Above-Average Hurricane Season Will Strike Next Year, Colorado State Says

Colorado State University researchers predict an above-average storm season for the Atlantic in 2011, forecasting at least 17 named storms and nine hurricanes, five of them major.

The early extended-range forecast today from the team led by William Gray and Phil Klotzbach also predicted more hurricanes will make landfall in the U.S. next year. There is a 73 percent chance at least one of them will be a “major” storm, with winds of 111 mph (179 kph) or higher, they said in an e-mail.

The Atlantic hurricane season is closely watched because the storms are a threat to oil and natural gas interests in the Gulf of Mexico and agriculture in the Southern states. Florida is the second-largest citrus producer behind Brazil, and the Gulf accounts for 31 percent of U.S. oil output and 43 percent of the country’s refining capacity.

This year, 19 storms received names, which happens when winds hit 39 mph, and 12 of them became hurricanes with winds of 74 mph or more. An average season has 11 named storms, according to the National Oceanic and Atmospheric Administration.

In their forecast as the season began in June, Gray and Klotzbach called for 18 named storms and 10 hurricanes. Last December, they predicted 16 named storms, with eight becoming hurricanes.

U.S. ‘Lucky’

The 2010 hurricane season was the third-most active in history. It ended eight days ago.

“The U.S. was extremely lucky in 2010 in that none of the 12 Atlantic basin hurricanes that formed crossed the U.S. coastline,” Klotzbach said in the e-mail. “On average, about one in four Atlantic basin hurricanes makes U.S. landfall, and therefore we would expect to see more landfalling hurricanes in 2011.”

The odds are near even that a major hurricane will strike the East Coast, including Florida, and the Gulf Coast between the Florida Panhandle and Brownsville, Texas, CSU said.

This year’s storm activity was affected by a La Nina, or cooling of the Pacific Ocean. The phenomenon cuts down on wind shear in the Atlantic that can prevent storms from forming.

Pacific Temperatures

Gray said the CSU team can’t forecast yet whether the La Nina will continue. However, he said it is unlikely that there will be a return to the Pacific warming known as an El Nino, which can hinder storm growth.

In 2008, when a La Nina faded and the Pacific returned to normal, 16 named storms formed and the U.S. was struck by six consecutive tropical systems, according to U.S. National Hurricane Center records.

Some forecasters believe that the La Nina may linger into at least July or August. When a La Nina is active, hurricanes tend to form farther to the east in the Atlantic, which can mean they track away from the U.S. mainland, said Tom Downs, a meteorologist with Weather 2000 Inc. in New York.

In 2010, the U.S. received only one direct strike, when Tropical Storm Bonnie crossed southern Florida before dissipating in the Gulf of Mexico. Canada, Mexico and Central America all received direct hits from much more powerful storms that killed hundreds of people and caused at least $1.6 billion in damage.

To contact the reporters on this story: Brian K. Sullivan in Boston at Bsullivan10@bloomberg.net; Charlotte Porter in New York at ’ Cporter11@bloomberg.net

To contact the editor responsible for this story: Dan Stets at dstets@bloomberg.net

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