Msnbc.com staff and news services report:
By 7 a.m. ET temperatures in the Chicago area had fallen as low as 2 degrees below zero with a wind chill of 19 degrees below, The Chicago Tribune reported.
In the Twin Cities, The Star Tribune reported temperatures as frigid as 15 degrees below zero with no additional wind chill at 6:30 a.m. ET.
And a major storm is looming for next week, said Alex Sosnowski, a meteorologist at AccuWeather.com.
The storm was likely to roll across the Midwest and South, hitting the Atlantic Coast on Monday and Tuesday, where it will encounter the frigid air mass, he wrote on AccuWeather.com.
Msnbc.com story: Brrrr! Snow hits Northeast while Midwest freezes