Ryan Maue writes in as follows (see also 2007 Tropical Cyclone Activity).
As reported at Climate Audit at the end of October, the North Atlantic was not the only ocean seeing quiet tropical cyclone activity. When using the ACE cyclone energy scale, the Northern Hemisphere as a whole is historically inactive. How inactive? One has to go back to 1977 to find lower levels. Even more astounding, 2007 will be the 4th slowest year in the past half-century (since 1958).
The 2007 Atlantic Hurricane season did not meet the hyperactive expectations of the storm pontificators. This is good news, just like it was last year. With the breathless media coverage prior to the 2006 and 2007 seasons predicting catastrophic swarms of hurricanes potentially enhanced by global warming a la Katrina, there is currently plenty of twisting in the wind to explain away the hyperbolic projections. The predominant refrain mentions something about being lucky and having escaped the storms, and just wait for next year.
Well before we prepare for the obvious impending onslaught of the next above-average hurricane season, lets review some very positive aspects of what 2007 offered:
When combined, the 2006 and 2007 Atlantic Hurricane Seasons are the least active since 1993 and 1994. When compared with the active period of 1995-2005 average, 2006 and 2007 hurricane energy was less than half of that previous 10 year average. The most recent active period of Atlantic hurricane activity began in 1995, but has been decidedly less active during the previous two seasons.
When combined, the Eastern Pacific and the North Atlantic, which typically play opposite tunes when it comes to yearly activity (b/c of El Nino), brushed climatology aside and together managed the lowest output since 1977. In fact, the average lifespan of the 2007 Atlantic storms was the shortest since 1977 at just over two days. This means that the storms were weak and short-lived, with a few obvious exceptions.
So, before throwing Dr. Gray, NOAA, and Accuweather under the bus, consider what seasonal forecasting must entail to skillfully project hurricane activity. Then consider what we do not know well:
Now, when a seasonal prediction is made, elements of the above questions enter into play: One, two, three, or six months ahead of the season, how many storms will form, how strong will they be, and what is the probability that any of those will affect land (particularly the United States). This requires knowledge of oceanic conditions half-way around the world, precipitation patterns over Africa, and a host of other considerations.
Nevertheless, do not lose heart. Long-range weather prediction is a booming enterprise, with energy, insurance, and governmental agencies investing considerable resources into this colossal effort. The house always wins.