NOAA calls for mild winter but one with big mood swings

Ice forms on the window of a Chicago Transit Authority train while a commuter hustles to board as a winter storm makes its way through several Midwestern states on Feb. 9, 2018. (Charles Rex Arbogast/AP)

October 17

Don’t expect a particularly harsh winter, but a volatile one. That’s the essence of the National Oceanic and Atmospheric Administration’s winter outlook, released Thursday.

The agency is forecasting warmer-than-average temperatures over a large part of the nation, in keeping with recent trends. Winters are warming up because of climate change, and the overwhelming majority of recent years have tended to be mild on balance.

But even with winters trending milder, they have still unleashed brutal cold snaps and blockbuster storms, and there’s no reason this year won’t be different.

The temperature forecast


NOAA winter-temperature outlook.

Most of the nation is favored to be warmer than normal, but “cold weather is anticipated and some areas could still experience a colder-than-average winter,” the outlook said.

Areas least likely to be cold, relative to average, are Alaska and Hawaii, where the outlook highlights high chances for above-average temperatures. Abnormally warm oceans surround both of these states, which have experienced record-breaking temperatures at times since the summer.

Rick Thoman@AlaskaWx

The sea surface temperatures in the Chukchi and Beaufort Seas off the north and northwest coasts of Alaska were, by far, the warmest of record this past summer, due in part to very early sea ice loss. H/T @Climatologist49 @CinderBDT907 @ajatnuvuk @amy_holman

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The Upper Midwest, which endured a brutally cold second half of winter last year, is the only part of the Lower 48 where above-normal temperatures are not favored. Instead, the outlook calls for equal chances of below-, normal and above-normal temperatures.

The precipitation forecast

 


NOAA winter precipitation outlook.

NOAA’s outlook paints a sprawling zone with elevated chances for above-normal precipitation from Montana to the northern Mid-Atlantic. Within this zone, it’s especially likely to be wet in the northern plains and Upper Midwest. These areas also had a very wet second half of winter last year, which led to historic spring and summer flooding, and the situation could repeat next year if this forecast is correct.

Drier-than-normal weather is favored in parts of the Deep South and central California, where NOAA is calling for the onset of drought conditions.

Ocean temperatures are abnormally high off the California coast, forming a zone some scientists have referred to as “the blob.” Although some scientists have attempted to link this warm water with elevated chances for drought in California, Mike Halpert, deputy director of NOAA’s Climate Prediction Center, told reporters Thursday that he’s unconvinced.

The blob “usually doesn’t play a large role in climate outcomes over North America,” he said.

Halpert made clear that NOAA’s forecast for drought in California is based on computer model forecasts, not the high offshore temperatures.

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