Bad hurricane season ahead

With no help from El Nino, bad storm season ahead
By Katie Sanders, Times Staff Writer
The Atlantic hurricane season begins June 1 and runs through Nov. 30. The experts are predicting it will be busier than usual, with 14 to 20 named storms, about twice as many as last year. Four of those are expected to pack winds of 111 mph or more. While forecasters don't always agree on the precise number of storms in a coming season, they all agree this is shaping up to be a bad one. Here's a look at the four main factors driving these predictions.
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1. LA NINA VS. EL NINO: The most important conditions used to determine hurricane activity are also the toughest to predict, said Jeff Masters, founder of wunderground.com. However, scientists have noticed a rapid transition over the past month toward a La Nina cycle, which basically shifts atmospheric circulation and creates weak upper level winds in the Atlantic Basin. Unlike an El Nino cycle, these winds from the west are not strong enough to disrupt hurricane formations. "This year we're done with El Nino, so that's not going to help us," Masters said.
Trade winds from the east push warm surface waters, red and orange, to the western Pacific. Hurricanes in the Atlantic are a greater threat in this scenario.
The trade winds weaken and allow the warm surface water to flow back to the eastern Pacific. This leads to high-level winds that can shear the tops off hurricanes.
2. SEA SURFACE TEMPERATURE: High sea-surface temperatures fuel storms, making them more powerful. March and April had the highest sea-surface temperatures on record in the tropical Atlantic, Masters said, and the Atlantic hurricane basin is in a decades-long active warming phase.
3. BERMUDA HIGH: When it centers over Bermuda, this high-pressure mass in the Atlantic acts like a goalkeeper during the summer by steering hurricanes away from Florida. In 2009, a Bermuda high did not stretch over Florida, forcing storms to curve out to the sea and miss us, Masters said. When hurricanes head toward the Gulf of Mexico, it means the air mass has extended farther west over the state. The Bermuda high cannot be predicted more than a week or two in advance, so it’s too soon to tell how it will influence this season.
4. AFRICAN DUST: Dust blowing off Africa's west coast could discourage hurricane activity by blocking or absorbing sunlight, cooling the Atlantic. Scientists track rainfall off the coast to determine if dust will fend off storm activity. This works during periods of below-normal rain, which create drought conditions and allow wind to pick up dry soil. But Africa has had normal rains for the past three years. "I'm not expecting dust to help us out this year," Masters said.
Source: www.osdpd.noaa.gov
STEVE MADDEN, JOHN CORBITT | Times
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