By Scott Dance, The Baltimore Sun
5:30 PM EDT, October 18, 2012
A waffling El Nino has prevented U.S. government weather forecasters from repeating other weather watchers’ predictions of a snowy winter in Maryland — though they aren’t ruling one out.
The National Oceanic and Atmospheric Administration is forecasting equal chances of below- and above-average snowfall and temperatures in Maryland and the rest of the Mid-Atlantic and Northeast. That’s because what appeared to be a building El Nino earlier this year has reversed course in recent months, and it’s too early to say what other climate indicators could show, said Mike Halpert, deputy director of the NOAA’s Climate Prediction Center, which is based in a new facility in College Park.
“We’re not ruling out big snowstorms, but we’re not guaranteeing them either,” Halpert said.
The forecast could subdue some who were primed for a snowy winter (and give hope to the snow-haters). Forecasters like AccuWeather.com and The Farmer’s Almanac have called in recent months for above-average snowfall for the winter. Just about any significant snowfall would mean more shoveling than winter 2011-2012, when just 1.8 inches fell at Baltimore-Washington International Thurgood Marshall Airport, and a repeat of 2010’s epic snowfalls is unlikely.
Normal seasonal snowfall in Baltimore is about 21 inches, according to the NOAA.
While El Nino — a climate phenomenon linked to warmer-than-normal surface water temperatures in the Pacific Ocean — can cause major snowstorms in Maryland and surrounding regions, it doesn't affect broader winter weather patterns, Halpert said. A dry, warm winter is just as likely as a cold, wet one, he said.
The NOAA’s forecast predicts a 33 percent to 40 percent chance of higher-than-normal temperatures west of the Mississippi and of lower-than-normal temperatures for the Florida peninsula. The Gulf of Mexico coast has 33 percent to 40 percent chances of a wet winter, while less precipitation than normal is possible in the Pacific Northwest and Great Lakes regions.
Everywhere else, the NOAA isn’t leaning one way or the other. That’s because better indicators of winter weather patterns, known as the North Atlantic Oscillation and Arctic Oscillation, are difficult to forecast more than a matter of weeks out, Halpert said. How they behave will largely govern climate trends, he said.
“The last three winters are a tremendous example of the variability you can see during winter,” Halpert said.
Winter 2011-2012 saw barely any significant snow in Maryland and was the sixth-warmest on record, while winter 2010-2011 saw a below-average 14.4 inches of snow but lower-than-normal temperatures. Winter 2009-2010 was even colder, and snowfall was a record-setting 77 inches.
AccuWeather.com forecasters said last month they are seeing signs of jet stream patterns that bring cold air from the north and moist air from the south to fuel winter storms. That was in part because of El Nino.
This summer, a weak El Nino was forecast as nearly a certainty, with an 80 percent chance of arriving by September or October. But odds have dropped to about 50 percent or lower that El Nino will develop by November or December, according to the U.S. Climate Prediction Center.
The uncertainty of the forecast should only encourage the region to prepare for snow, Halpert said.
“If you don’t prepare, it’s too late if something jumps up at the last minute,” he said.Have a weather question? E-mail me at email@example.com or tweet to @MdWeather.
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