Newspaper article The Christian Science Monitor

Hurricane Fred Veers off. Why the US Has Been Spared So Far

Newspaper article The Christian Science Monitor

Hurricane Fred Veers off. Why the US Has Been Spared So Far

Article excerpt

The hurricane season may be dead in the water.

Hurricane Fred - the second hurricane and fifth named storm of the 2009 Atlantic storm season - grew into one of the strongest storms ever in the east Atlantic on Wednesday, but is now veering off toward the open north Atlantic where it's likely to soon dissipate.

Despite favorable hurricane conditions off the African coast, a surprise El Nino effect in the Pacific is cutting down oncoming storms from the East, forecasters say.

"We're getting these hurricane seedlings that are trying to make it across Atlantic ... but they're getting annihilated" by El Nino- spawned westerlies in the upper atmosphere, says Keith Blackwell, a storm forecaster at University of South Alabama's Coastal Weather Research Center in Mobile. The storms, he said, are "getting a crew cut."

Predictions about an "active" hurricane season have dissipated like a late summer thunderstorm since last month, when hurricane Bill washed beachgoers off some rocks in Maine. Forecasters have already downgraded the season to "below-average."

Going into this hurricane season, which usually runs until November, US experts had predicted 12 named storms, with six turning into hurricanes and two becoming major. But veteran storm predictor William Gray at Colorado State University, Fort Collins pulled back those predictions last week, calling for a "below-average" season of 10 storms, including four hurricanes, two of them major.

El Nino's impact

The surprise El Nino effect - a warm water system along the northwestern South American coast - has caused upper atmospheric prevailing winds (the jet stream) to shift south, weakening hurricanes by shearing off the their tops.

"It's these intense storms that come out of the deep tropics that El Nino activity tends to weaken a great deal," says Professor Gray. Researchers typically can't detect the extent of El Nino activity until late spring or early summer, complicating long-term hurricane predictions. …

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