The atmosphere is setting us up for quite a nasty situation throughout the entire Mid-Atlantic region from DC to Philly to New York City for later tonight and tomorrow morning with accumulating snow, accumulating ice and dangerous travel conditions. The perfect setup for frozen precipitation has developed here with fresh, very cold and dry Arctic air now in place as moisture streams eastward from the Midwest. Additionally, this Arctic air will be anchored for the duration of the upcoming event by a strong high pressure system headed to our north. The picture looks like this for the following specific Mid-Atlantic locations:
1) DC region: 1-3 inches of snow beginning just before midnight that will mix with sleet and freezing rain later tonight. That wintry mix will continue well into tomorrow with a significant ice build-up in many locations around the DC metro region; especially, in the northern suburbs. It is likely that the precipitation winds down during the afternoon as “above-freezing", "plain” rain in the District and to points south and east, but temperatures will struggle to rise above freezing in the far northern suburbs.
2) Philly region: 2-5 inches of snow that develops around or shortly after midnight and then continues for much of the night (the highest amounts in the northern suburbs). The snow will likely mix with sleet and freezing rain tomorrow morning with an icy buildup on top of the snow. Temperatures will probably hold at or below freezing in the northern and western suburbs during the afternoon as the precipitation winds down, but they could rise above freezing in the city and to points south and east.
3) NYC region: 3-6 inches of snow that develops around or shortly after midnight and continues well into tomorrow. There is a chance that some sleet and freezing rain mixes in for good measure just to add a layer of ice, but this event will be predominately snow in the NYC metro region. Precipitation winds down during the afternoon with temperatures likely holding near or below freezing.