Significant accumulating snow is on the table for this upcoming long duration event in the Mid-Atlantic region from Sunday into Tuesday. It is possible that the DC metro region gets some of its “best” snows (perhaps 3-5 inches) during “phase 1” from Sunday into early Sunday night while Philly and certainly the NYC metro region get their “best” snows during “phase 2” when the coastal storm is the main player. The snow arrives in DC on Sunday morning and – similar to the wintry mix event earlier in the week – the precipitation may find it somewhat difficult for awhile in advancing to the northeast (i.e., towards Philly and NYC) as it battles a dense, dry, cold entrenched Arctic air mass.
As discussed earlier, two unknowns for this storm at this time involve the ultimate strength of the coastal storm and also exactly where will it stall out. Another unknown at this time is how much mixing will take place in the I-95 corridor and the length of this would have an impact accumulation amounts. It seems a good bet that the initial burst of snow on Sunday in the DC metro region will be followed by a period of mixed precipitation by late Sunday afternoon or early Sunday night. There is also a chance of mixing in the immediate Philly and NYC metro regions late Sunday night/early Monday and less chance of mixing in the northern and western suburbs…typical of most winter storms in the Mid-Atlantic region. Stay tuned as more clarity is likely to come over the next couple of days regarding these unknowns in the upcoming long duration winter storm event.
Meteorologist Paul Dorian