The 2008 hurricane season is likely to be less kind to the United States than the one that ended officially last week, according to forecasters at Colorado State University.

For next season, which begins June 1 and ends Nov. 30, they foresee 13 named storms - those with winds of 39 m.p.h. or better - one fewer than this year.

But the forecasters, Philip Klotzbach and William M. Gray, warn of a high likelihood that at least one major hurricane, with winds of 111 m.p.h. or more, will make U.S. landfall, which did not happen this year.

The 2007 season left an early holiday present for U.S. taxpayers.

Not a single major disaster was declared for a hurricane this year, according to Ashley Small, spokeswoman for the Federal Emergency Management Agency.

By contrast, FEMA has committed $37.8 billion to cleaning up hurricane damage from the 2005 season - about $350 for every U.S. household. The total for 2006 was $2.6 billion.

Not that the 2007 season was without drama. For the first time on record, two deadly Category 5 hurricanes, with winds over 160 m.p.h. - Dean and Felix - made landfall in the same season.

Yet only one full-fledged hurricane, Humberto, reached the U.S. mainland, and it was a Category 1, with a peak wind of 90 m.p.h.

Klotzbach and Gray said the odds of a major hurricane hitting the United States next year were about 15 percent above normal.

They also predicted a more vigorous season overall in terms of storm intensity and duration. They say they expect seven hurricanes, storms with winds of 74 m.p.h. or more, or one more than average.

Researchers are trying to figure out what happened during a 2007 season that got off to a strong start, then faded at September's end. The Colorado State team and the National Oceanic and Atmospheric Administration had issued menacing forecasts.

Joe Bastardi, hurricane forecaster for Accu-Weather Inc. in State College, Pa., cited one obvious explanation for the lack of U.S. landfalls in 2007 - "a bit of luck."

Gerry Bell, a NOAA forecaster, said the outcome was particularly perplexing given the alignment of La Niña, a generally active hurricane era and warm waters in the western Atlantic.

La Niña, a cooling of water in the equatorial Pacific, usually coincides with busy seasons, especially during those 25- to 40-year cycles of enhanced hurricane activity, such as the one now.

Bell says he believes the big factor was increased vertical wind shear that snuffed out potential monster hurricanes before they could grow. He said the wind shear might have been related to heavy rains in Southeast Asia.

Citing work by Evan Amato, a University of Wisconsin scientist, the Colorado team said that atmospheric dust stirred by storms off the Sahara Desert may have had a hand in dampening the season.

Powerful Saharan dust storms create a "Saharan air layer" that covers the upper atmosphere all the way to the Caribbean and obscures warming sunlight.

Amato said that while dust-storm activity was minimal in August and September, it was brisk in May, June and July.

Amato's hypothesis is that the dust blocked sunlight and contributed to a cooling of the tropical Atlantic surface, making it unfavorable for heat-seeking hurricanes.

He warns the dust likely won't be as plentiful in 2008.

Contact staff writer Anthony R. Wood at 610-313-8210 or twood@phillynews.com.