Overview Spring has officially sprung (as of 12:57 PM), but one pattern that we’ve seen consistently this winter may just repeat itself next week - despite the change of seasons. Specifically, there have been numerous short-term stretches of milder weather this winter that have been followed rather dramatically by cold and snow. Sure enough, we have just begun a 3-day stretch of milder weather around here that will last right through Saturday, but then a cold frontal passage late in the day will usher in colder air for the early part of next week. And, as has been the case during much of the winter, this change back to colder-than-normal weather that follows a brief warm spell could again be accompanied by accumulating snow.
Details Following the passage of a cold front on Saturday, temperatures will trend downward on Sunday as colder air moves in from the northwest and there could even be a touch of light snow accompanying the chill down. It’ll turn even colder on Monday with high temperatures likely confined to the 30’s in much of the Mid-Atlantic region which is well-below normal for this time of year. By early Tuesday, copious amounts of moisture will be moving from the Gulf of Mexico towards the Southeast US coastline. At the same time, a vigorous upper-level short wave will be dropping southeastward into the northern U.S. from central Canada. There is reason to believe that this upper-level trough will combine with the Gulf of Mexico moisture to generate explosive development of a developing low pressure system somewhere off the east coast by late Tuesday or Tuesday night. The exact speed and location of this potential rapid intensification of low pressure somewhere off the east coast will determine whether accumulating snow will be a threat in the DC-to-Philly-to-NYC corridor or perhaps farther up the coast in New England or possibly not anywhere in the Northeast US or Mid-Atlantic as there is still a small chance that this could turn out to be a harmless “out-to-sea” event. It is way too early to make this determination as to where this low pressure will track and how quickly it will intensify and uncertainty remains high, but a serious threat does exist for the Mid-Atlantic and Northeast U.S. as there will be plenty of moisture, plenty of cold air, and a very impressive upper-level trough adding fuel to the fire.
[12Z GFS forecast map for 2AM Wednesday; 12Z Euro model forecast is closer to the east coast and even more threatening for the I-95 corridor]