UPDATE VI: Current AccuWeather Radar for the Middle Atlantic States here. The map above depicts 15″ snow forecasts in red with the redish-gray within a forecast of more than 18″. Note this extends into New York-Hartford and almost to Boston.
UPDATE VII: From the National Weather Service:
...RECORD BREAKING DECEMBER SNOWFALL FOR BALTIMORE-WASHINGTON
METROPOLITAN AREAS BRINGING HAZARDOUS WINTER WEATHER TO THE REGION
OVERNIGHT AND SATURDAY...
TOTAL STORM SNOWFALL TOTALS OF 1 TO 2 FEET ARE FORECAST TO OCCUR
IN THE BALTIMORE-WASHINGTON METROPOLITAN AREAS BY DAWN SUNDAY...WHICH
SHOULD ECLIPSE THE DECEMBER RECORDS FOR BOTH CITIES. THE RECORD
DECEMBER SNOWFALL FOR WASHINGTON IS 12.0 INCHES ON 18-19 DECEMBER
1932...AND FOR BALTIMORE TO RECORD IS 14.1 INCHES ON 12-13 DECEMBER 1960
Finally, flooding is an increasing problem in southeast Louisiana, southern Mississippi and Alabama, and the Florida Panhandle.