This is a classic
Miller A-type storm with the primary storm (surface low pressure center) tracking along the Gulf coast and then up the Atlantic coast. Many of today’s computer models (NAM, GFS, UKMET, and Canadian) all slam the city with heavy snow. Last night’s and today’s European model also forecast heavy precipitation but suggest snow will change to sleet and then rain after several inches of accumulation near the District.
This is one of those storms where small changes in the storm track can lead to huge differences in how much snow falls on the city. A track too far to the east would mean just light precipitation, whereas a track too far west would draw in milder air changing snow to mixed precipitation and rain.
Unfortunately, the models differ enough on the track to make a definitive call on how much snow might accumulate over any specific place around the city almost impossible this early in the game. However, even the warmer westerly (more inland) track favored by the European model would still favor a whopper of a snowstorm for areas from Leesburg, Va. to Frederick, Md and points west.
Any way you slice it, this is shaping up to be a major storm with the snow probably starting Wednesday night before midnight in the southern suburbs and the wee hours of Thursday morning for locations north of the city. Rush hour Thursday morning could be a mess if the snowier models are correct.