Extreme Arctic Cold May Target U.S. in December

The National Weather Service's Climate Prediction Center says the northern and northeastern United States is likely to experience colder-than-normal weather, but some forecasters say a tricky dance involving the polar vortex could send the coldest temperatures on Earth toward the United States.

In an email to USA TODAY, MIT research scientist and climatologist Judah Cohen said, "I believe the cold of the first week of December is the appetizer, and the main course will be in mid-December."

In fact, according to Cohen's computer model—"which I can claim to be the best in the world—it predicts that the largest area experiencing the coldest temperatures on Earth in the third week of December will stretch from the Canadian prairies to the East Coast of the United States."

Snowfall is still a wild card, as snow-producing weather systems typically can't be predicted more than a few days in advance. Suffice it to say, having cold air is half the battle.

Has the polar vortex stopped?

Weather Trader meteorologist Ryan Mau said in a Substack post that the main "polar vortex" load of very cold air will remain over much of Canada for the next 7-10 days. Mau is monitoring the threat of the polar vortex penetrating the Lower 48 by December.

In fact, Cohen said that complex changes in large-scale climate patterns far above our heads—including the infamous polar vortex and a phenomenon called "sudden stratospheric warming"—will determine the intensity and timing of cold weather in the US in December. But he admitted, "I'm confused about what exactly is happening with the polar vortex."

How cold will it be?

Although the coldest temperatures will only arrive in late December, according to the National Weather Service, temperatures below average for this time of year can be expected across much of the country next week, from the western High Plains to the East Coast, with some conditions near average in the southeastern states and warmer in Florida.

A cold disturbance is expected to bring the highest and lowest temperatures across the Midwest on Monday, December 1, and Tuesday, December 2, with highs in many areas only in the 10s and 20s, and lows reaching 0 in northern Missouri and Illinois by Monday morning as an arctic air mass moves into the region.

The weather service said temperatures could drop below zero overnight in some areas from eastern Montana to North Dakota.