"Brace for the Polar Vortex; It May Be Visiting More Often"

"Find your long johns, break out the thick socks and raid the supermarket. After a month of relatively mild winter weather, the Midwest and the East Coast are bracing for what is becoming a seasonal rite of passage: the polar vortex.

The phrase has become synonymous with frigid temperatures that make snowstorms more likely. A blast of arctic air heralded the vortex’s arrival on Monday.

If it seems as if these polar freezes are happening more often, you’re right. “They are definitely becoming more common,” said Jennifer Francis, a senior scientist at the Woods Hole Research Center. “There have been a couple of studies that have documented that.”"

Kendra Pierre-Louis reports for the New York Times January 18, 2019.