The following is via Accuweather.com:

A major snowstorm will hit areas from Philadelphia to Boston with heavy snow and wind and could immobilize areas from near Washington, D.C., to the southern Appalachians with blizzard conditions by the weekend.

The storm will bring significant snow to more than 50 million people and could bring travel to a standstill in part of the mid-Atlantic states.

As the storm strengthens, winds will increase as snowfall rates ramp up. An all-out blizzard will unfold in some areas. Whiteout conditions will occur in several states. The storm is likely to shut down some highways and could cause some airports to close.

Heaviest snow may shut down travel

The swath that could receive 6 inches of snow or more from the storm is expected to extend along a 1,000-mile path from near the Mississippi River to Cape Cod, Massachusetts.
The storm will begin in parts of the South and the Ohio Valley on Friday and will expand slowly northeastward over the mid-Atlantic and southern New England during Friday night and Saturday, before exiting southeastern New England on Sunday.

The metro areas from Philadelphia and New York City to Hartford, Connecticut, Providence, Rhode Island, and Boston will be in the zone where enough snow will fall to shovel and plow. Localized snowfall in this zone can approach a foot. More snow and blizzard conditions are possible should the storm take a slightly more northward track.

Within this zone, the clinging nature of the snow can bring down tree limbs and cause sporadic power outages. The greatest risk of more widespread power outages will be near the coast, where winds will be the strongest and snow the wettest.

Accumulations around the Washington, D.C., and Baltimore areas will average 12-18 inches with the potential for more, depending upon the track and speed of the storm.

The worst conditions will be from southwestern Virginia and the West Virginia mountains to northern Maryland and parts of south-central and southeastern Pennsylvania, where a blizzard is in store. A general 1-2 feet of snow will fall with accumulations in localized areas between 2 and 3 feet. Increasing winds will cause extensive blowing and drifting snow.

“Crews may not be able to keep up with the storm in portions of Virginia, Maryland and West Virginia,” AccuWeather Senior Meteorologist Henry Margusity said. “Some communities could be isolated for a few days.”

Travel could be stopped along portions of interstates 64, 66, 68, 77, 70, 81, 83 and 95 at the height of the storm.

The heavy snow with the storm is likely to have a fairly sharp northern edge due to dry air. At this time, the northern edge is most likely to extend from southern Ohio to southern New England. A distance of less than 50 miles could bring snowfall ranging from an inch or less to more than a foot.

In advance of the storm, Delta Air Lines announced travel waivers for flights through Jan. 24 at 19 different airports in the Northeast and mid-Atlantic region.

Wintry mix could make roads slick

According to AccuWeather Meteorologist Ed Vallee, “Warmer-than-average temperatures in the Atlantic Ocean will factor into the storm near the coast to perhaps as far west at I-95 in the mid-Atlantic.”

For this reason and the potential for dry air to be drawn into part of the storm, accumulations will likely be held to under a foot in most areas from central North Carolina and southeastern Virginia to northern Delaware, much of New Jersey, Long Island and Cape Cod.

For areas receiving a mixture of snow, ice and rain, this will still be a formidable winter storm. Power outages are likely. Travel will be difficult, if not dangerous, as roads become slippery or where poor drainage area flooding occurs.

Winds, coastal impacts and long-duration storm conditions are in store

Winds will become a factor in the storm, causing extensive blowing and drifting snow.

According to AccuWeather Chief Meteorologist Elliot Abrams, “This could be a long-duration snowfall that could last 24 hours or more in some locations.”

Areas where this is most likely to occur is from northwestern Virginia and part of West Virginia to southeastern Pennsylvania.

Since the storm will strengthen rapidly, reduce its forward speed and tap plenty of moisture from the Gulf of Mexico and the Atlantic Ocean on its path, snowfall rates of 1-3 inches per hour are possible. Hence the potential for people to get stranded on the road.

Thunder and lightning could accompany the heavy snow in some locations.

Along the mid-Atlantic and New England coast, a period of rough seas, coastal flooding and beach erosion can occur.