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NOAA Predicts Above-Average Hurricane Season

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By NEIL JOHNSON

The Tampa Tribune

Published: May 23, 2008

TAMPA - Conditions are in place for an active hurricane season, with government scientists predicting an above-average number of storms in 2008.

Twelve to 16 named storms this season are expected during the June 1 to Nov. 30 season, six to nine of which might become hurricanes, said Gerry Bell, lead seasonal forecaster with the National Climate Prediction Center.

Bell also said two to five of those hurricanes could grow to Category 3 or stronger, with winds of 111 mph to 130 mph.

The team of scientists from the National Oceanic and Atmospheric Administration that put together the season's forecast does not pinpoint a number of predicted storms nor where they might hit, if anywhere.

NOAA's prediction would mean a season with more hurricanes than average, which is 11 named storms, six hurricanes and two major hurricanes.

The prediction follows a trend of more active seasons that started in 1995, Bell said. The Atlantic Ocean entered a phase of more active hurricane seasons 13 years ago that could last another 12 to 27 more years.

"There's no indication this period has ended," Bell said as NOAA unveiled its seasonal prediction at MacDill Air Force Base, where the agency's two hurricane hunter aircraft are based.

La Nina Lingers

In addition to the period of heightened hurricane activity, Bell said lingering effects on the atmosphere of a La Nina pattern also pointed to a more active season.

During a La Nina, water in the equatorial Pacific Ocean cools a few degrees below normal. The pattern causes shifts in the jet stream that reduce hurricane-busting winds. Seasons during a La Nina typically have more hurricanes than when the Pacific is at its normal temperature or warmer than normal.

This year, NOAA officials emphasized that any forecast may not be 100 percent accurate. Bell said agency scientists are 60 to 70 percent certain the number of storms will be within the forecast range. But there's a 25 percent chance of a near-normal season and 10 percent possibility the season will produce fewer than normal storms.

Last year, NOAA predicted 13 to 17 named storms, seven to 10 hurricanes and three to five major storms with winds topping 111 mph, or Category 3. The number of storms was within NOAA's predicted range, but the season produced only six hurricanes and just two reached major storm strength.

Those were hurricanes Dean and Felix, which became the first two Category 5 hurricanes to hit land in the same season since modern records started in 1850.

Most storms last season did not become strong or last long. One hurricane, Humberto, hit the United States in 2007 as a Category 1 storm that shrank to a tropical storm after landfall in Texas.

Bell said 2007 was a busy hurricane season, but the prediction was flawed in other ways.

"What missed was the overall intensity and duration of the storms," he said.

NOAA didn't do enough to make the public understand that any forecast has a possibility of being wrong, said Louis Uccellini, director of the National Centers for Environmental Prediction that includes the center were Bell works.

"We don't have the skill level to predict the exact number of storms," Uccellini said. "But climate conditions point to an active season."

The Africa-Amazon Connection

Those conditions include rainfall in tropical west Africa and the Amazon basin, Bell said. Rain that is above average in Africa and below average in the Amazon creates winds in the atmosphere favorable for hurricanes, and that has happened since the Atlantic entered the active phase in 1995.

NOAA's expectations mirror the April seasonal forecast by William Gray and Phil Klotzbach of Colorado State University. They forecast 15 named storms, with eight becoming hurricanes and four of those growing into major storms.

Gray and Klotzbach will issue a revised forecast June 2, the day after hurricane season starts. NOAA will revise its forecast in August when hurricane season begins its busiest 10 weeks.

Reporter Neil Johnson can be reached at (813) 259-7731 or njohnson@tampatrib.com.

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