NOAA U.S. WINTER OUTLOOK UPDATE
Oct. 21, 2004 ó NOAA today updated its U.S. Winter Outlook for December 2004 through February 2005, which continues to call for warmer-than-normal conditions in the West and Alaska, and cooler-than-normal conditions in the South and in sections of the mid-Atlantic coast states. (Click NOAA image for larger view of forecast winter temperatures for the USA. Click here for high resolution version, which is a large file. Please credit “NOAA.)
For precipitation, NOAA's Outlook calls for drier-than-average conditions in the Pacific Northwest and Ohio Valley and wetter-than-average conditions over parts of the South. In Hawaii, temperatures are expected to be above average with precipitation below average. Elsewhere, there are equal chances of above, below and normal temperatures.
Currently, NOAA is monitoring a weak El Niño in the tropical Pacific, which is expected to continue into early 2005. However, NOAA scientists predict this El Niño will remain much weaker than the 1997-1998 El Niño event. (Click NOAA image for larger view of forecast winter precipitation for the USA. Click here for high resolution version, which is a large file. Please credit “NOAA.)
"El Niño wintertime impacts over the United States vary considerably depending on the character of the warming in the tropical Pacific," said Vernon Kousky, NOAA's lead El Niño/Southern Oscillation forecaster. "While we are carefully monitoring this current El Niño episode, we are expecting other climate patterns to play an equally important role in this winter's weather."
NOAA scientists say the leading climate patterns expected to impact this winter's weather are long-term climate trends and features such as the El Niño/Southern Oscillation (ENSO) and the Pacific/North American pattern (PNA), which influence the jet stream and the track storms take across the eastern Pacific and North America. In addition, the North Atlantic Oscillation (NAO) can affect winter weather in the Northeast by altering the jet stream over the North Atlantic and adjacent areas. “These climate patterns are the physical basis for this season's winter outlook and updates like the one presented today,” said Wayne Higgins, principal climate scientist at the NOAA Climate Prediction Center.
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Relevant Web Sites
Drought Information Center