The 2008 North Atlantic hurricane season was the fourth most active since detailed records began and this was accurately forecast by the Met Office. Richard Graham, climate specialist at the Met Office, said: “For two years running our model has given accurate guidance on tropical storm numbers, and we aim to build on that success this year.

“Our capability in this emerging area shows how the science of climate change can be used to help us today, as well as in the future.”

The Met Office uses a dynamical numerical model of the climate system, known as GloSea, to create the forecast. This technique of modelling atmospheric processes to predict tropical storm activity ahead of the season is a departure from traditional methods, which use statistical data.

Here is the graphic from their page and some text that goes along with it:

Issued 18 June 2008

15 tropical storms are predicted as the most likely number to occur in the North Atlantic during the July to November period, with a 70% chance that the number will be in the range 10 to 20. This represents above-normal activity relative to the 1990-2005 long-term average of 12.4.

I need to see more evidence of “forecasting” success than just two seasons before I start applauding the utility of climate models for seasonal forecasting. Since the climate model can’t resolve the tropical cyclones themselves, an adjustment process is applied to get the forecast number. This adjustment is a function of previous season’s activity and is essentially an analogue method.

Can Hurricane Activity be predicted out to 5-years with skill? (No!)

But, the flashback to the 2005 RMS elicitation has the 4 expert scientists associated with the crummy forecasts. This also links back to Prometheus.

Roger nailed all of this well over 2-years ago. Thank goodness Florida didn’t accept that RMS elicitation at that time and jack up insurance rates 40%.

Our contestants chose of one five ACE groupings (“much below average, below average, average, above average or much above average”), each of which corresponded to a 20% quantile of ACE (1950-2007). This year the season’s ACE was 141, which falls into the “above-average” quantile.

In recognition of their accomplishment I offer this collector’s edition Certificate of Achievement to the six forecasters who correctly predicted an “above average” season ACEwise:

Among the six there are three who deserve special acknowledgment. They are ma in va, whose ACE forecast was the closest (140 forecast vs 141 actual); Kenneth Fritsch who was close behind (145 vs 140) and who also forecast the exact number of hurricanes, and Steven Mosher who offered additional forecasts of other aspects of the season, most of which were close to the mark.

Congratulations to those who came close and thanks to everyone who participated. Let’s hope these forecasters will share their secrets of success here at CA.

You make some interesting points.It would appear to me that the African Easterly Waves seems to be solar heat driven and whether they end up generating a high or low storm and hurricane season in the Atlantic or Caribbean depends on the ENSO conditions coming from the Pacific.You can compare the years 2005 and 2008. Both years were ENSO neutral, both had more than average number of storms and hurricanes but the solar heating as shown by the temperature data in my judgement was significantly more in 2005.The conditions were ideal for a record storm season , namely an unusually strong and steady African Easterly wave with little or no oppostion or interference from the Pacific ENSO effect. A similar condition existed in 1995 with neutral and weak La Nina conditions during the latter part of the year and warm solar heating.[11hurricanes]

Tropical storms develop when conditions permit and usually in little cocoons of favorable atmosphere. The SSTs are always sufficient for genesis in the tropics from July – October. Positive SST anomalies on the local scale easily feed-back to the overlying atmosphere and may increase the favorability for genesis or intensification of storms. So, most Atlantic development probably can be attributed to how the climate deals with the African Easterly Waves.

I like it, David. The dice that inform as to the forecasting and placing them directly below Einstein was a nice touch and too clever by far.

I wanted to do a quick analysis of just how lucky my picks were (using the methods that I used). Also we need to keep in mind that selecting from a group of forecasters increases the odds for obtaining some close picks just by chance. I suppose if we wanted to be real sneaky we could do some averaging from ensemble forecasts.

My confessions would be more appropriate if I were to win the ACE contest but as of this writing my calcualtions show that the better Ma(n) won.