or much above-normal).

    Here is the 1948-2007 ACE values, grouped into the five ranges. There are (about) 12 storms per category.

    Feedback is appreciated. Is this the way to go? Are the groupings correct?

    Last year the CA forecast ensemble did as well as the ensemble “mainstream pros” forecasts.

    The deadline for forecasting the 2008 season will be June 1, except for the Europeans, who have until 2014 to make their 2008 forecast. The timeframe will be June 1 to November 30.

    Thoughts?

    Thanks

  410. Jonathan Schafer
    Posted Apr 4, 2008 at 10:04 AM | Permalink

    I think #409 should be the start of the 2008 Hurricane thread.

    That said, I would propose one contest with two parts. Part one would be a storm count total. This would keep us in line with the way everyone else pretty much forecasts the upcoming season. Part two would be based on your suggestion above, for ACE estimation by category. The “Grand Champion” would be the person closest in both categories, with second place finishers for total storm count and most accurate ACE.

  411. Kenneth Fritsch
    Posted Apr 4, 2008 at 10:17 AM | Permalink

    Re: #409

    The deadline for forecasting the 2008 season will be June 1, except for the Europeans, who have until 2014 to make their 2008 forecast. The timeframe will be June 1 to November 30.

    Thoughts?

    The Europeans, on whose predictions for the 2007 season I placed one half of my prediction/bet at CA, does not use ACE so I will be in a quandary as how to formulate my 2008 prediction. And, by the way, I have not been able to find the other 2/3 of the 2007 predictions that go into the “European” prediction. The UK Met Office did it right by predicting prior to the season, but I have not been able to find Meteo-France and EW….(?) predictions even after the season is long ended. Should this delay be a concern or did they perhaps simply misplace their predictions or forget to announce them?

    Seriously, I would favor using the ACE index for predicting purposes – not that that will give me more confidence in mine or others’ predictions, but it should cut-off all the naming and claiming comments.

  412. Michael Jankowski
    Posted Apr 4, 2008 at 11:27 AM | Permalink

    “Experts: No link between hurricanes, warming”

    http://www.miamiherald.com/news/breaking_news/story/483052.html

  413. Posted Apr 4, 2008 at 11:45 AM | Permalink

    Since the Emanuel 2005 and Webster et al. 2005 papers hit the presses, global hurricane activity has collapsed and has reached historically low levels. The decreasing trend largely began after the monumental El Nino of 1997-1998 and has continued through March 2008 with low ACE levels last seen in 1977. In the Atlantic Ocean, there is both an increasing trend in SST (MDR) and ACE (high from 1950s-1960s, low in 1970s-1980s, high again since 1995) in a low-frequency sense. Anyplace else on our globe?

    Mind-bender: When I regress North Atlantic ACE since 1977 on global sea surface temperatures (August-October), I can get the same relationship between MDR SST : NATL ACE as Southwest Pacific SST (during SH winter!) : NATL ACE.

    Since 1995, the Eastern Pacific (except for 1997 El Nino) activity has collapsed. Is it a coincidence that EPAC + NATL ACE are anti-correlated with R = -0.9 during the past 15 years? It is this EPAC activity collapse that is completely forgotten by Emanuel, Webster et al., Holland, etc. that explains a lot about the current TC conundrum.

    Before we take Ted Turner’s advice and prepare for cannibalism, perhaps we should understand how TCs operate in the current climate, a rejoinder echoed by many recently.

  414. Larry T
    Posted Apr 4, 2008 at 12:15 PM | Permalink

    If all it takes to reduce hurricaine activitiy was for Emanuel and Webster to publish papers then maybe they should have published long ago.

  415. Bob Koss
    Posted Apr 4, 2008 at 12:34 PM | Permalink

    I’m fine with using ACE.

    Since it is only for the June-November timeframe I did up a couple graphs just for Atlantic storms that started during that time period. It uses all ACE values for the storms even if they extend into December. No May storms extending into June are included.

    Point of interest. June to November ACE during 1950 exceeds 2005. The 1950 season activity was entirely between Aug 12th and Oct 21st, while 2005 data goes from June 8th to January 7th.

  416. Kenneth Fritsch
    Posted Apr 4, 2008 at 1:40 PM | Permalink

    From the link in Michael Jankowski’s link:

    Chris Landsea, a respected researcher and the National Hurricane Center’s science officer, told attendees of the National Hurricane Conference that there is no conclusive evidence that global warming has significantly enhanced or otherwise affected the number or intensity of hurricanes.

    This April 4, 2008 article would seem to go against Judith Curry’s indication that Chris Landsea had finally seen the light on past hurricane intensity measurements being over estimated or am I missing some nuanced meanings here?

    The Bob Koss ACE bar graph sure shows the “V” effect of past tropical storm activity that bottoms out in the early 1970s — which just happens to often jibe with the statement “if one looks at SST versus NATL hurricane intensity from 1970 to present we see….” Sometimes we hear added that that starting time is used because the measurements are puportly better starting then, but not that often is noted what lays prior to that time.

    I think it is time to do a change point analyis on the ACE time series, using the ACE reported for all storms and that for the Easy to Detect Storms.

  417. Kenneth Fritsch
    Posted Apr 8, 2008 at 6:09 PM | Permalink

    Below is linked the CSU NATL TC forecast for the 2008 season and some comments that confirm my earlier analyses that showed that the early CSU forecasts have no skill but that skill increases as the forecasts get closer to the event. In other words, forecasting the future weather/climate for inputs into the model is more difficult than fitting existing conditions into a model to predict outcomes.

