A major cold snap is forecast to push south into the contiguous United States over the Christmas holidays, with regions between North Dakota and Colorado experiencing temperatures 20ºF to 40ºF below normal over Christmas Eve. Conversely, the east coast may see above-seasonal temperatures, with a forecast high of 71ºF in Washington D.C, and 62ºF in New York City on Christmas Day.

"If you’re West of the Mississippi River on Christmas Day, then you may want to ask for coal in your stocking," tweets meteorologist Ryan Maue, with weather.us. "Extreme cold arriving via Polar Express. Off the charts Arctic cold."

A pooling of warm water in the Pacific off of the Alaskan coast is warming the Arctic air, and as that flow moves toward the pole it displaces the cooler air already there, pushing it south. This may result in yet another repeat of the above-freezing conditions experienced in the Arctic, seen over the holiday season in both 2015 and 2016 — On December 30 2015, the north pole was recorded to have been a full degree warmer than Seattle, WA, was at the time.

With the advance of a cold front such as this, the potential for extreme weather also rises: "On the ‘drunk jet stream’ or ‘jet weirding’ scale of climate disruption, the upcoming next 7-10 days will see extremes off the scale," Maue continued on Twitter.