Updated 12:05 a.m. ET
Both coasts of the country are dealing with unusual weather this week during an especially challenging time. An estimated 93 million Americans are expected to drive or fly more than 50 miles from home for the holidays.
In the Sierra Mountains, they're dealing with three feet of snow in some spots.
From the possibility of tornados to heavy snowfall, there is great potential for a travel nightmare this holiday season. The fast-moving storm system is expected to have a significant impact on airport travel as it moves east.
Meteorologist Jeff Beradelli of CBS Miami station WFOR-TV said the southern storm system is looking like a classic severe weather setup, with warm, moist air from the Gulf of Mexico colliding with the jet stream to create unstable conditions. We may see howling thunderstorms and numerous, possibly strong tornados on Christmas Day.
The storms could bring strong tornadoes or winds of more than 75 mph, heavy rain, quarter-sized hail and dangerous lightning in Louisiana and Mississippi, the National Weather Service said. The greatest risk is in areas north of Interstates 10 and 12, with the worst storms likely along and southeast of a line from Winnsboro, La., to Jackson and DeKalb, Miss., according to the weather service's Jackson office.
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On the northern side of the system, there's a possibility of a very wide swath of heavy snowfall.
That will be good news on Christmas Day for folks expecting a white Christmas, but this is going to turn into a travel nightmare as the system makes its way up through the Ohio Valley, into the Great Lakes and interior portions of the Northeast. Some places will see one to two feet of snow, especially upstate New York and interior Pennsylvania.
Much of Oklahoma and Arkansas were under a winter storm warning, with freezing rain, sleet and snow expected on Christmas. A blizzard watch is out for western Kentucky. No matter what form it takes, travel Tuesday could be dangerous, meteorologists said.
"We understand that most people will be focusing on the holiday," said Mississippi Gov. Phil Bryant. "Please plan now for how you will receive a severe weather warning, and know where you will go when it is issued. It only takes a few minutes, and it will help everyone have a safe Christmas."
In Alabama, the director of the Emergency Management Agency, Art Faulkner, said he was briefing both local officials and Gov. Robert Bentley on plans for dealing with a possible outbreak.
Forecasters said storms would begin near the Gulf Coast and spread north through the day, bringing with them the chances of storms, particularly in central and southwest Alabama. No day is good for severe weather, but Faulkner said Christmas adds extra challenges because people are visiting unfamiliar areas. Also, people are more tuned in to holiday festivities than their weather radio on a day when thoughts typically turn more toward the possibility of snow than twisters, he said.
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. Flooding and snarled holiday traffic were also expected in Southern California.
Ten storm systems in the last 50 years have spawned at least one Christmastime tornado with winds of 113 mph or more (F-2) in the South, Chris Vaccaro, a National Weather Service spokesman in Washington, said in an 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.
A National Weather Service statement from Jackson, Miss., said the main questions are how far north and west the threat will spread — and whether the storms will be more scattered, resulting in a greater tornado risk, or more in the form of a squall line, resulting in a higher risk of damaging straight-line winds along with embedded tornadoes.
