The GFS and ECM are in general agreement on a moderate snow event for the interior Mid-Atlantic to southern New England later Saturday, Saturday night into early Sunday. The GFS indicates maximum amount near or slightly above 4 in. across interior eastern Pennsylvania to parts of interior southern New England (Fig. 1).
The ECM is heavier with 6-8 in. of snow indicated for north-central Connecticut to northeast Massachusetts and 4+ in. across northern Maryland (Fig. 2). The forecast is susceptible to change.
The higher amounts are favored given the nocturnal timing of the event which will allow snow to accumulate more easily. There is no arctic air with this event so freezing rain is not likely. Precipitation mixes at onset in the Mid-Atlantic region trending toward snow at night especially north of Baltimore.
Over achieving cold over fresh snow cover is likely for Sunday morning in the Mid-Atlantic region and New England/northern Mid-Atlantic for Monday morning.
Fig. 1: The midday GFS model snowfall forecast for a late Saturday/early Sunday event in the Northeast U.S.
Fig. 2: The midday ECM model snowfall forecast for a late Saturday/early Sunday event in the Northeast U.S.