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Posted at 03:52 PM ET, 12/15/2011

Almost certainly no snow Friday night in D.C., maybe flurries Sunday morning


NAM model simulating some light accumulated precipitation south of D.C. as of 4 a.m. Saturday morning. Note the freezing line is well to the west, near I-81. (StormVistaWxModels.com)
There’s been some “chatter” in the weather world about snow in the region Friday night. Admittedly, we bumped our Snow Potential Index to (a still lowly) 1 given the possibility. But, frankly, I don’t see it happening. And it’s actually somewhat more likely we’ll see snow Sunday morning, just flurries though.

There are two problems for getting snow Friday night:

1) The bulk of the moisture is passing to the south
2) Temperatures, while cooling sufficiently at upper levels for a brief period of snow, will be well above freezing at the surface (35+).

Maybe, over the northern neck of Virginia and southern Maryland, where precipition is a bit steadier, the rain mixes with snow before ending with no accumulation. That’s the most I expect.


An upper level disturbance (the orange and red shaded area) streams in from the northwest Sunday morning. (GFS model, valid 7 a.m.) (StormVistaWxModels.com)
By Sunday, the air mass will be sufficiently cold at all levels for any precipitation to fall as snow (though probably not stick). However, the source of any flakes is an upper level disturbance from the northwest, whose moisture is likely to be squeezed out when it crosses over the mountains. If we see flakes, it’s most likely to be leftover flurries - just a 20-30% chance right now (but keep checking for updates)

I’m trying hard to find snow, and just don’t see much promise - whether it’s the short term or the long term.

By  |  03:52 PM ET, 12/15/2011

 
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