The National Weather Service at Sterling VA has issued a Winter Storm Warning for Washington DC and Annapolis MD for 3 to 6 inches of snow. (Technically, a warning should only be issued for a snowfall of five or more inches, so this warning may be "downgraded" to an advisory in all areas.) The warning is effective from 7 p.m. this evening through 2 p.m. on Monday. The National Weather Service has issued a Winter Weather Advisory for Baltimore for 2 to 4 inches of snow, effective from 7 p.m. this evening through 2 p.m. on Monday. Rain will change to snow this evening with the heaviest snow falling from midnight through 6 a.m. During this time, temperatures will fall into the 20s and roads may become snow-covered, although roads will turn wet during the morning with the impact of the high March sun angle and temperatures inching closer to 32 degrees.
Various features on the national weather will converge to produce snow in these same areas on Sunday night and Monday. The first feature is another shot of arctic air that will surge southeast into the Mid-Atlantic region by Sunday night. Yesterday's highs in the upper 60s to near 70 have dropped into the upper 30s this morning. Highs will only reach 40 to the lower 40 this afternoon with dew point values in the lower to middle 20s, an indication of the dry air in place. This cold, dry air on a north wind will set the stage for overrunning precipitation to develop on Sunday in the form of rain showers as afternoon temperatures will be in the lower 40s. At the same time, an area of low pressure is expected to develop to the southwest and move across North Carolina on Sunday night and off Cape Hatteras NC on Monday. As the center of low pressure intensifies, colder air will be drawn into the system and will change rain to snow across the region by late Sunday night. Snow may continue into Monday morning, perhaps mixing with or changing to rain on Monday in Virginia. Precipitation will taper to flurries on Monday afternoon.
Here are some links with additional information on the storm:
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