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(CNN) -- A major winter storm system was rolling across the southeastern United States early Monday, sending out shocks of snow, freezing rain and sleet, and forcing some airlines to cancel flights.
AirTran Airways canceled 14 flights Sunday, most of them heading into Atlanta, in order to have fewer aircraft on the ground there at the time the storm hits, spokesman Christopher White said. Another 270 flights were canceled for Monday, which represents a majority of the Atlanta-bound flights for the airline.
There will be a handful of arrivals and departures only, White said.
The latest computer models show wintry weather extending from northeast Texas through the Carolinas, bringing freezing temperatures, snow and ice to areas that normally don't see heavy winter precipitation, according to CNN meteorologist Dave Hennen. The northern regions of Mississippi, Alabama, Georgia and the Carolinas should expect heavy snow, while ice storms are expected to affect the southern regions of those states, he said.
Forecasters expect freezing rain to move north in those states, possibly by Monday morning.
Meanwhile, American Airlines reported that 100 flights in and out of Dallas-Fort Worth were canceled. That's about 20% of American's flights. Its American Eagle carrier has canceled 180 flights.
"That sounds ominous, but in the big picture it could be far worse," spokesman Tim Smith said. He added later that the snow was not as bad as was forecast and that Dallas "really dodged a bullet."
Anthony Black, a spokesman for Delta Air Lines, said the airline expects to operate normally in Atlanta until Sunday night, after which some 330 mainline and Delta Connection flights will be canceled.
Nationwide, "we have planned approximately 1,400 Delta and Delta Connection flight cancellations systemwide Monday as the storm is at its peak, approximately 25% of all planned flights for the day," Black said.
Southwest Airlines reported it is running at normal capacity with no major cancellations.
Atlantic Southeast Airlines spokesman Jarek Beem said the storm had forced a number of cancellations, Sunday through Tuesday. He declined to provide a specific number.
Below freezing temperatures through Tuesday could leave trees and power lines across the south with a heavy coating of ice, said Hennen, which could cause numerous long-duration power outages.
Winter storm warnings covered much of the Southeast as the storm system developed Sunday morning in Texas and tracked along the Gulf Coast.
The National Weather Service has issued winter storm warnings for parts of Texas, Arkansas, Louisiana, Tennessee, Mississippi and Alabama. The agency warns that significant snow amounts could make travel difficult and dangerous. Three to eight inches of snow could fall by Monday evening and roads are expected to be hazardous through Monday night, especially secondary roads.
Various winter storm watches have also been put in place by the weather agency, stretching from northeast Texas to the far western corner of Virginia.
In preparation for wintry conditions, governors in Louisiana and Alabama declared states of emergencies, according to the governor's office in Alabama and CNN affiliate KSLA in Baton Rouge.
"We face a serious storm that will have an impact all across Alabama," Gov. Bob Riley said in a statement. He advised motorists to stay the roads.
Georgia Gov. Sonny Perdue similarly issued a state of emergency.
Snow began falling in Atlanta during the evening hours Sunday, and is forecast to accumulate through Monday afternoon. Temperatures at or below freezing are expected to remain in place through Tuesday, keeping roads dangerous and travel difficult, Hennen said.
Parts of Louisiana could get up to an inch of ice, while other states in the region could get between a quarter and a half-inch of ice coating power lines, trees, bridges and roadways, said CNN meteorologist Reynolds Wolf.
In Alabama, Auburn University canceled classes and viewing events for the BCS championship game on Monday night.
Meanwhile, snow moved into the Northeast but the region was spared a repeat of the Christmas blizzard that virtually shut down large cities such as New York and Philadelphia. Emergency management officials were able to quickly recover from the comparably light dusting of snow that began blanketing the region Friday.
CNN's Nick Valencia contributed to this report.