In the upper-part of the atmosphere the weekend will feature a wave of energy in the northern stream of the jet and a second disturbance moving along the southern branch. If these systems “phase” together in time, there can be a storm system that can push far enough to the north and east to make an impact on the Mid-Atlantic region. The likely timetable for this potential storm would be Saturday night into Sunday and with borderline cold in place, the precipitation could be a combination of snow and rain. Having said that, there certainly is the chance of accumulating snow late in the weekend; especially, on the northwest side of Route I-95 in the DC-to-Philly-to-NYC corridor…stay tuned on this one.
While temperatures may bounce back and forth over the next 5 days or so in the Mid-Atlantic region, it looks like a more sustained period of colder-than-normal weather will begin around the middle of next week. Early next week, abnormally cold air for this time of year will invade the interior Northwest, Northern Plains, Upper Midwest and the Great Lakes from an air mass dropping southeastward from western Canada. This cold air push will be anchored by very strong Canadian high pressure system that will edge slowly to the south and east next week. The brunt of this cold wave will be centered in this part of the country from Montana to the Great Lakes with places like Chicago likely to experience many days of below zero cold.