This storm has really come together on the models in the last 12-18 hours. The vort max has just enough of a dig and neutral/negative tilt to pop a surface low and draw some moisture into the disturbance, which is something these past clippers were missing.
There should be some nice snowfall ratios around DC and points north… certainly better than 10:1. Cold air will be moving into the region tonight, and most areas from southern VA northward will be below freezing at the onset of snowfall. Further south into North Carolina, surface temps may be above freezing at the onset of precipitation, which could hurt snow totals. There is still a fair amount of disagreement with what area gets hit with the heaviest snow, with some models highlighting just south and east of D.C. as others track the best snow over the northern suburbs. That will be something that I will try to iron out with my final update tonight in addition to the northern and southern cut-offs for the 1″+ area.