    I have become entirely frustrated by my inability to obtain the 2007 predictions for NATL TC activity from Meteo France and ECMWF. Does anyone know why these predictions are so difficult to come by for the 2007 season? These are part of Met Office UK, Meteo France and ECMWF ensemble of dynamical models that have been highly touted by, not only their own organizations, but by Judith Curry here at CA.

    http://www.wunderground.com/education/seasonal2007.asp

    It’s going to be a modestly more active than average Atlantic hurricane season in 2008, according to the December seasonal forecast issued by Dr. Bill Gray and Phil Klotzbach of Colorado State University (CSU). The CSU team is calling for 13 named storms, 7 hurricanes, 3 intense hurricanes, and an ACE index 20% above average (Accumulated Cyclone Energy (ACE) is a measure of the total destructive power of a hurricane season, based on the number of days strong winds are observed). An average season has 10 named storms, 6 hurricanes, and 2 intense hurricanes. The CSU forecast calls for a 15% above average chance of a major hurricane hitting the U.S. The odds for a major East Coast hurricane are put at 37% (a 31% chance is average), and odds for the Gulf Coast are 36% (30% chance is average). The CSU team predicts that the current moderate La Nina event will weaken by the 2008 hurricane season, but still contribute to lower than average values of wind shear. In addition, warm sea surface temperatures are likely to continue in the tropical and North Atlantic during 2008, due to the fact that we are in a positive phase of the Atlantic Multidecadal Oscillation (AMO), which began in 1995.

    ..For the first time, the CSU team presents detailed information informing users of the accuracy of their December forecasts. Past December forecasts by CSU have had no skill, and I’ve criticized them for not clearly stating this. I applaud their efforts in today’s forecast, where it says in the 2nd paragraph of the abstract, “These real-time operational early December forecasts have not shown forecast skill over climatology during the period 1992-2007″. Later in the report, they show that the correlation coefficient (r squared), a standard mathematical measure of skill, is near zero for their December forecasts. As an example of this lack of skill, consider the figures presented in the November 2007 verification report. This report stated that 65% of their December forecasts between 1999 and 2007 correctly predicted whether the coming hurricane season would be above or below normal, for forecasts of number of named storms, hurricanes, intense hurricane, and number of days these storms were present. That 65% figure sounds pretty good, but is it skillful? To answer that question, I tallied up how an almost zero-skill forecast would have done over the same period. My almost zero-skill forecast simply assumed that since we are in an active hurricane period that began in 1995, every hurricane season will have an above normal number of named storms, hurricanes, intense hurricanes, and number of days storms are present. The result? My almost zero-skill forecast got it right 65% of the time, exactly the same as the CSU December forecast.

    ..Another way to measure skill is using the Mean Square Skill Score (MSSS), which looks at the forecast error and squares it, then compares the percent improvement the forecast has over a climatological forecast of 10 named storms, 6 hurricanes, and 2 intense hurricanes (Figure 1). The skill of the December forecasts issued by both CSU and Tropical Storm Risk, Inc. (TSR) have averaged near zero since 1992. Not surprisingly, the forecasts get better the closer they get to hurricane season. The TSR forecasts show more skill than the CSU forecasts, but it is unclear how much of this superiority is due to the fact that TSR issues forecasts of fractional storms (for example, TSR may forecast 14.7 named storms, while CSU uses only whole numbers like 14 or 15). TSR does an excellent job communicating their seasonal forecast skill. Each forecast is accompanied by a “Forecast Skill at this Lead” number, and they clearly define this quantity as “Percentage Improvement in Mean Square Error over Running 10-year Prior Climate Norm from Replicated Real Time Forecasts 1987-2006.”

    ..The June and August forecasts from CSU, TSR, and NOAA show some modest skill, and are valuable tools for insurance companies and emergency planners to help estimate their risks.

  418. Posted Apr 8, 2008 at 7:24 PM | Permalink

    Gray’s forecast update comes out tomorrow, April 9, 2008…

  419. steven mosher
    Posted Apr 8, 2008 at 7:32 PM | Permalink

    2008 THREAD PLEASE AND THANK YOU.

    sorry fer shoutin

  420. Posted Apr 8, 2008 at 8:24 PM | Permalink

    TSR has issued their April forecast for the Atlantic: 15 storms and an ACE of 136. That ACE value qualifies as an “above-average” season by the guidelines of post #409.

    The dynamical models should be able to see into the heart of the hurricane season (August-September) by now. Perhaps they could give us a peek at the future and let us know how bad it’ll be.

  421. David Smith
    Posted Apr 21, 2008 at 12:01 PM | Permalink

    A final comment on the 2007 season (maybe):

    The report for Tropical Storm Erin (2007) has finally been issued. It was delayed for quite a while.

    I suspect that the delay was due to the writers examining whether the remains of Erin, a very minor storm that entered Texas and immediately weakened to a depression, regenerated into a tropical storm nearly 600 miles later in landlocked, semi-arid west-central Oklahoma.

    They decided “no”, but only after debating the topic (see report).

    Imagine Steve Sadlov’s consternation had they decided to declare it to be the first-ever Land-cane (“Lano-caine” sounds better but I think it’s taken)

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