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Posted at 03:10 PM ET, 12/25/2012

Tracking Wednesday and weekend storms with wet and wintry potential

* Winter Weather Advisory far N/W suburbs Wed-Wed night | Christmas Eve snow totals *

We’re watching two storms that are making for an interesting Christmas-to-New Year’s Day forecast period in the nation’s capital. Neither storm appears to a be a blockbuster, but each could present at least low to moderate impacts locally. The first storm arrives tomorrow, with the next one aiming for Saturday-Saturday night.

Storm #1: Wednesday wintry mix changing to rain

The first storm arrives early Wednesday with a wintry mix of snow, sleet and rain moving in during the early-to-mid morning from southwest to northeast, except mainly rain for Southern Maryland, before changing to all rain for most of the metro area by or during the afternoon. Rain could be moderate to heavy at times during the afternoon into evening, with over 1” of rain possible before tapering by late evening.

Summary of timing and impacts:

* Wintry mix arrives from southwest to northeast around 6-11 a.m. (mainly rain for Southern Md)

* Light snow/sleet accumulation possible (under a half-inch) north and west of Beltway

* Watch for a.m. icing on roads in Carroll, Frederick, Loudoun and northern Fauquier counties

* Precipitation changes to all rain from southeast to northwest from 11 a.m.-3 p.m.; afternoon highs in upper 30s to mid-40s

* Over 1” of rain possible before tapering late evening

Keep reading for more detailed information on tomorrow’s storm as well as the potential weekend storm...

The best chance for snow and sleet is from around I-95 and D.C. toward points north and west. Right now we think precipitation could arrive early enough such that temperatures near or just below freezing could allow for a light accumulation of snow and sleet (less than a half-inch) mainly in the north and west suburbs that are north and west of the Beltway. Accumulation is less likely if precipitation is delayed until later in the morning as one model shows (see graphic below).


Model forecasts for accumulated precipitation from 1 a.m. -7 a.m. Wednesday. GFS (left) shows a wintry mix arriving earlier than NAM (right), which would increase the odds of seeing a light accumulation north and west of the Beltway due to colder temperatures earlier in the day. (StormVistaWxModels)
A Winter Weather Advisory is in effect for Carroll, Frederick, Loudoun and northern Fauquier counties where some icing on roads, especially bridges and overpasses, is possible during the morning. Meanwhile, hazardous travel conditions with up to 4-5” of snow, and near or bit more than 0.25” of ice, is expected in northwest Virginia (including around Winchester), the panhandle of West Virginia (including around Martinsburg), and Western Maryland.

Any accumulation in closer-in areas (Montgomery, Fairfax and Prince William counties) is probably mainly limited to grassy areas, but check conditions if you are going out in the morning.

Precipitation should change to all rain for everyone from southeast to northwest between late morning and mid-afternoon, washing away any earlier accumulation of snow and sleet in the metro area north and west of the Beltway.

Storm #2: Saturday-Saturday Night snow or mix?

The next storm has eyes on the East Coast for Saturday into Saturday night. The latest models (GFS and European) both show a storm tracking from the Gulf of Mexico toward the mid-Atlantic coast, though neither model is simulating a ton of precipitation for the D.C. area as of now.

The most we can say for the time being is that snow or a wintry mix is possible Saturday into Saturday night. And that while it currently looks more like a nuisance storm than a major snowstorm, that could still change, and there are a lot of details to be worked out over the next few days.

By  |  03:10 PM ET, 12/25/2012

 
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