There is still a lot of uncertainty with a storm system that is expected to impact the Mid-Atlantic this Thursday, but there is now enough model support to think of the storm as a legitimate threat.
It is hard to determine where the rain/snow line is going to be at this point… I will try to get an initial snowfall forecast out tomorrow, but if forecast confidence is still very low at that point I might wait until Tuesday. Biggest area of concern is northern VA and areas north of DC, where both the Euro and GFS have snow potential.
The 06z GFS forecast for Thursday (108hr) shows potential for a heavy, wet snow just northwest of DC near IAD:
The upper-level vort. max and vertical velocities with this system support snow for some areas as well. Right now it looks like all rain in southern VA, but that could change. This threat has been borderline for the region for days now, but it’s looking good for snowfall potential SOMEWHERE in the region.