US winter forecast: wetter and warmer, with snow shifting south

Winter across the United States is likely to be wetter and warmer than normal, though not necessarily snowier, according to the federal government's seasonal outlook and other meteorologists' forecasts. The National Oceanic and Atmospheric Administration (Noaa) presented its three-month winter outlook in a media briefing on Thursday, pointing to a strong El Niño as the main driver.

El Niño — a natural but temporary warming in parts of the Pacific that generally heats the globe — is expected to shift weather patterns toward more moisture and higher temperatures. Forecasters expect the current El Niño to reach record levels this fall or winter. Noaa said the pattern should help ease persistent western drought.

Snow shifts south

Noaa's meteorologists said much of the northern US — including the north-east, the Great Lakes, the upper midwest and the northern Rockies — should expect below-normal snowfall, while the southern Rockies, parts of the south-east and the south-west may get more than usual. The weather service does not issue seasonal snowfall totals.

Private forecasts agree. AccuWeather expects Salt Lake City to be the only major metro area with above-normal winter snow, while Chicago, Boston, New York and Philadelphia are forecast to receive about half or less of their normal amounts. The Weather Company's James Belanger said northern snow-lovers may struggle: "This is going to be a winter that's really difficult for them to find what they're looking for."

National Weather Service director Ken Graham cautioned that a milder outlook does not remove the risk of snowstorms. AccuWeather's Paul Pastelok said it "only takes one storm to flip the script", especially for east coast cities, urging a watch for eastern snowstorms in late January and February.

Warmer almost everywhere

Parts of 41 of the lower 48 states are forecast to be warmer than normal, with no states, or parts of states, forecast to be cooler than average. Florida, Louisiana, southern Georgia, Alabama and Mississippi are expected to be near normal, while Texas, New Mexico, Arizona, Utah, southern California, Nevada, Wyoming, western Oklahoma, Kansas and Nebraska have equal chances of warm, cold or normal conditions. Polar vortex outbreaks are expected to be less frequent than in most winters, though not ruled out.

Noaa is also forecasting a wetter-than-usual winter in parts of 39 states, with much of Montana and parts of Oregon, Idaho, Wisconsin and Michigan drier. National Weather Service meteorologist and branch chief Jon Gottschalck said drought conditions are expected to improve or end in western Oregon and western Washington, the south-west, the central and southern Rockies, the southern Great Plains, the lower Mississippi valley and parts of the east. He added that Florida and parts of the south-east should be on guard for more tornadoes this winter and in early spring because of El Niño.

The Weather Channel's Mike Bettes said California should anticipate numerous high-impact atmospheric rivers that could bring extensive flooding and landslides.

Noaa says US winters have warmed about 4F (2.2C) over the past 50 years, predominantly because of the human-caused climate crisis. MIT research scientist Judah Cohen, who is waiting before issuing his own forecast, said an unprecedented El Niño is a reason to be less confident, not more: "We have no real historical analogue or precedent."

Source: The Guardian.