Do pre-winter snowstorms signal a harsh winter?
Tuesday marks the first day of winter, but many people in the United States and Europe have already seen a preview. Can we expect a snowy winter?
Before winter officially arrived this year, severe cold, ice and snowy weather socked much of the United States and Europe, disrupting travel plans and even collapsing the dome on a football stadium in Minneapolis, Minn.Skip to next paragraph
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But do these pre-winter blizzards signal a tough winter ahead? The answer, at least for this year, is no — probably.
The early outbreak of winter weather was caused by an atmospheric pattern in the north Atlantic that pushed Canadian air into the United States, and that shouldn't stick around. But because of lingering uncertainties in winter forecasts, climatologists are quick to hedge their bets.
"There's no particular reason I know of that we'd expect that to continue through the rest of winter, but I can't say it won't either," said Kevin Trenberth, a climatologist with the National Center for Atmospheric Research (NCAR) in Boulder, Colo.
Parts of the country will still have plenty of snow to shovel. The official forecast from the National Weather Service's Climate Prediction Center (CPC), which analyzes climate variations to foretell the coming weather, suggests this year the main influence on winter weather is a strong La Niña phenomenon.
In general, years with a moderate or strong La Niña tend to produce a distinctive set of winter weather patterns, said Bob Henson, a meteorologist with NCAR.
La Niña, the cold-weather flipside of El Niño, brings below-average sea surface temperatures across the equatorial Pacific Ocean. This year's La Niña is strong and could be in play until next April or May, according to the CPC.
The three-month forecast from the CPC predicts above-average temperatures in the southern and central states, and below-average temperatures in the northernmost central and western states. There's a high chance of above-average precipitation — possibly more snow — in the Pacific Northwest, Northern Rockies, Great Lakes and Ohio Valley.