AccuWeather reports the combination of lingering arctic air and two merging storms has the potential to spread a large swath of snow, wintry mix and slippery travel from the Midwest to the East at the end of the week.
As with many winter storms, it's complicated.
Essentially the area between I-64 to I-80 in the Midwest to the central Appalachians has the potential for a significant snowfall and the associated travel delays.
The storm scenario is looking colder and slightly farther south than earlier indications. How much snow falls depends on how quickly two storms come together. One storm is coming from western Canada (an Alberta Clipper), and the other is a storm from the southern United States.
A bit of snow and spotty flurries are likely in the swath from Chicago to Detroit or essentially near and north of I-80.
Along the I-64 and I-70 corridors in the Midwest, the storm could bring significant snow in Louisville and Lexington, Ky., Cincinnati and Columbus, Ohio, and Charleston and Morgantown, W.Va.
A wintry mix is likely in southern Kentucky to the mountains of northeastern Tennessee. The wintry mix could dip as far south as Nashville in middle Tennessee.
Farther east, the area from the northern Shenandoah Valley and Washington, D.C., Philadelphia, Atlantic City, N.J., and Dover, Del., lie in a swath where a few inches of snow could fall. In other words, perhaps enough to shovel and plow.
Colder air will have been around for a few days ahead of the late-week storm. As a result, the snow and wintry mix has a greater potential to adhere to paved and concrete surfaces, raising the risk of slippery conditions and travel delays.
Once again, like that of the Midwest, near and north of I-80 in Pennsylvania to the southern tier of New York, odd favor spotty flurries to perhaps a couple of inches of dry, powdery snow.
Farther south, a wedge of cold air could lead to a wintry mix into northwestern North Carolina to a large part of southeastern Virginia and the southern Delmarva Peninsula. This includes the cities of Beckley, W.Va., Charlotte, N.C., Roanoke and Richmond, Va., and Salisbury, Md.
The arctic air is already unleashing locally heavy lake-effect snow even in areas missed by the path of the general storms this week.
A sneaky storm could bring snow showers, even a coating of snow from Washington, D.C., to Baltimore and Philadelphia, Wednesday night into Thursday morning.
Just as the chance that the western Canada and southern U.S. storms may fail to merge, leaving spotty light snow from the Ohio Valley to the East, there is the potential the two late-week storms fully merge.
While the first idea would bring another non-event to the major cities in the form of radar snow and little reaching the ground, the latter would produce a swath of 6- to 12-inch snow over part of the same area.
New York City, New England
The area from New York City through southern and eastern New England is a tough call at this point. This again depends on how quickly the two storms merge and whether or not cold air shoves the storm too far south.
One scenario being radar snow and a spotty light accumulation. The other being an all-out blizzard.
AccuWeather.com will have further updates on the potential for snow as the week progresses.
EDITOR'S NOTE: This story was written by Alex Sosnowski, expert senior meteorologist for AccuWeather.com.