AccuWeather's 2011 hurricane forecast is out
The first spring forecast for the 2011 Atlantic Hurricane Season is out. AccuWeather.com’s Paul Pastelok expects “an active season with more impact on the U.S. coastline than last year.”
He predicts 15 named tropical storms, with eight reaching hurricane strength, and three becoming “major” (Cat. 3) storms. That’s more than average, but less than 2010’s third-busiest 19, 12 and 5. Since no hurricane made U.S. landfall in 2010, predicting a “higher potential” this year seems a safe bet.
The season officially begins June 1 and lasts through November. Here's the 2010 storm track map. Click to enlarge.
Last year, AccuWeather.com's Joe Bastardi predicted 16 to 18 named storms, a few short of the final count. He also compared the conditions for 2010 to those preceding the 1964, 1995 and 1998 seasons, all of which, he noted, saw major impacts on the U.S.
Pastelok bases this year's predictions on several factors. These include the El Nino/La Nina cycle in the Pacific. We're currently in a waning La Nina, and Pastelok expects it will be in a neutral phase by summer - not cycling into the warm-water El Nino conditions in the tropical eastern Pacific, which tend to produce stronger westerly winds in the Atlantic.
"Stronger westerlies would prohibit major storms, or a lot of storms, so it is a critical factor," he said.
Saharan dust is another factor. When it blows west out over the Atlantic, it can inhibit storm formation. "Current projections ... suggest there will be episodes of dust affecting development, but no more than normal," Pastelok said.
He also factors in the Atlantic Multidecadal Oscillation. This is a long-term cycle of Atlantic surface water temperature and atmospheric factors. It has been in a positive, warm-water phase since 1994, and that has meant generally more active hurricane seasons than the historic average.
Pastelok believes the early part of the season will see the highest risk for the western Gulf of Mexico and the southern Caribbean. By the mid- and late-season months, the risk will shift to the eastern Gulf and Caribbean, as well as the Florida peninsula and the Atlantic coast from Florida to the Carolinas.
(NASA PHOTO: Hurricane Igor, September 2010)