Travelers setting out for the holidays could face trouble, with snow anticipated in the Great Lakes region and rain expected along the country's East Coast.
The National Weather Service predicts Christmas Eve precipitation from Missouri to Michigan, with rain turning into snow in some areas.
Several inches are expected in Illinois, which could cause headaches at Chicago's O'Hare and Midway international airports. Officials there were preparing for potential delays and cancellations, particularly with more people expected to fly this holiday season.
Severe storms in the South on Tuesday killed at least four people, damaged homes, businesses and cars, and knocked out power to thousands. The severe weather led to some delays at Hartsfield-Jackson Atlanta International Airport. But airport spokesman Reese McCranie said a ground stop wasn't expected.
"Our thoughts and prayers are with the families and friends of the four individuals who lost their lives today during the severe weather that pushed through the state," Mississippi Gov. Phil Bryant said in a statement.
Two deaths were confirmed in Jones County, Sheriff Alex Hodge said, noting the victims' mobile home was destroyed by the storm. Another two deaths and 20 injuries were reported in Marion, with "extensive damage to homes and businesses, multiple roads closed and numerous power outages," according to the state's Emergency Management Agency.
Five tornadoes were reported in Mississippi, while tornadoes also struck Georgia and Louisiana.
On the East Coast, which is being soaked by rains accompanied by warmer temperatures, only Philadelphia International Airport was reporting ground delays this morning.
The NWS reported that a "complex storm system over the eastern U.S. is forecast to consolidate into a main surface low that will track northward from the Gulf of Mexico to the Great Lakes by Wednesday night.
"This will create a variety of weather impacts for Christmas travelers on Wednesday. A broad area of steady rain is expected from Florida to New England, with the heaviest rainfall occurring south of the Virginia state line. The Southeast states will also have some strong to severe thunderstorms ahead of the cold front."
As for a white Christmas, "rain is expected to change to snow from Illinois to northern Michigan, with several inches of snow accumulation a possibility."
Out West, the NWS said, "a Pacific storm system is expected to bring widespread snow showers from Washington state to the western High Plains on Thursday, giving many in those areas a white Christmas. The greatest accumulations are expected for the higher mountain ranges of the central and northern Rockies."
With reporting by the Associated Press.