Jan. 26 (UPI) -- Wind chills below zero smacked much of the Northern Plains and Upper Midwest on Saturday, and the region is bracing for the coldest outbreak in 20 years.
Nearly a quarter of the U.S. population -- more than 68 million people -- will have temperatures, not including wind chill, fall below zero next week, CNN reported.
The Chicago National Weather Service bluntly posted on Twitter: "There's no mild way of saying it. Brutal cold is coming."
People should "ensure the car, home and your family are ready," NWS Chicago warned.
"Record breaking and potentially historic outbreak of cold still appears to be in the offing for the middle of next week," the service tweeted. "Greater than normal degree of forecast uncertainty in temperatures, due in large part to models showing all-time records being broken and in some cases shattered."
The Midwest is already shivering from a cold front.
At 5:45 a.m., the temperature was minus 2 at Chicago Midway Airport, the weather service reported. During the day, the temperature was in the mid-teens.
And winds made it feel much colder.
On Saturday morning, the wind chill was minus 16 in Chicago and minus 20 in Minneapolis.
Madison, Wis., set a daily record low of 23 degrees below zero on early Saturday -- the coldest morning since Feb. 3, 1996.
Madison's overall coldest temperature in history was 37 below on Jan. 30, 1951, and all-time coldest wind chill of 54.3 below on Jan. 20, 1985, according to the Wisconsin State Journal.
Weather.com reported few daily record lows this weekend will be threatened because the coldest weather east of the Rockies is later in January.
But another round of arctic air will bring widespread subzero temperatures to the Midwest. On Monday, wind chills will dip to minus 20, while it'll feel like minus 30 or minus 40 from Des Moines, Iowa, to Fargo, North Dakota, on Tuesday.
Then, a second widespread blast of arctic air will sweep southward across the Midwest, potentially bringing the coldest air in two decades to parts of the Midwest.
CNN reported 20 cities have the potential to break record lows Wednesday and Thursday morning.
The Twin Cities region of Minnesota is forecast to hit the minus 20s and minus teens in Des Moines, Iowa; Chicago and Detroit. By next week, subzero cold lows may extend through much of the Ohio Valley into the interior Northeast.
The last time it was minus 20 degrees in Chicago was Jan. 18, 1994, and in Des Moines it was on Feb. 4, 1996. Minneapolis, Minn., last dropped to 25 below on Dec. 25, 1996, and Milwaukee, Wis., was last 15 below on Jan. 5, 1999.
Below-freezing temperatures could reach all the way down to Florida.
And strong winds will add to brutal conditions. In a matter of minutes, frostbite could occur on exposed skin.
Wind chill will be in the teens for the major cities in the Northeast on Saturday, ABC News reported.
Heavy snowfall rates of more than 2 inches per hour occurred in Michigan and upstate New York.
The Midwest can expect most snow to fall Sunday night through Monday night.
The heaviest amounts of snow will fall in southern Wisconsin, upstate New York, Vermont, New Hampshire and northern Maine, according to models.