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Posted at 04:35 PM ET, 01/12/2012

PM Update: Huge changes overnight and Friday; sharply colder, windy, snow?

From near-70 degree warmth (Saturday), snow (Monday), and heavy rain (Wednesday), the swings in weather this week have been huge. And the biggest swing has yet to come. After today’s almost 60 degree highs, temperatures crash late tonight, and a bitter wind holds them steady Friday. What precipitation accompanies the transition?

Through Tonight: Clouds increase and mainly light rain showers become likely between 10 p.m. and 2 a.m. from west to east. The cold front is through the region by 2 a.m., and temperatures should steadily fall from that point.

Rain showers may very briefly transition to snow showers or flurries between 3 a.m. and 6 a.m when the precipitation abruptly shuts off. Chance of seeing flakes are about 10% southeast of D.C. in southern Maryland, 20-30% chance inside beltway, 30-40% north and west of the beltway in Fairfax and Montgomery county, and 40-60% in Loudoun and Frederick county (highest percentages at high elevations).

With temperatures crashing to below freezing between 4 a.m. and 7 a.m., locations that see snow should be careful for slick spots and a possible flash freeze on roads. But because most of the precipitation will end before temperatures crash, the risk of a flash freeze is low except perhaps in the higher elevations of Loudoun and Frederick county.

Friday: Expect partly cloudy skies and very blustery conditions. Temperatures don’t recover much from their morning lows, only rising to 35-40. Don’t be surprised to see a stray snowflake or two as clouds zip by. Winds are the big story, sustained at 15-25 mph and gusting to 40 mph at times. Wind chills will be in the 20s.

See David Streit’s forecast through the weekend. And if you haven’t already, join us on Facebook and follow us on Twitter. For related traffic news, check out Dr. Gridlock.

Plunging temperatures, snow in the Midwest: The cold front to blast through the mid-Atlantic tonight has produced up to 30 degree temperature drops in the Midwest. In Chicago, a winter storm warning is in effect through Friday morning for 4-8 inches of snow accompanied by wind gusts up to 35 mph. Several inches have already accumulated there.

By  |  04:35 PM ET, 01/12/2012

Categories:  Forecasts

 
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