Round One: Late this Evening through 7pm Monday:
The forecast through Tuesday is very challenging with a myriad of precipitation types in store for much of the Washington region, mainly along and west of the interstate 95 corridor. The air mass currently in place out ahead of tonight’s storm system is very dry which will allow for surface temperatures to tumble as precipitation begins falling.
A period of accumulating snow is likely to begin late this evening continuing through the overnight along and north of the Interstate 66 corridor in Northern Virginia and the route 50 corridor in central Maryland. The simulated future-cast radar (image above courtesy WxBell) is from the latest high-resolution rapid refresh model (HRRR) showing snow (blue) breaking out late this evening (the image ends at 8am Monday).
Snow will hold on as the predominant precipitation type across the interstate 70 corridor in northern Maryland where two to four inches of accumulation is possible through 7pm Monday.
Central Virginia and southern Maryland may see a very brief period of snow late this evening before a change over to freezing rain by pre-dawn Monday.
Potential Snow, Sleet and Freezing Rain Accumulations through 7pm Monday:
Round Two: 7pm Monday through Noon Tuesday
The forecast models indicate that a second round of Snow, Sleet and Freezing Rain will develop on Monday evening, continuing through the rush hour on Tuesday morning with additional accumulations of snow and ice likely in D.C., Baltimore, and points north and west.
In fact, this second wave of precipitation in combination with a push of cold air from New England may set up the stage for additional significant accumulations of snow and ice. Northern Maryland is prime to pick up to 6″ of snow through Tuesday morning with a quarter-inch (or more) of ice on top of that. The Shenandoah Valley and Panhandle of WV is also prime for significant icing before noon Tuesday.
Winter Storm Warnings may be issued for portions of northern Maryland, Northern Virginia, the Shenandoah Valley and the panhandle of West Virginia for round two of Snow, Sleet and Freezing Rain expected Monday evening through Tuesday noon. Pay close attention to the forecast from the National Weather Service as Winter Weather Advisories may need to be upgraded to Winter Storm Warnings or Ice Storm Warnings for portions of the region on Monday.