WSI increases its Atlantic hurricane season forecast from 15 to 18 named storms

[News_Editor]

WSI increases its Atlantic hurricane season forecast from 15 to 18 named storms

2011-08-25 08:04:08 GMT+7 (ICT)

ANDOVER, MASSACHUSETTS (BNO NEWS) -- Weather Services International (WSI) on Wednesday said it now expects 18 named storms during the 2011 Atlantic hurricane season, a revision from 15 storms forecast in July.

WSI increased this year's hurricane season forecast from 15 to 18 named storms, of which eight are to become hurricanes and four major hurricanes (category 3 or greater). The numbers would be above the long-term average of 12 named storms, 7 hurricanes and 3 major hurricanes, and slightly higher than the average of the more active recent period.

WSI Chief Meteorologist Todd Crawford said "Before Irene, this season had been characterized by a slew of weak/moderate tropical storms. To date, we have already had 9 named storms; and we're still two to three weeks away from the mid-point of the season."

Crawford stated that their 18 named storms forecast may be too low given the current pace and that the remainder of the hurricane season should be quite active. However, the atmosphere in much of the tropical Atlantic has been less unstable than normal, limiting the strength of the storms which have formed, avoiding their development to hurricanes.

Although WSI increased its forecast for the total number of named storms, the forecaster maintained its expectation of 8 hurricanes and 4 major hurricanes. "Irene is just the first hurricane of the season," he said.

According to the U.S. National Hurricane Center (NHC), Irene has strengthened over the Bahamas and has now been upgraded to a category three hurricane. It already made landfall in Puerto Rico on Monday and it is expected to intensify and hit the U.S. East Coast on Friday, possibly as a major hurricane.

Crawford further indicated that the Gulf Coast, after Irene, is under the greatest threat for hurricane landfall for the remainder of the season. The United States has been avoiding land falling hurricanes in the recent years, and the last hurricane to make landfall in the United States was Ike in 2008 which killed nearly 200 people.

This good fortune is largely due to a negative phase of the North Atlantic Oscillation (NAO). This atmospheric pattern was primarily responsible for re-curving Irene before she got into the Gulf.

However, the WSI expects the North Atlantic blocking pattern to relax as September arrives which may open the Gulf up to an increased threat of hurricane landfalls. "Multiple U.S. landfalls would not be particularly unusual, because the mean number of U.S. landfalls since 1995 has been 2.26. Further, the western Gulf States have averaged 0.94 landfalls a season since 1995," Crawford said as he recommended the U.S. coastal area inhabitants to prepare for the ongoing hurricane season.

Earlier this month, on August 4, NOAA's Climate Prediction Center (CPC), a division of the U.S. National Weather Service, also updated its hurricane season forecast, saying it expects 14 to 19 named storms in the Atlantic this year, a revision from 12 to 18 storms forecast in May. Of these, CPC expects seven to ten becoming hurricanes and three becoming major hurricanes.

WSI will release its final update for the 2011 tropical season on September 21.

An average Atlantic hurricane season produces 11 named storms, with six becoming hurricanes and two becoming major hurricanes. The Atlantic hurricane season runs from June 1 through November 30, with peak activity in September.

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