In the final forecast update to the U.S. winter outlook, NOAA Climate Prediction Center forecasters remain confident in predicting 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. “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:
*Temperatures are expected to be above average 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, 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 Great Lakes and Tennessee Valley, temperatures and precipitation should both be above average.
*The south-central Plains should see drier-than-average conditions and warmer-than-average temperatures. Above-average temperatures are also expected in the central Plains. The northern Plains has equal chances of above-, near-, or below-average temperature and precipitation.
*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.
*Northern Alaska is expect to be milder than average, while the rest of
*Alaska has equal chances of above-, near-, or below-average temperatures and precipitation.
*In Hawaii, precipitation is expected to be above average with above average temperatures in the western Islands. The eastern islands have equal chances of above-, near-, or below-average temperatures
For the country as a whole, NOAA's heating degree day forecast for December through February projects a 4.0 percent warmer winter than the 30-year normal, which is very similar to last winter.
“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,” said Edward O’Lenic, chief, forecast operations, NOAA Climate Prediction Center. “We encourage people to review winter weather risks for their particular area and information available online to help keep them safe when events do occur.”
The U.S. winter outlook is produced by a team of scientists at the Climate Prediction Center in association with NOAA-funded partners. Scientists base this forecast on long-term climate trends and a variety of forecast tools from statistical techniques to extremely complex dynamical ocean-atmosphere coupled models and composites.
NOAA will announce the U.S. Spring Outlook in March 2008.