Severe winter weather that hit parts of the central and southern US on Christmas Day has moved east, causing flight delays and dangerous road conditions for holiday travellers.

Some flights headed for New York, Philadelphia and Newark, New Jersey, experienced delays averaging one to four hours due to the inclement weather.

About 1,300 US flights were cancelled today with several airlines waiving ticket change fees for affected customers.

The National Weather Service issued blizzard and winter storm warnings in Illinois, Indiana and Ohio, as well as much of the Northeast.

It cautioned that the wintry weather would create "treacherous" driving conditions.

More than six inches of snow might fall in those regions, while the area from western New York up into central Maine could get from 12 to 18 inches, the NWS said.

Severe thunderstorms and widespread rain were expected from southeast Virginia to Florida, the NWS said, and the eastern counties in North Carolina and South Carolina were under tornado watches or warnings for much of the day.

Twisters struck in Alabama, Mississippi, Texas and Louisiana, flattening houses and causing injuries, according to the weather service.

The storm also dumped record snowfalls in North Texas and Arkansas.

Nearly 200,000 homes and businesses remained without electricity in Arkansas and Alabama today.