Hurricane Season Forecast Above Average: Can We Trust It?

Seasonal hurricane forecasts have something in common with successful rain dances:  timing is everything.

The problem with hurricane forecasts is that a lot of people get up and start dancing before there is a cloud in the sky -- before the ocean and atmospheric conditions that make one season more active or dangerous than another are in place.

So every year in March and April, forecasters begin issuing predictions about the character of the upcoming hurricane season. And the media spreads the word as if these prognostications are credible, official -- or at least, semi-official --estimates of what the large, exposed populations along the Gulf Coast and Eastern Seaboard can expect in the months ahead.

There is an air of unreality about all of this, because year-in and year-out, these long range early forecasts of the June-to-November hurricane seasons notoriously miss their marks.  Here's what Philip J. Klotzbach and William M. Gray had to say about their widely publicized seasonal forecast issued this week:  "Everyone should realize that it is impossible to precisely predict this season’s hurricane activity in early April."  They could have added that it is also impossible to imprecisely predict this season's hurricane activity in early April, and let it go at that.

Instead, they went on for 43 pages, satisfying what they describe as "much curiosity as to how global ocean and atmosphere features are presently arranged as regards to the probability of an active or inactive hurricane season for the coming season."

For what it is worth, Klotzbach and Gray predicted a significantly above average 2010 season, which begins June 1 and runs through November.  There will 15 named tropical storms, including 8 hurricanes, including 4 major hurricanes, they predict, and a 69 percent chance that one of the big ones will hit somewhere along the US coastline.

Among the chorus of early prognosticators, you won't find the people you might expect to hear from -- the scientists and other specialists at the National Weather Service, the National Hurricane Center or, for that matter, the Climate Prediction Center, which does not issue a seasonal outlook until May 20.

"A number of the variables that would influence the development of tropical cyclones for the season do not show themselves until April and early May," observed Dennis Feltgen, a National Hurricane Center spokesman.  In a nutshell, that comment describes what scientists call "the spring barrier" -- a time of unstable transition when important meteorological factors are largely unknown and evidently unknowable.

Maybe these early forecasts, however inaccurate, are harmless diversions from the worries of the day, but you have to ask yourself:  Is it a good idea for all of us to become accustomed to discounting the credibility of warnings about impending hurricanes?  And even if they are perfectly accurate, what exactly is the value of this information to someone inhabiting this big hurricane-exposed coastline?

Feltgen wasn't asked these questions, but it is fair to say that the subject has come up behind closed doors at the National Hurricane Center and elsewhere.  "Our message at NHC is that, while the seasonal outlook does have some skill in the overview of the season, it should not be used as a guide for preparation plans by those living along the vulnerable coastal areas," he said.  "It only takes one storm hitting your area to make it a bad year, regardless of the number of storms that are forecast in the seasonal outlook."

Map shows all of the hurricanes in the Atlantic Basin since 1851 and in the eastern North Pacific since 1949. Courtesy of the National Hurricane Center.