US hikes storm forecast as Gulf season nears peak
8/5/2011 12:00:00 AM
“The atmosphere and Atlantic Ocean are primed for high hurricane activity during August through October,” said Dr. Gerry Bell, lead seasonal hurricane forecaster at the Climate Prediction Center.
“Storms through October will form more frequently and become more intense than we’ve seen so far this season,” he added.
That would continue a recent trend, in which two of the past three seasons have been above average. In 2008, Hurricane Gustav in Louisiana and Hurricane Ike in Texas significantly disrupted energy industry operations.
Just last week, Tropical Storm Don shut in as much as 12% of offshore oil output in the Gulf of Mexico.
Key climate factors predicted in May continue to support an active season, the forecasters said. These include: the tropical multi-decadal signal, which since 1995 has brought favorable ocean and atmospheric conditions, leading to more active seasons; exceptionally warm Atlantic Ocean temperatures (the third-warmest on record); and the possible redevelopment of La Niña.
Reduced vertical wind shear and lower air pressure across the tropical Atlantic also favor an active season.
Based on these conditions and on climate model forecasts, the confidence for an above-normal season has increased from 65% in May to 85 %. Also, the expected number of named storms has increased from 12-18 in May to 14-19, and the expected number of hurricanes has increased from 6-10 in May to 7-10.
Across the entire Atlantic Basin for the whole season - June 1 to November 30 - NOAA’s updated seasonal outlook projects, with a 70% probability, a total of:
• 14 to 19 named storms (top winds of 39 mph or higher), including:
• 7 to 10 hurricanes (top winds of 74 mph or higher), of which:
• 3 to 5 could be major hurricanes (Category 3, 4 or 5; winds of at least 111 mph)
These ranges are indicative of an active season, and extend well above the long-term seasonal averages of 11 named storms, six hurricanes and two major hurricanes.
The Atlantic basin has already produced five tropical storms this season: Arlene, Bret, Cindy, Don and Emily.
The last hurricane to make landfall in the United States was Ike in 2008, which significantly disrupted downstream operations in Texas and Louisiana.
Last year saw above-normal hurricane activity, but none made landfall in the US.
August through October are peak months of the Atlantic hurricane season, and US agencies said they are urging people not to be lured into a false sense of security by the lack of hurricanes so far this year.
To see the full NOAA report, click here.
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