An unusual weather pattern driving bitterly cold air from the Arctic Circle south across a huge swath of the US Midwest is expected to send temperatures plummeting from Minneapolis to Louisville, the latest punch from a winter that is in some areas shaping up as one of the coldest on record.
Temperatures will remain in the grips of the deep freeze for 2½ days, said National Weather Service meteorologist Mike Hudson.
It would be similar to what happened earlier this month when temperatures dropped quickly and stayed low for days when a piece of the polar vortex - winds that circulate around the North Pole - "broke off and moved south," Hudson said.
In cities where temperatures spanned from single digits to low teens at the weekend, people will wake up to temperatures well below zero.
And with the wind chill, cities throughout the Midwest will feel far colder than the -20 degrees Celsius that Hudson said was expected in Barrow, Alaska, the nation's northernmost city.
The weather service said city after city will face wind chills well below zero: -41C in Minneapolis, -30C in both Milwaukee and Chicago, -25C in Kansas City, -23C in St Louis, and -19C in Louisville.
In the Chicago area, residents were bracing for a historic deep freeze. The high was expected to be -20C and drop as low as 27 below zero downtown, with wind chills as low as 40 below zero.
Temperatures could remain below zero on Tuesday as well and remain below zero for a total of 60 hours - the longest stretch since temperatures stayed below zero for a record 98 hours in 1983 and the third longest stretch in 80 years.
It also would easily eclipse the 36 straight hours temperatures stayed below zero earlier this month, when the frigid weather prompted the city's public schools to close for two days.
Chicago's school district, which has approximately 400,000 students attending more than 650 schools, said it would be closed on Monday. Districts in the Chicago suburbs also announced they'd be closed Monday.
In Michigan, snow on the roads and deep subfreezing temperatures contributed to multiple crashes that forced expressway closings.
North Dakota and South Dakota residents dealt with dangerous cold and wind gusts that reached up to 96kmh. The high winds led to blowing snow that made it nearly impossible to travel in some areas of the two states.
"This is definitely the most widespread event we've had this year," said meteorologist Adam Jones.
Snow and high winds in Indiana led officials there to restrict vehicle traffic or recommend only essential travel in more than half of the state's counties.