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Posted at 12:30 PM ET, 04/08/2009

CSU Hurricane Outlook Foresees Average Season

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Colorado State University (CSU) hurricane experts Drs. Phil Klotzbach and Bill Gray have adjusted their seasonal tropical forecast downward in an update released yesterday:

We foresee average activity for the 2009 Atlantic hurricane season. We have decreased our seasonal forecast from our initial early December prediction. We anticipate an average probability of United States major hurricane landfall.

The hurricane forecasting duo predict 12 named storms (average is 10-11), 6 hurricanes (average is 6), and 2 intense hurricanes (category 3 or higher; average is 2). Their earlier outlook called for 14 named storms, 7 hurricanes, and 3 intense hurricanes.

Keep reading for more on this outlook...

The primary rationale Klotzbach and Gray give for lowering the number of expected storms from their earlier outlook are cooling sea surface temperatures (with respect to average) and the increasing possibility of a developing El Nino -- which tends to inhibit tropical activity.

The Klotzbach and Gray outlook also projects the likelihood of storms hitting certain large regions. Here is their summary:

PROBABILITIES FOR AT LEAST ONE MAJOR (CATEGORY 3-4-5) HURRICANE LANDFALL ON EACH OF THE FOLLOWING COASTAL AREAS:
1) Entire U.S. coastline - 54% (average for last century is 52%)
2) U.S. East Coast Including Peninsula Florida - 32% (average for last century is 31%)
3) Gulf Coast from the Florida Panhandle westward to Brownsville - 31% (average for last century is 30%)
4) Average major hurricane landfall risk in the Caribbean

The reliability of these outlooks is a source of contention. Although Klotzbach and Gray successfully predicted last year's active season in April, Wunderground's Jeff Masters points out "their April forecasts have had negative skill between 1995-2008. In other words, you would have been better off using climatology than believing their April forecasts." But Klotzbach and Gray, noting they have improved the methods for these outlooks in the last several years, claim "it is possible to say something about the probability of the coming year's hurricane activity which is superior to climatology."

Klotzbach and Gray's outlook is quite similar to the other outlooks that have been issued this season. AccuWeather's Joe Bastardi predicts 13 named storms (8 hurricanes) and WeatherBug predicts 11-13 named storms (6-8 hurricanes). British private forecasting firm Tropical Storm Risk, Inc., whose outlook was released Monday, is calling for 15 named storms and 8 hurricanes.

Taken together, the four outlooks issued all predict 11-15 storms and 6-8 hurricanes. When there is strong consistency between forecasts, that usually increases the likelihood they're right. But given the subpar past performance of these kinds of outlooks, they should still be taken with a grain of salt.

By  |  12:30 PM ET, 04/08/2009

Categories:  Tropical Weather

 
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