El Nino is a shift of warm ocean water in the Pacific Ocean, but can have profound effects on the weather in North America. It has helped to shut down the Atlantic Hurricane Season with faster tropical winds aloft, and may also enhance the cold jet stream this winter. That is expected to plunge into the southeast and lead to a cold and stormy winter. Will that translate to snow for us? That is a tough call. In about half of El Nino winters, Baltimore can get well above normal snowfall... above 33 inches. Yet the other half can end up with well below normal snow. Other factors do come into play, but it appears likely that we are over due to heavy snow.
Here is the report from NOAA just released:
El Niño in the central and eastern equatorial Pacific Ocean isexpected to be a dominant climate factor that will influence theDecember through February winter weather in the United States,according to the 2009 Winter Outlook released today by NOAA’s ClimatePrediction Center. Such seasonal outlooks are part of NOAA’s suite ofclimate services.
“We expect El Niño to strengthen andpersist through the winter months, providing clues as to what theweather will be like during the period,” says Mike Halpert, deputydirector of the Climate Prediction Center – a division of the NationalWeather Service. “Warmer ocean water in the equatorial Pacific shiftsthe patterns of tropical rainfall that in turn change the strength andposition of the jetstream and storms over the Pacific Ocean and theU.S.”
“Other climate factors are also likely to playa role in the winter weather at times across the country,” addedHalpert. “Some of these factors, such as the North Atlantic Oscillationare difficult to predict more than one to two weeks in advance. The NAOadds uncertainty to the forecast in the Northeast and Mid-Atlanticportions of the country.”
Highlights of the U.S. Winter Outlook (December through February) include:
- Warmer-than-average temperaturesare favored across much of the western and central U.S., especially inthe north-central states from Montana to Wisconsin. Though temperaturesmay average warmer than usual, periodic outbreaks of cold air are stillpossible.
- Below-average temperaturesare expected across the Southeast and mid-Atlantic from southern andeastern Texas to southern Pennsylvania and south through Florida.
- Above-average precipitationis expected in the southern border states, especially Texas andFlorida. Recent rainfall and the prospects of more should improvecurrent drought conditions in central and southern Texas. However,tornado records suggest that there will also be an increased chance oforganized tornado activity for the Gulf Coast region this winter.
- Drier-than-average conditions are expected in the Pacific Northwest and the Ohio and Tennessee River Valleys.
- Northeast:Equal chances for above-, near-, or below-normal temperatures andprecipitation. Winter weather in this region is often driven not by ElNiño but by weather patterns over the northern Atlantic Ocean andArctic, such as the North Atlantic Oscillation. These patterns areoften more short-term, and are generally predictable only a week or soin advance.
- California: A slight tilt in the odds toward wetter-than-average conditions over the entire state.
- Alaska:Milder-than-average temperatures except along the western coast. Equalchances for above-, near-, or below-median precipitation for most areasexcept above median for the northwest.
- Hawaii: Below-average temperatures and precipitation are favored for the entire state..
Thisseasonal outlook does not predict where and when snowstorms may hit ortotal seasonal snowfall accumulations. Snow forecasts are dependentupon winter storms, which are generally not predictable more thanseveral days in advance.
