An all-out major snowstorm is still on the table in the I-95 corridor from DC-to-Boston for late Friday night and Saturday and this will not be the only serious snow threat that we’ll encounter over the next couple of weeks. In fact, there appear to be multiple snow threats coming during the next couple of weeks and also some serious cold air outbreaks. The early weekend storm will be the type that can produce a foot or more of snow in parts of the I-95 corridor, but there are still some questions that remain at this point and it is still a few days away. For an idea as to how rapidly this storm may intensify and how deep it may become as it treks from the Mid-Atlantic to New England coastline, here are the 24 hour central pressure changes as predicted by the latest European computer model forecast: 1003 mb --> 996 mb --> 984 mb --> 969 mb --> 959 mb (44 millibars in 24 hours; 959 millibars equals 28.30 inches).
In the meantime, today’s “clipper” system has produced on average a 1-3 inch snowfall across DC and its northern and western suburbs. The snow there will taper off later this afternoon from southwest-to-northeast. In Philly, the snow which had been inhibited in its advance by low-level dry air, will intensify somewhat going into the late afternoon and it should continue through much of the evening producing on average a coating to a couple of inches. The NYC metro region will be on the northern fringes of this “clipper” system with little in the way of snow accumulation. One final note, after the snow "lightens" up this evening in the I-95 corridor and the "dynamic cooling" ends in the atmosphere, there is liable to be a period of freezing drizzle which could make roadways quite slick. Quiet weather will close out the work week on Thursday and Friday, but then attention will turn to the east coast for what could turn out to be quite a blockbuster nor’easter.