NEW ORLEANS >> Freezing rain and sleet made for a sloppy Christmas morning trek in parts of the nation’s midsection on Tuesday, while residents along the Gulf Coast braced for thunderstorms, high winds and the possibility of tornadoes.

Icy roads already were blamed for a 21-vehicle pileup in Oklahoma, where authorities warned would-be travelers to stay home. Fog blanketed highways, including arteries in the Atlanta area where motorists slowed as a precaution.

A blizzard watch was posted for parts of Indiana and western Kentucky for storms expected to unfold Tuesday amid predictions of up to 4 to 7 inches of snow in coming hours. Much of Oklahoma and Arkansas braced under a winter storm warning of an early mix of rain and sleet forecast to eventually turn to snow.

Some mountainous areas of Arkansas’ Ozark Mountains could get up to 10 inches of snow, which would make travel “very hazardous or impossible” in the northern tier of the state from near whiteout conditions, the National Weather Service said.

Elsewhere, areas of east Texas and Louisiana braced for possible thunderstorms as forecasters eyed a developing storm front expected to spread across the Gulf Coast to the Florida Panhandle.

The holiday may conjure visions of snow and ice, but twisters this time of year are not unheard of. Ten storm systems in the last 50 years have spawned at least one Christmastime tornado with winds of 113 mph or more in the South, said Chris Vaccaro, a National Weather Service spokesman in Washington, via email.

The most lethal were the storms of Dec. 24-26, 1982, when 29 tornadoes in Oklahoma, Missouri, Arkansas, Tennessee and Mississippi killed three people and injured 32; and those of Dec. 24-25, 1964, when two people were killed and about 30 people injured by 14 tornadoes in seven states.

Quarter-sized hail reported early Tuesday in western Louisiana was expected to be just the start of a severe weather threat on the Gulf Coast, said meteorologist Mike Efferson at the weather service office in Slidell, La. Tornado watches were in effect across southeastern Texas and southern Louisiana.

Storms along the Gulf Coast could bring winds up to 70 mph, heavy rain, more large hail and dangerous lightning in Louisiana and Mississippi, Efferson said. Furthermore, warm, most air colliding with a cold front could produce dangerous straight-line winds.

In Mississippi, Gov. Phil Bryant urged residents to have a plan for any severe weather.

“It only takes a few minutes, and it will help everyone have a safe Christmas,” Bryant said.

In Alabama, the director of the Emergency Management Agency, Art Faulkner, said he has briefed both local officials and Gov. Robert Bentley on plans for dealing with a possible outbreak of storms.

No day is good for severe weather, but Faulkner said Christmas adds extra challenges because people are visiting unfamiliar areas and often thinking more of snow than possible twisters.

In California, after a brief reprieve across the northern half of the state on Monday, wet weather was expected to make another appearance on Christmas Day. Flooding and snarled holiday traffic were expected in Southern California.

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Associated Press writer Bob Johnson in Montgomery, Ala., and Ken Miller in Oklahoma City, Okla., contributed to this report.