Snow is spreading over the Carolinas and Mid-Atlantic this evening after producing damaging ice from freezing rain in Arkansas and Tennessee last night. Snow will change to ice in North and South Carolina tonight, while areas farther north could see up to ten inches of snow. Here's what to expect.

Tonight's forecast remains largely unchanged from those issued yesterday, with a fine line between snow, sleet, and freezing rain setting up across North Carolina. The rough delineation between snow and ice seems to be the I-40/85 corridor, with those north of the interstate seeing mostly snow and some sleet, while those south of the highway see mostly sleet and freezing rain.

Farther north, Virginia will see the brunt of tonight's snow, with ten or more inches possible in some areas between Richmond and Washington D.C. The capital itself could see up to eight inches of snow, with accumulations growing smaller in Maryland and Pennsylvania.

Snow Accumulations

Here's the latest snowfall map from the National Weather Service, valid around 5:00 PM EST. Accumulations include sleet (ice pellets) in some spots, but sleet tends to keep down snow accumulations through compaction. Any ice that mixes in will increase the chances of the snow/sleet mixture freezing into a solid sheet of ice, which will be very hard to remove from the ground and vehicles once it has a chance to harden.

The NWS predicts the heaviest snow falling in the Appalachian Mountains, with a stripe of eight to ten inches across central Virginia from Roanoke to Richmond and east through the Delmarva Peninsula. Much lighter totals will occur in North Carolina, with a sharp cutoff between six inches and three inches near the border between Virginia and Richmond.

Snow will fall up and down the I-95 corridor tonight, with the heaviest powder falling on D.C. and accumulations going down inch by inch up the highway in Baltimore, Philadelphia, and eventually New York City and Boston. The latter two cities could see about three inches of snow from this storm.

The Vane's nerdquarters near Greensboro, North Carolina, already has about an inch of snow on the ground, and it's coming down pretty heavily as I write this.

Ice Accretion

Ice from freezing rain will be a major issue with this storm, much as it was out west towards Memphis and Little Rock. Between one-quarter and one-half of an inch of ice accretion is possible in southern and central North Carolina overnight tonight and through the early morning hours on Tuesday. Some towns between Raleigh and Fayetteville could see more than one-half of an inch of ice.

One-quarter of an inch of ice is enough to cause tree damage and power outages, and any additional ice accretion will add weight to trees and power lines, making them more unstable and prone to breaking. Even a thin glaze of ice is dangerous on roads and sidewalks, and as many of the areas experiencing freezing rain will likely see a quick burst of snow at the end of the storm, surfaces that just look snow-covered will be solid ice underneath. Try not to drive during the storm if possible, and if you have to walk outside, be very careful and walk with a flat foot to more evenly distribute your weight.

Stay Home...If You Can

Most school systems across the region have already cancelled classes on Tuesday, and it would be a great day to take a personal leave day (if you're fortunate enough to have them) and stay away from the inevitably ugly commute.

The bad news is that many areas will briefly lurch above freezing during the day on Tuesday, allowing just enough of this snow and ice to melt to become a major problem once the next Arctic blast moves into place on Wednesday morning. Temperatures will dip down to (or below) zero as far south as Charlotte and Greenville on Wednesday and Thursday night, so any remaining snow/ice on the ground will freeze into a glacial sheet until temperatures rebound this weekend.

[Images: NASA, Intellicast, NWS]

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