Mild weather during the work week, winter in full force on the weekends.
Forecasters predicted the warm weather in the Northeast would be blown away by gusty winds Friday, to be followed by bitter cold.
But the already-cold northern Plains will get colder, says CBS News meteorologist George Cullen.
"A good part of the country will have temperatures no better than zero today, and that will extend from Wisconsin into Iowa, Nebraska, Wyoming and Montana, and temperatures tonight will bottom out well below zero in over twenty states," Cullen said.
High temperatures Friday in North Dakota, for example, were expected to range from 3 below to 11 below.
The wind chill in Dickinson, N.D., hit 30 below Thursday, but Tracy Tooz and his construction crew kept working on a housing development there.
"It's pretty nasty," Tooz said. "I don't know anybody who likes this polar bear climate."
Forecasters said people who don't take precautions against the cold weather could suffer frostbite or hypothermia.
"Carry a winter survival kit — a shovel, extra food, water, cell phone, and obviously, some extra blankets," North Dakota Highway Patrol Capt. Kyle Kirchmeier said.
"The big thing is when a driver's vehicle breaks down, they should remain with the vehicle," Kirchmeier said. "If they get out and get walking, it doesn't take long to get hypothermia."
An early morning icy glaze, topped with a fluffy layer of snow closed schools and caused some slippery driving Thursday as a winter storm blew across Iowa.
A break in the weather midmorning was expected to give way to a second band of snow across the state, said Gary Forster, a forecaster with the National Weather Service.
"It should bring another inch or two in most areas," he said. "Up north, 5-inch amounts are common. We should end up with 3-4 inch totals here in Des Moines."
The weird weather mix in Wisconsin Thursday included rain, sleet, snow, lightning, thunder and wind gusts to around 50 mph, all in advance of arctic air sending the state into the deep freeze for the weekend.
"It was a great system," said Steve Davis, of the National Weather Service in Sullivan. "For meteorologists, these are extremely interesting."
Snow that some residents described as dark as chocolate brown was reported across parts of Colorado Thursday, a result of a wind storm in northern Arizona that kicked up dust that fell with snow overnight, officials said.
"It's pretty much statewide," said Ethan Greene, director of the Colorado Avalanche Information Center.
Greene said it's not unusual to see plumes of reddish dust from the desert Southwest drop on the Rocky Mountains in the spring.
A cold front may have spawned two tornadoes in Indiana. Some buildings were damaged at the Terre Haute Airport, briefly trapping three people. A church in Terre Haute was also damaged. And as many as ten homes were damaged in Vincennes. No injuries are reported.
The storm knocked out power across much of central and southern Indiana, while strong winds also cut electricity to at least 100,000 homes and business in southern Michigan.
It's quite a change from Thursday, when Tulsa hit 72 degrees and Dallas reached 85.
"Right now, we're looking at temperatures that will be in the teens and 20s across the central and southern plains, areas that were in the 70s and 80s yesterday," Cullen said. "As a matter of fact, it's going to be colder in parts of Kansas and Oklahoma today than it will be up in Fairbanks, Alaska."
The balmy weather midweek melted much of last weekend's record snow in the Northeast, but that's going to end — suddenly.
"Temperatures will drop from the 50s to the 20s within an hour or two," said Cullen.
Despite the record-setting storm in the Northeast last weekend, parts of northern New Hampshire and more than half of Vermont — areas that count on snow for recreation-related businesses — got one-tenth of an inch or less.
"My mother's going to be 85 and she's never seen anything like this," said Martin Beattie, owner of Marty's 1st Stop grocery store and gas station in Danville, Vt., next to major snowmobile trails.
It's the same story in Maine and Vermont for snowmobilers, cross-country skiers and others who depend on snow and ice. Sled dog races have been canceled and ice fishing derbies have been postponed.
At the National Toboggan Championships in Camden, Maine, temperatures that climbed to the mid-40s melted ice on the 400-foot chute and created puddles. Competitors ended their runs with a blast of water, much like a log flume at an amusement park.