A glance at Sunday morning’s weather map shows a very impressive 980mb bomb of a low pressure system off the coast of Maine, nearly making its way onshore in Nova Scotia. It is spreading very heavy snow and blizzard conditions into eastern and northern New England (52 mph wind gust at Nantucket!). A secondary disturbance is tracking through the Great Lakes region early morning. The feature should lose some of its juice as it hits the Appalachian Mountain blade in central Pennsylvania, however some scattered snow showers and flurries have the potential to spread to the Atlantic Coast later Sunday afternoon and evening.
Altogether, expect a day with more clouds than sun with temperatures 10-15 degrees below average. Such has been the trend this month, as Baltimore currently sits at a -3.4 F temperature departure from normal. High pressure will finally — albeit briefly — build into the region late Sunday night and during the day on Monday, bringing a mostly sunny, cold, dry, and somewhat breezy day.
The relatively tranquil weather will be short-lived as a warm front and area of low pressure approaches on Monday night and Tuesday. Fairly stark modeling differences exist between the GFS and ECMWF; GFS shows a fairly quick warm frontal passage with a period of snow Monday night, most gone by Tuesday morning.