Snow, sleet and freezing rain predicted to fall throughout the day Thursday could spell delays at Dallas airports.

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.

Nearly 90 million Americans are under winter weather alerts as another high-impact storm is blasting across the nation's midsection, snarling travel with several inches of snow and glazes of freezing rain and sleet.