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How cold and wet this winter in the US?

La Niña (or not) is the biggest wildcard in how this year’s winter might shape up. Overall, NOAA’s outlook suggests a relatively cool, wet U.S. North – and warm, dry U.S. South – this winter.

The National Oceanic and Atmospheric Administration (NOAA) released its 2017-18 winter outlook for the United States on October 19. In the video above, Mike Halpert of the Climate Prediction Center – part of the National Weather Service, best known for its United States climate forecasts based on El Niño and La Niña conditions in the tropical Pacific – explains these experts’ projections for temperature, precipitation and drought during the coming winter across the U.S, assuming – as both observations and computer forecasts suggest – La Niña conditions do develop, for the second year in a row.

NOAA called the possibility of another La Niña “the biggest wildcard” in how this year’s winter might shape up. NOAA also pointed out that La Niña has a 55- to 65-percent chance of developing before winter sets in.

Overall, NOAA’s outlook suggests a relatively cooler, wetter winter in the U.S. North and a warmer, drier winter in the U.S. South. It suggests drought is likely to persist in U.S. northern Plains.

In the video, Halpert explains more about what another La Niña would mean, for example, possible greater-than-average snowfall around the Great Lakes and in the northern Rockies, and less-than-average snowfall throughout the mid-Atlantic region.

Other factors that influence winter weather include the Arctic Oscillation, which influences the number of arctic air masses that penetrate into the South and is difficult to predict more than one to two weeks in advance, and the Madden-Julian Oscillation, which can affect the number of heavy rain events along the West Coast.

Watch the video for more details.

Click here for NOAA’s winter weather tips and FAQs

Image via NOAA

Bottom line: Video explanation of NOAA’s winter outlook for 2017-18.

Read more: NOAA forecasters predict cooler, wetter North and warmer, drier South in 2017-18 winter outlook

Deborah Byrd

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