7:45 AM | *****Heavy snow on the way with significant accumulations before a changeover to a period of ice*****

[Latest NEXRAD radar image with moisture in western sections of the Mid-Atlantic; courtesy University of Wisconsin]

Discussion

Skies remained clear for much of the night in the Mid-Atlantic region which allowed temperatures to fall to record levels in some areas. In fact, temperatures plunged to an amazing 6 degrees below zero this morning in Atlantic City, NJ breaking the record there and making this the latest date ever with sub-zero conditions. Records were also set this morning in Allentown, PA, Wilmington, DE and Trenton, NJ.

Meanwhile, those early morning partly cloudy can be deceiving…a mountain of moisture (see radar) is moving quickly from southwest-to-northeast right towards the I-95 corridor and - given these extremely cold temperatures - that spells trouble. Snow will arrive in the DC metro region during the mid-to-late morning hours, in Philly during the mid-day hours, and in NYC during the late afternoon hours. The snow will fall heavily shortly after its arrival with quick accumulations and rapid deterioration in road conditions. The snow will ultimately change to a period of icing (sleet, freezing rain) after significant accumulations and this will add a layer of ice on top of the snow. Towards the latter stages of this storm, areas in the immediate I-95 corridor and points to the south and east of there may actually change to plain rain with above freezing temperatures, but the plain rain and “milder” weather will not be major factor in this upcoming event – frozen precipitation-type (i.e., snow, sleet, freezing rain) will dominate with a thumping of accumulating snow at the onset. In some of the farther N and W suburbs, temperatures will probably not even make it above the freezing mark throughout this precipitation event. Precipitation winds down early Sunday and another brutally cold Arctic blast will arrive on Monday - we'll be flirting with 0 degrees once again by the time Tuesday morning rolls around.

Snow accumulations will generally be higher the farther north and west one goes away from the big cities along I-95. As a result, here are the latest snowfall estimates which will take place before the changeover:

DC: 4-8 in an around the immediate District region; 6-10 inches in the northern and western suburbs

Philly: 3-6 inches in and around the immediate Philly metro region; 4-8 inches in the northern and western suburbs

NYC: 3-6 inches in and around the immediate NYC metro region; 4-8 inches in the northern and western suburbs