A major early-season snowstorm is expected Saturday as an area of low pressure tracks up the U.S. East Coast, bringing the possibility of significant snowfall in a broad band ranging from the central Appalachian to the southern New England regions.
Winter storm watches are in effect for parts of the Mid-Atlantic and Northeast regions, including the extreme northern and western suburbs of the Washington metro area.
Total snowfall amounts of 4 to 8 inches are forecast from the higher terrain of Virginia and West Virginia northeastward through eastern Pennsylvania, with a band of 8 to 10 inches possible from extreme northern Maryland northeastward through northern New Jersey and into western Massachusetts, the National Weather Service said in a statement.
The agency also said that lighter snow accumulations are possible for major cities of the Mid-Atlantic and Northeast regions, including Washington, Baltimore, Philadelphia, New York, and Boston.
A surface low with a central pressure of 1,010 millibars (29.83 inches) has developed off the coast of the Carolinas, and it is moving northward at 10-15 mph. Meanwhile, a frontal boundary extended southward from the surface low is crossing southern Georgia into the Gulf of Mexico.
A cold polar air mass has moved into much of the eastern United States behind this frontal boundary. A large area of precipitation covered much of the eastern U.S. from the Carolinas northward to Pennsylvania. Most of this precipitation was falling as rain, with snow falling well inland at higher elevations.
The surface low off the Carolina coast is forecast to move northward to the Delmarva (Delaware, Maryland, Virginia) penisula's coastal waters by early afternoon Saturday and to New England's coastal waters Saturday night. As the low moves northward, colder air will be pulled in behind the system, changing rain to snow at lower elevations from Virginia northward into southern New England.
The National Weather Service noted the precipitation should come to an end across the Mid-Atlantic states by Saturday night and across New England by late Sunday. Additional snowfall amounts of 5 to 10 inches with locally higher amounts are expected across inland areas of the states in the Mid-Atlantic and Northeast regions.