Grab your scarves, don your boots, don't forget your gloves: Old man winter has finally come to the Washington region. Overnight tonight the National Weather Service predicts that dreaded, but oh so familiar, Washington trademark -- the wintry mix, which could impact Friday's morning rush hour.

The Weather Service issued a winter weather advisory{vbar}http://www.nws.noaa.gov/alerts/dc.html for the Washington region in effect from 6 p.m. EST today until 9 a.m. EST Friday morning.

When first issued before dawn this morning, the advisory covered much of today, but as of 1 p.m. the Weather Service said only snow flurries are possible this afternoon and no accumulation is expected.

The bigger problem could come tonight after 6 p.m. EST, the Weather Service predicts.

"The precipitation will likely start as snow," the Weather Service said. "But then mix with freezing rain and sleet during the overnight hours. The heaviest precipitation will occur between 9 p.m. tonight and 6 a.m. Friday morning." The Weather Service said the precipitation will end by mid-morning Friday.

A winter weather advisory means that periods of snow or freezing rain "will cause travel difficulties," the Weather Service explained.

"Be prepared for slippery roads and limited visibilities . . . and use caution when driving," the advisory said. "Allow extra time to reach your destination."

Prince George's County, Charles County, Fauquier County, St. Mary's County and Calvert County Schools canceled all after-school and evening activities today.

The winter storm moving toward Washington dumped a mix of snow, sleet and ice from Georgia north toward this area, closing schools and grounding hundreds of airline flights.

The Weather Service said the storm is expected to dump as much as 5 inches of snow and as much as a half-inch of ice in the Southern states.

Atlanta received about half an inch of freezing rain overnight, news agencies reported. Delta Air Lines Inc., which has its hub in Atlanta, canceled about 400 flights yesterday and early today, although it expected to resume normal service by this afternoon, the agencies said.

Schools and businesses across the region closed or opened late, more than 2,000 homes and businesses lost power in western North Carolina and flights were cancelled in the Carolinas, the Associated Press reported from Raleigh.