It is becoming likely that a significant snowstorm will impact much of New Jersey and Pennsylvania from west to east on Friday into Saturday.

While a  high pressure system over eastern Canada keeps the northeast cold, and for New England, dry, an area of low pressure will quickly pass through from the Great Lakes into the Mid Atlantic. An area of snow will break out over central Michigan and western Pennsylvania and New York early on Friday and shift south and east, bringing snow into the rest of Pennsylvania and New Jersey from west to east Friday afternoon and Friday night. Most of the accumulating snowfall over Pennsylvania and New Jersey should end early Saturday morning but will continue over central and southern New England into the afternoon. All precipitation tied to this system should exit the coast by Saturday evening.

While northern and central Pennsylvania and New Jersey are expected to see the most snow, a change in the configuration of the cold air mass in front of the storm or a change in the strength of the system would have significant impact on precipitation amounts and types.

On the south side of the system, plain rain will fall; this is most likely over West Virginia, much of Maryland, all of Virginia, and extreme southern Delaware. Between this rain area and the snow region to the north, an icy mix of sleet and freezing rain is expected and there is a possibility of an accumulating glaze of ice there.

Right now, it appears 6″ or so of snow is likely for places like Philadelphia and New York City and adjacent areas in Pennsylvania and New York.  Lighter amounts of snow are expected north of there, with little or no snow expected from this system over central and northern Upstate New York, Vermont, New Hampshire, and Maine, and only lighter amounts over portions of western Connecticut and Massachusetts.

Rain or a wintry mix will keep amounts lower on the south side of the system too; around 3″ is expected in southern New Jersey and northern Delaware, with even less amounts south of there. A light coating of snow may fall in Washington DC and Baltimore, but most of the accumulating snow should be further up the I-95 corridor around Philadelphia and New York.

It is too soon for the National Weather Service to issue any watches or warnings for this storm; that is likely to happen late Christmas Eve or early Christmas Day ahead of the storm’s arrival.