The majority of the United States will experience chilling temperatures due to a blast of arctic air from Canada. The Midwest, Mid-Atlantic and Southern U.S. are expected to see below-freezing temperatures due to a polar vortex system.
The Weather Channel forecasts a major winter storm that will drop snow, sleet and ice across the country, from Texas and Oklahoma to the Carolinas.
And it looks as if we may get even more arctic blasts in the coming years. According to a study published in the journal Environmental Research: Climate, outbreaks from the Arctic will continue throughout the Northern Hemisphere in the coming decades despite the region warming faster than the rest of the world.
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Freezing temperatures are expected to move eastward, reaching major cities like Philadelphia, where daytime highs will reach only the low 20s, with “feels like” temperatures in the teens.
How the stratosphere influences Earth’s surface climate
The North Pole is surrounded by a massive circular upper-air weather phenomenon in the Arctic called the polar vortex. It is a typical pattern that tends to contain the coldest weather close to the North Pole and is more pronounced in the winter.
The jet stream typically acts as a barrier to keep the polar vortex contained near the Arctic, but at times, some of the vortex can break off or move south, bringing unusually cold weather to the U.S., Europe and Asia.
The images below show how the influence of climate change from as far away as the mid-latitudes can trigger an outbreak of arctic air over the U.S. weeks to months later.
Polar vortex and jet stream are both extending southward into the US
The National Oceanic and Atmospheric Administration’s Global Forecasting System model predicted the polar vortex would shift south of the tropospheric jet stream over North America, with the stretched polar vortex corresponding to the shift.
Recently, North America was warmed by the strong (but more importantly, circular) polar vortex during the beginning of January, which allowed mild Pacific air to flood much of Canada and the U.S. The polar vortex will relax briefly before the next stretch starting as the last week of January nears.
Beware of winter’s chilling temperatures
As temperatures begin to dip, cold weather significantly increases the risk of frostbite, especially as temperatures drop toward or below freezing.
The National Weather Service uses computer modeling to “provide an accurate, understandable, and useful formula” to calculate wind chill. According to the NWS, the index calculates wind speed at five feet off the ground – the average height of an adult human face – while incorporating “heat transfer theory based on heat loss from the body to its surroundings.”
The wind chill index is a guide to help us understand how dangerous low temperatures and strong winds can cause frostbite. To determine the wind chill temperature on the chart below, locate the relevant wind speed at the top and the outside temperature on the right; you will find wind-chill temperature where they meet:
NOTE: Parts of this story ran on Jan. 21, 2025.
CONTRIBUTING: Doyle Rice/USA TODAY
SOURCE: NOAA, Environmental Research: Climate, National Weather Service and USA TODAY research
