Wednesday, November 21, 2007

Winter forecast for the US: above average temperatures, Southern drought

Environment News Service: In the final update to the U.S. winter outlook, the NOAA Climate Prediction Center is forecasting above average temperatures for much of the country, including southern sections of the Northeast, and below normal precipitation for the southern tier of the nation. Above average precipitation is still anticipated for the Pacific Northwest, and in the Great Lakes and Tennessee Valley.

"La Niña strengthened during October, making it even more likely that the United States will see below-average precipitation in the already drought-stricken regions of the Southwest and the Southeast this winter," said Michael Halpert, deputy director of the Climate Prediction Center. La Niña is a periodic cooling trend of the surface waters in the eastern tropical Pacific Ocean.

Halpert said, "Recent sea surface temperatures indicate we have moderate La Niña conditions in place over the equatorial Pacific which we expect to continue into early 2008." On average, for December 2007 through February 2008, NOAA seasonal forecasters predict above average temperatures in the Mid-Atlantic states and southern sections of the Northeast in response to the long-term warming trend.

La Niña favors drier than average conditions along the mid-Atlantic coast. As always, says Halpert, snowfall for the region will depend on other climate factors, which are difficult to anticipate more than one to two weeks in advance. The drought-plagued Southeast is likely to remain drier than average due to La Niña, while temperatures are expected to be above average.

…In the Northwest, there are equal chances for above, near, or below average temperatures. Precipitation should be above average in much of the region due to La Niña. Much of California is anticipated be drier than average in response to La Niña, while there are equal chances of above, near, or below average temperatures. Drought conditions are expected to persist in the Southwest due to La Niña, and temperatures are likely to be above average.

…For the country as a whole, from December through February NOAA forecasters project a 4.0 percent warmer winter than the 30 year normal, which is very similar to last winter's temperatures. But earmuffs and snow tires will still be needed in many parts of the country.

Edward O'Lenic, chief, forecast operations, NOAA Climate Prediction Center, said, "Although we are expecting a warmer than normal winter, we do believe there will be fluctuations of warm weather and typical winter weather throughout the season."

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