Hurricane Forecast Revised Downward

Willie Drye
for National Geographic News

August 3, 2006

Forecasters at Colorado State University (CSU) have reduced the number of tropical storms they think will form in the Atlantic this season. But they still predict that three major hurricanes will form before November 30.

CSU forecasters Phil Klotzbach and William Gray said this morning that 15 named storms will form in the Atlantic Basin, which includes the Caribbean Sea and the Gulf of Mexico.

Of those storms, seven will develop into hurricanes with winds of at least 74 miles (119 kilometers) an hour. Three will evolve into major storms with winds of at least 111 miles (178 kilometers) an hour, they say.

In May, the forecasters had said this hurricane season would be "very active," producing five major storms between June 1 and November 30.

Lull Before the Storm?

The 2006 season seems quiet in comparison to the raucous summer of 2005, when an unprecedented 28 named storms formed.

So far in 2006 there have been only three named storms. By this time last year two major hurricanes had already formed in the Atlantic.

Forecasters warn, however, that this year's relative calm is no reason for coastal residents to drop their guard.

"Last year was an exception," said Lixion Avila, a forecaster at the National Hurricane Center (NHC) in Miami, Florida. "Last year the ocean was very warm. This year it's not as warm as last year."

Hurricanes derive their power from warm ocean water. (See an interactive feature on how hurricanes form.)

Still, ocean temperatures this summer are slightly above normal, says NHC forecaster James Franklin.

In 2005 the Atlantic was 3 or 4 degrees Fahrenheit (1.7 to 2.2 degrees Celsius) above normal. This year, the water is about 1 degree Fahrenheit (0.5 degree Celsius) above normal.

The NHC will release a revised forecast for the 2006 season on August 8.

Number of Factors

CSU's Gray, a pioneer in long-range hurricane forecasting, said in a prepared statement that the relatively quiet beginning to the 2006 season did not prompt CSU forecasters to reduce their prediction.

"We're not reducing the number of hurricanes because we had only two named storms through late July," Gray said. "It's a general erosion of a number of factors.

"The tropical Atlantic sea-surface temperatures are not quite as warm, tropical Atlantic surface pressure is not quite as low, the eastern equatorial Pacific has warmed some, and trade winds in the tropical Atlantic are slightly stronger," he said.

The CSU forecasters also think the U.S. Atlantic Coast is the most likely place to see a landfall.

"This year it looks like the East Coast is more likely to be targeted by Atlantic Basin hurricanes than the Gulf Coast, although the possibility exists that any point along the U.S. coast could be affected by a hurricane," Klotzbach said.

Willie Drye is the author of Storm of the Century: the Labor Day Hurricane of 1935, published by National Geographic Books.

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