TEMPERATURES not seen in years are likely to set records in the coming days across the US Midwest, Northeast and South, creating dangerous travel conditions and prompting church and school closures.

A "polar vortex'" will affect more than half of the continental US starting Sunday and into Monday and Tuesday, with wind chill warnings stretching from Montana to Alabama. The vortex is a counterclockwise-rotating pool of cold, dense air, and is behind the startling forecast: 31 below zero Celsius in Fargo, North Dakota, minus 35 C in International Falls, Minnesota, and 26 below C in Indianapolis and Chicago.

The bitterly cold temperatures already pushed into northern states Sunday morning. The National Weather Service reported a temperature of 23 below zero C in Bismarck, North Dakota, and negative 29.5 C at Duluth, Minnesota. At the height of the cold, wind chills may reach 45.5, 51 or even 56.7 below zero C.

"It's just a dangerous cold,'' National Weather Service meteorologist Butch Dye in Missouri said Sunday morning.

Snow preceded the polar air and was expected to fall throughout much of Sunday from Michigan to Kentucky. Forecasts called for up to 30 centimetres in eastern Missouri and parts of central Illinois, several centimeters in western Tennessee, and 2.5 to 7.5 centimeters in Kentucky.

Already, the weather created travel problems Sunday morning. In New York City, a plane from Toronto landed at Kennedy International Airport and then slid into snow on a taxiway. No injuries were reported, but the airport temporarily suspended operations for domestic and international flights because of icy runways.

Mike Duell, with flight-tracking website FlightAware.com, said Saturday to expect delays and flight cancellations because of the cold temperatures.

"For some of them, they run into limitations on the aircraft. They're only certified to take off at temperatures so low so if they get into a particular cold front it can prevent them from being able to legally take off,'' he said. "In a lot of cases, it's just ice.''

In Missouri, the state Department of Transportation warned that most major roadways were snow-covered, it was too cold for rock salt to be very effective and the wind was whipping, causing whiteout conditions.

"If it gets to the point where it's no longer safe, we will consider suspending operations,'' said MoDOT spokeswoman Marie Elliott.

It hasn't been this cold for almost two decades in many parts of the US. Because of that, medical experts are reminding people that frostbite and hypothermia can set in quickly at 26 to 34.4 below zero C, and it's key to be dressed properly for the temperatures.

"A person not properly dressed could die easily in those conditions,'' said National Weather Service meteorologist Scott Truett in St Louis, describing the expected wind chill in Missouri at daybreak Monday.

Southern states are bracing for possible record temperatures, too. Meteorologists in central and north Georgia say temperatures could drop to minus 17 to minus 13 C by Tuesday, accompanied by wind chills as low as 26 degrees below zero C.

Elsewhere, Minnesota has called off school Monday for the entire state - the first such closing in 17 years. Schools were also closed in the Wisconsin cities of Milwaukee and Madison.

Sunday's National Football League playoff game in Green Bay's Lambeau Field could be among one of the coldest ever played: A frigid minus 19 degrees C when the Packers and San Francisco 49ers kick off in the afternoon.

Doctors suggest fans wear at least three layers and drink warm fluids - not alcohol.