Five storms into the 2011 Atlantic hurricane season and with tropical storm Emily bearing down on Haiti, NOAA has upped its prediction for the amount of tropical activity this year. Whereas its late May outlook forecast 12-18 total named storms, it now expects 14-19. And it nudged up its projection for hurricanes to 7-10 from 6-10.
“The atmosphere and Atlantic Ocean are primed for high hurricane activity during August through October,” said Gerry Bell, Ph.D., lead seasonal hurricane forecaster at NOAA’s Climate Prediction Center.
In May, NOAA was bullish for an active season as a result of the following factors :
1) The active (mult-decadal) Atlantic hurricane era that began in 1995 continues
2) Ocean waters warmer than average
3) La Nina conditions - though expected to weaken - reduce the wind shear hostile to storms (often seen during El Nino years)
These three favorable climate factors all remain in place. For example, ocean temperatures in the Atlantic basin are exceptionally warm, presently third warmest on record. In addition, wind shear levels and pressures are generally low, supporting tropical development. And even though La Nina has waned this summer, NOAA indicates it may redevelop this fall, which would further help keep hostile wind shear under wraps.
Considering all of the above along with computer model forecasts, NOAA’s confidence for an above-normal season has increased from 65 percent in May to 85 percent. And it assigns a 70% probability to its overall forecast of 14-19 named storms, 7-10 hurricanes, and 3-5 major hurricanes (category 3 or higher).
“Storms through October will form more frequently and become more intense than we’ve seen so far this season,” said Bell.
NOAA and the FEMA are both urging preparedness as the U.S. has not had a direct hit from a hurricane since Ike in 2008. As we wrote in June, despite above average tropical activity the last several years in the Atlantic, the U.S. is in a historic hurricane landfall drought :
* It’s now been more than 1,000 days since any hurricane (irrespective of intensity) has struck the U.S. mainland.
* The last major hurricane to strike the U.S. coast was Wilma in October, 2005, coming ashore in southwest Florida.
These stretches are among the longest on record.
Both and NOAA and tropical storm experts are united in the sentiment that the “luck” of the U.S. coast is bound to run out.