Coming La Niņa Revs Up Atlantic Hurricane Season

CAMP SPRINGS, Maryland, September 11, 2007 (ENS) - Scientists with the National Oceanic and Atmospheric Administration's Climate Prediction Center say that a La Niņa weather pattern is forming in the eastern tropical Pacific Ocean.

As a result, seasonal forecasters expect wetter than normal conditions in the Pacific Northwest and drier than normal conditions in the drought-stricken southwestern United States this fall.

"These conditions also reinforce NOAA's August forecast for an above normal Atlantic hurricane season," said Gerry Bell, PhD, the agency's lead seasonal hurricane forecaster.

La Niņa refers to the periodic cooling of ocean surface temperatures in the central and east-central equatorial Pacific that occurs every three to five years. It is the opposite of the warming pattern known as El Niņo.

NOAA declares the onset of a La Niņa event when the three-month average sea-surface temperature departure exceeds -0.5 degrees Celsius (-0.9 degrees Fahrenheit) in the east-central equatorial Pacific.

"While we can't officially call it a La Niņa yet, we expect that this pattern will continue to develop during the next three months, meeting the NOAA definition for a La Niņa event later this year," said Mike Halpert, acting deputy director of the Climate Prediction Center in Camp Springs.

Meteorologists are observing below-normal sea surface temperatures across the central and eastern equatorial Pacific and stronger than average easterly winds across the west-central equatorial Pacific.

"Nearly all operational dynamical models, including the National Centers for Environmental Prediction's Climate Forecast System and many of the statistical models also favor a La Niņa event," said Halpert.

Meanwhile, the closely-watched Colorado State University hurricane forecasting team of Philip Klotzbach and William Gray said last week the hurricane season is far from over that they expect above-average activity for the remainder of the season.

The Colorado State September-only forecast calls for five named storms, four hurricanes, two major hurricanes and Net Tropical Cyclone activity of 80, which is well above the September-only average value of 48.

Their October-November forecast calls for five named storms, two hurricanes, one major hurricane and Net Tropical Cyclone activity of 42, which exceeds the October-November average value of 22.

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