The latest forecast models all show a period of moderate to heavy precipitation moving into the Washington Region on Sunday afternoon and continuing through the evening before tapering off just after midnight on Monday. Temperature profiles are modest for snow in the immediate D.C. Area where I would expect at most a coating to one inch.
The northern Shenandoah Valley to Leesburg and Baltimore will likely pick up one to three inches of snow with four to six inches (Winter Storm Warning Criteria = 5″ +) across northern Loudoun county in Northern Virginia northeastward toward the Pennsylvania State line.
Latest Short Range North American Model: Future-Cast Radar Sunday 8am through Monday 4am
Latest Short Range North American Model: Possible Snow Accumulation through 4am Monday
Behind this system the story will be BITTER COLD with Record Low Temperatures, especially in areas that receive snow pack.