The Tennessee Valley could see some of the heaviest snowfall, with 6 inches expected on Friday. A wide swath of the country is under winter weather warnings and advisories and will see impacts including "widespread closures, treacherous travel, scattered power outages, and downed branches," the weather service said.

Snow and icy conditions threatened to paralyze parts of the U.S. South from Texas to Alabama on Thursday, as officials closed schools, canceled or delayed flights and warned residents in some of the worst-hit areas to stay off roads as a winter storm moves east.

Brutal cold will open the door for a winter storm to take a somewhat unusual track through the South and create treacherous conditions.