The polar vortex is about to unleash an Arctic chill across much of the U.S. this weekend, leaving football fans shivering in the Midwest and inflicting subzero temperatures on Iowa voters just before the state's caucus begins.

An area of cold air around the north pole, known as the polar vortex because of its counter-clockwise flow, is set to expand and push a frigid blast south. Kansas City, Mo., will drop to -5F Saturday as the hometown Chiefs take on the Miami Dolphins in an NFL wild card playoff game, while Iowa City is expected to fall to -9F.

The freeze marks an abrupt shift from December, when spring-like temperatures enveloped parts of the country. Extreme cold is now expected to boost the demand for fuel to heat homes and businesses, sending natural gas prices soaring the most since July 2022 earlier this week and raising concern about whether power grids will be up to the test.

"It took winter about six weeks to get started, but it's going to go gangbusters for the next couple of weeks," said Rob Carolan, owner of Hometown Forecast Services, which provides outlooks for Bloomberg Radio. "This will be the coldest stretch of winter so far from the Plains to Midwest."

A few pieces of the atmosphere's machinery have come together to bring intense cold across central Canada and the U.S. First, the stratosphere above the north pole warmed a few weeks ago, which disrupted the polar vortex enough to allow it to send arctic air down across Canada, Carolan said.

In North America, the chill is getting supercharged by blocks, or patterns in the atmospheric pressure field that are nearly stationary, across Greenland and eastern Canada that are forcing the polar jet stream south.

"That is having a larger impact than the polar vortex," said Paul Pastelok, a meteorologist with AccuWeather Inc.

There is also snow across parts of the Great Plains and Midwest, which gives the frigid air flowing into the U.S. a boost. All this could mean some deep cold reaching as far south as Texas. The state's grid operator is monitoring conditions due to the risk of higher demand and lower power reserves.

Temperatures in Dallas could hit a low of 15F on Monday and 24F in Houston on Tuesday, according to Maxar Technologies Inc., a commercial forecaster.

East won’t be spared forever

New York and the Northeast won't be as cold and will experience weather whiplash over the weekend. Another powerful rain storm is forecast to swing into Manhattan on Friday and temperatures will rise to near 60F on Saturday as warm winds push north, but by Sunday lows will fall below freezing.

Although the Arctic blast will moderate farther east, the coldest air of the season will also arrive along the East Coast by Tuesday or Wednesday.

Lows may dip to the mid- and upper teens along the Interstate 95 corridor from Virginia to Boston on Wednesday, with interior areas in the single digits or colder. Freezing highs are probable from Washington northward.

Freezing overnight conditions may also dip to northern Florida by Wednesday, with the rest of the Gulf Coast probably sinking into the 20s.

While gas prices have jumped on the outlook for the Arctic chill, the heating oil market has remained muted amid ample stockpiles. East Coast retail prices fell below $4 a gallon in January for the first time in nearly two years.

-- With assistance from Chunzi Xu.