(CNN) -- Oh, the weather outside is %#!$.
That's the tune many travelers may be singing this weekend as powerful storms threaten to bring severe thunderstorms and icy conditions to vast parts of the country, just in time for holiday travel.
Flight delays could be possible Saturday in Oklahoma City, Wichita and Kansas City, CNN meteorologist Sean Morris said. Tulsa International Airport in Oklahoma could be forced to close Saturday because of severe icing, he said.
On Sunday, delays are possible in many key air travel hubs and larger markets, including Chicago, Milwaukee, Boston, New York, Philadelphia, Washington, Charlotte and Atlanta, Morris predicted.
The weird weather comes just as the Christmas holiday travel period is set to get started. About 94.5 million Americans are expected to travel at least 50 miles from home during the holiday beginning Saturday, according to AAA.
"I see problems, and definitely no shortage of them," CNN meteorologist Indra Petersons said Friday.
Of greatest concern: a moderate risk of severe thunderstorms that could produce isolated tornadoes in the lower Mississippi Valley, and the threat of icy conditions in the Midwest and Northeast.
While icy conditions were being reported in Kansas, the problems began to spread Friday night, as a front fueled by moisture from the Gulf of Mexico swept across the Lower Mississippi Valley. Up to 5 inches of rain was expected across a broad area from northeast Texas to eastern New York.
Late Friday, the National Weather Service was reporting that heavy rain was possible from the Lower Mississippi Valley to northern New England. It predicted a band of snow from the Central Plains to the Great Lakes and into some of northern Maine. Freezing rain was possible from the southern Plains to the Great Lakes and New England.
Though it had said there only a "slight risk" of severe thunderstorms over parts of the western Gulf Coast and the Lower Mississippi Valley, the service reported Friday evening sighting a tornado near the community of Newman, Mississippi, about 25 miles west of Jackson.
An almost stationary front that extended from the Southern High Plains to New England was expected to drop sometimes heavy rains by Sunday over parts of that swath.
And a band of freezing rain/sleet was predicted from Oklahoma across parts of the Great Lakes into New England. Ice-storm warnings were in effect for most of Oklahoma through Sunday morning, with thunderstorms and freezing rain possible Friday night, according to CNN's Morris. As much as an inch of ice was expected to coat all exposed surfaces, he said, with at least half an inch of ice possible in Oklahoma City and Tulsa.
Widespread power outages were predicted Sunday.
Heavy rains were expected over much of the Ohio River Valley and mid-Mississippi River Valley on Sunday, leading to flooding next week of low-lying farmland along the Ohio and Mississippi Rivers and residential areas located along rivers, creeks and streams.
Severe storms are possible on Sunday, when a cold front is predicted to move across the Mid-Atlantic and Southeast.
The messiness had already begun Friday, when ice on roads and sidewalks in Iowa was blamed for numerous crashes and falls.
And morning icing in Topeka, Kansas, caused several wrecks, CNN affiliate KSNT reported.
Meanwhile, temperatures will continue to rise in the East ahead of the cold front trailing the storms, with New York reaching an unseasonable 67 degrees Sunday and Washington warming to 72 degrees.
CNN's Tom Watkins contributed to this report