A winter storm watch means there is potential for significant snow, sleet or ice accumulations that may affect travel.
As of early Friday night, snow had fallen in Raleigh; Memphis, Tennessee; Tuscaloosa, Alabama; and the northern Atlanta suburbs.
"The heaviest snowfall (is) expected to fall from the southern Appalachians to southeastern Virginia," the National Weather Service said
, adding that "most precipitation will begin to taper off by Saturday evening."
Georgia Gov. Nathan Deal declared a state of emergency
due to the threat of severe winter weather. CNN meteorologists forecast 3
to 5 inches of snow or more is likely to fall in metro Atlanta. The National Weather Service said
overnight snow and sleet accumulation of 2 to 4 inches was possible in Atlanta.
"This is a very serious weather event," Atlanta Mayor Kasim Reed said at a news conference. "My only concern is that I don't think people have an appreciation for the gravity of it. This is a very, very, significant storm."
Atlanta schools let out two hours early; Georgia state offices closed earlier than normal on a staggered schedule.
Crowds flocked to grocery stores to load up on bread, milk and other items in advance of the winter weather.
Still, others were skeptical. Alex Preston posted a photo of long lines on Instagram. "Because of a snow flurry ... really?" Preston's post said.
Ice might become more of a factor than accumulations of snow in parts of the metropolitan Atlanta area through Saturday afternoon, according to CNN meteorologist Derek Van Dam.
"The ice seems to be having a hard time transitioning into snow," he said.
The best news about the storm is that it will happen on the weekend, which should prevent another "snow jam" scenario such as the one that paralyzed Atlanta in January 2014.
During that storm tens of thousands of weekday commuters left work around the same time, creating massive gridlock on roads and highways and stranding vehicles for hours.
The heaviest snow is expected in the Carolinas, where a winter storm morning is in effect from 7 p.m. Saturday to 1 p.m. Sunday.
Raleigh is likely to face the brunt of the storm, according to the National Weather Service. The North Carolina capital could get up to a foot of snow, making it one of the top five snowstorms in the city's history.
Charlotte may see some 8 inches of snow, CNN meteorologist Chad Myers said.
Gov. Roy Cooper has declared a state of emergency for all 100 counties. The National Guard is ready, and the North Carolina Highway Patrol has been mobilized, Cooper said.
"It looks more and more as if this will be a significant snow event in North Carolina, so we are asking people to stay off the road when this weather event begins, and also to stay off the road when it ends," he said.
Cooper urged residents not to call 911 to ask about weather conditions.
He said his inaugural event, originally scheduled for Saturday morning, had been canceled but a smaller swearing-in ceremony will be held Friday afternoon at the Governor's Mansion.
CNN affiliate WSOC-TV in Charlotte posted images of bread and milk being cleaned off shelves at a grocery store.
Asheville, in the mountains, expected 3-5 inches of snow on Friday, the weather service predicted. The Asheville Airport canceled
all departing flights.
In Birmingham, the storm was expected to begin earlier Friday, most likely as a wintry mix of snow and sleet. There is a chance the air will remain just warm enough in places farther south that the precipitation will fall as sleet.
Gov. Robert Bentley also has declared a state of emergency
-- putting 300 Alabama National Guard soldiers on standby should the storm blow over.
The University of Alabama suspended operations for the day.
Eye on the snow
Hardy folks from the North often scoff at Southerners when they clear out store shelves at the mention of a winter storm, but the practice might have originated in another region of the country, according to AccuWeather.com.
"It appears that New Englanders can take credit for the purchasing of milk and bread prior to the storm," the site reported last year
. "It was the monumental blizzard in 1978 that trapped many in homes for weeks that gets at least some credit for the current tradition."
Amid the run on goods, forecasters are telling people to take warnings and watches seriously.
Major airlines issued advisories about potential impact.
FlightAware, an airline tracking website, listed more than 1,100 cancellations and more than 3,000 delays
as of 8 p.m. ET Friday.
Snowstorms in the South are notoriously difficult to forecast, as timing or a change of 1 or 2 degrees can be the difference between several inches or just a cold rain. National Weather Service meteorologists labeled the storm forecast "tricky" earlier this week.
There is still some uncertainty, as a few forecasting models show precipitation arriving before the temperatures cool down enough to create snow.
There's also a chance that a narrow band of forecasted higher snow totals could widen, producing heavier snow across a broader area.