The polar vortex, composed of lofty winds that circulate atop the globe each winter, largely stayed put in the Arctic last year. But in 2021 the winds have weakened, allowing frigid air to spill out of the polar regions. A blast of Arctic air is now destined for a large swath of the U.S. beginning by week’s end.
“The whole Midwest is going to be in the grips of this swaying polar vortex,” said Jeff Weber, a research meteorologist at the University Corporation for Atmospheric Research. “This is air coming straight out of the pole.”
Early next week, many parts of the Midwest will see sub-zero temperatures, and the epicentre of the extreme weather event, Minnesota, will see lows of around -25 degrees Fahrenheit, said Weber.
Monday is predicted to be the coldest day.