Arctic air is back over the Northern Tier of the US and ready to be drawn south into the Northeast with the passing of low pressure. The first low was an all out warm, wet system but the middle week system is quite different. Rain initially perhaps from Philly down to DC but a changeover to snow is expected with 3 inches possible in Philly, maybe a slushy inch in DC but from NYC to Boston, we could see a foot.

Firstly, it’s all about the warmth. Near 70F in DC, 60 in NYC to freezing or below.

Surface/precip

GFS meteograms for Boston, NYC, Philly and DC.