Washington, D.C. – America’s weather map splits in two as December’s second week unfolds — deep winter chills and snow in the East, springlike warmth and record highs out West.
A powerful Arctic front racing out of Canada continues its march across the Northern Plains and Great Lakes, sending temperatures tumbling 30 to 40 degrees in 24 hours. By Friday, highs across North Dakota and central Montana will hover in the single digits, spreading southeast into the Midwest and Ohio Valley by Saturday. The air mass will drive lake-effect snows of up to 10 inches downwind of Lakes Erie and Ontario, whipped by 40 mph gusts.
Further south and east, a narrow snow band tied to a fast-moving storm will drop 2–4 inches from the Ohio Valley to the Appalachians, while freezing rain may glaze portions of the Dakotas and eastern Montana.
Beyond Friday, that same system slides into the northern Mid-Atlantic, where forecasters expect 1–2 inches of snow along the I-95 corridor between Philadelphia and Washington, D.C. — enough to create slick roads and potential travel delays into early Saturday.
Meanwhile, the West is basking under an unseasonably warm ridge, with highs 10–20 degrees above normal from California to the Rockies. Several locations — including Las Vegas, Phoenix, and Salt Lake City — may challenge record highs and warmest overnight lows through the weekend. The exception is California’s Central Valley, where fog and low clouds will keep temperatures notably cooler.
This sharp east-west temperature divide will persist into early next week, setting the stage for another Arctic outbreak poised to expand southward before the holidays.
