"WASHINGTON — It might seem counterintuitive, but the dreaded polar vortex is bringing its icy grip to parts of the U.S. thanks to a sudden blast of warm air in the Arctic.

Get used to it. The polar vortex has been wandering more often in recent years.

It all started with misplaced Moroccan heat. Last month, the normally super chilly air temperatures 20 miles above the North Pole rapidly rose by about 125 degrees (70 degrees Celsius), thanks to air flowing in from the south. It’s called “sudden stratospheric warming.”"

Seth Borenstein reports for the Associated Press January 28, 2019. [2]

SEE ALSO:

"Record-Breaking, Life-Threatening Cold Coming To The Midwest After Snowstorm" (CNBC) [3]

"Polar Vortex to Grip Midwest With Most Extreme Cold in a Generation" (New York Times) [4]