CHICAGO (AP) -- It'll be a white Christmas for the northern Plains and some Western states, but it's likely to cause troublesome travel.
A large swath of the Dakotas is under a blizzard warning Sunday and Monday, with the National Weather Service forecasting heavy snow and strong winds.
To the east, parts of central Minnesota are under an ice storm warning. Snow is also forecast for much of Idaho, Montana, Utah and northeast Colorado.
Forecasters cautioned drivers to keep alternate routes in mind and prepare for possible delays.
Air travel wasn't yet impacted Saturday at the nation's major airports. But snowy conditions Friday in Appleton, Wisconsin, caused the Minnesota Vikings' team plane to slide off a runway.
The Storm Prediction Center cautioned that warm, humid air could cause severe weather in the lower Plains, Arkansas and Oklahoma on Sunday.