NOAA 98-R239                                     9/24/98
                                       
CONTACT:
Curtis D. Carey

If La Nina conditions strengthen in the tropical Pacific Ocean, they will impact precipitation and temperature patterns in the next three to six months, according to a scientist with the National Oceanic and Atmospheric Administration.

Speaking at special La Nina briefings, Dr. Gerry Bell, research meteorologist at the National Weather Service Climate Prediction Center, said strengthening La Nina conditions would mean, "The southern United States can expect a drier, warmer and less stormy winter due to the effects of La Nina through the spring." This dryness might intensify already existing drought conditions in the deep South.

According to Bell, "Texas, New Mexico and Oklahoma will likely be drier and warmer. "Georgia and Florida will also likely be drier and warmer.

"Louisiana, Mississippi and Alabama will likely be warmer, but near normal precipitation is expected during the months of January, February and March 1999."

As a further departure from the dryness trend in the southern part of the United States, "Arkansas and Tennessee will likely be wetter and warmer," Bell said.

La Nina reflects cooler than normal sea surface temperatures across the eastern half of the tropical Pacific, whereas during El Nino, the ocean waters in that region are warmer than normal. The last strong La Nina occurred in the winter of 1988-89.

Armed with graphic reviews of conditions in the tropical Pacific Ocean, Bell explained how the National Weather Service Climate Prediction Center conducts its state-of-the-art research. According to Bell, the center monitors La Nina and El Nino with a network of buoys and satellites operated by the National Oceanic and Atmospheric Administration. He also explained how La Nina impacts the weather throughout the world.

"These temperature changes affect global wind and air pressure patterns and our world's climate, as well as the location of marine life," Bell said. "El Nino and La Nina have always been a naturally occurring part of our global climate system. Thanks to widespread research efforts throughout the world and recent advances in technology, our observing and forecasting capabilities have significantly improved in the past few years."

The current La Nina began developing in the eastern half of the tropical Pacific in late May and June 1998, with ocean temperatures dropping up to 10 degrees Fahrenheit in that period, signaling the end of the 1997-98 El Nino cycle.

According to the latest advisory issued by the Climate Prediction Center on Sept. 10, moderate La Nina conditions are expected to develop and persist for the remainder of 1998 and continue into the spring. This outlook is consistent with forecast models being run by other research institutions around the world.

For more information on NOAA's Climate Prediction Center and its forecasts, visit our Web site at: http://nic.fb4.noaa.gov