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Hurricane Forecasters Stick to "Busy" 2008 Prediction

Willie Drye
for National Geographic News
June 3, 2008
 
Even as the first named storm of the season is being blamed for four deaths in Belize, forecasters at Colorado State University (CSU) are sticking to their April prediction of a busy Atlantic hurricane season for 2008.

The CSU team today released an updated forecast that predicts eight hurricanes—four of them with winds exceeding 110 miles (177 kilometers) an hour—will form before the season ends November 30.

"Conditions in the tropical Atlantic look quite favorable for an active hurricane season," CSU forecaster Phil Klotzbach said in a prepared statement.

Klotzbach and CSU colleague William Gray think a total of 15 tropical storms will form in the Atlantic Basin, which includes the Caribbean Sea and the Gulf of Mexico (see map).

Tropical Storm Arthur, the season's first, came ashore Saturday along the Mexico-Belize border.

Although the storm was weakening as it made landfall, heavy rains triggered flash floods that swept away houses and wiped out bridges, according to the Associated Press.

Arthur has since been downgraded to a tropical depression.

East Coast Landfall?

Hurricanes draw their energy from warm waters, and Klotzbach said this year's unusually warm sea-surface temperatures—along with the absence of upper-level winds known to inhibit storm formation—could contribute to an active season.

Long-term yearly averages are nine or ten named storms, six of which are hurricanes, and two of which are intense hurricanes.

In April the CSU forecasters had said there is a 70 percent likelihood that a major hurricane will make landfall somewhere on the U.S. East Coast.

But they did not speculate about where the hurricane is likely to come ashore.

Over the past hundred years, the likelihood of the East Coast being hit by a major hurricane has been about 50 percent.

Gray, who has been issuing long-range hurricane forecasts for decades, told National Geographic News in April that the summer of 2008 will continue a trend of above-average hurricane seasons that started in 1995.

The stormier summers have been due to ocean currents that increase the Atlantic's salt content, which in turn increases water temperatures.

The fluctuations are cyclical, with warming and cooling cycles typically lasting about 30 years.

Gray acknowledged, however, that CSU forecasters "haven't done too well with our forecasts for the last couple of seasons." (Read about last year's off-target forecasts.)

Gray and Klotzbach predicted 17 named storms for the 2007 season, but only 14 formed. A 15th storm formed in May 2007, several weeks before the official start of the season.

The lower-than-expected activity last year was caused by a high-pressure system that formed off the East Coast late in the season, Gray added.

Cape Verde

Keith Blackwell is a meteorologist at the Coastal Weather Research Center at the University of South Alabama in Mobile.

In April he told National Geographic News that he saw important indications that the summer of 2008 could be stormier than last year.

Blackwell noted at the time that water temperatures were well above normal off Cape Verde on the west coast of Africa.

Some of the worst hurricanes in history have started as storms off Cape Verde.
 

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