For Millions, This Might Be the Coldest Christmas in Decades

Something big from the Arctic will sweep into the US in the days before Christmas, and it's not Santa Claus. Forecasters say that thanks to a dip in the jet stream, a huge mass of cold air from the north is making its way south and will bring some areas in the Midwest their coldest Christmas in decades, CNN reports. The federal Weather Prediction Center says this week could see the "coldest air of the season," with a "massive expanse of frigid temperatures from the Northern Rockies/Northern Plains to the Midwest through the middle of the week, and then reaching the Gulf Coast and much of the Eastern US by Friday and into the weekend," per the AP.

"Pretty much everyone, at least east of the Rockies, is going to feel the effects of it in one form or another whether it's rain, snow, wind or colder temperatures," AccuWeather senior meteorologist Adam Douty tells USA Today. Chicago can expect its coldest Christmas since 1996, and cities including Indianapolis and Memphis will probably have their coldest Christmas since 1985, forecasters say. Much of the Midwest will see a white Christmas, and the snow could extend as far south as parts of Tennessee and Oklahoma, but forecasters say the system will bring mostly rain—and possible flooding—to much of the East Coast.

Forecaster are predicting extremely cold weather across the eastern two-thirds of the US, including the Deep South. The system moving the cold air south is "sort of the Polar Express and the cold air can hold on to those characteristics because there’s a lot of snow cover on the ground, even across the north-central United States," Greg Carbin at the federal prediction center tells CNN. People should prepare for a rapid drop in temperatures, forecasters say. "The temperature drop across all of the eastern US is going to be 20 to 30 degrees from one day the next after this storm goes through," Douty says. He says travelers across the US can expect a "big mess" in the days before Christmas, with flight delays and potential road closures. (More winter weather stories.)