The polar vortex is responsible for this historic cold in the nation today and how it settled over the U.S. has to do with warming Arctic temperatures, suggest NOAA scientists. Temperatures have plummeted in the nation and wind chills in some places in the U.S. are as cold as 70 below zero, according to The Business Insider on Jan. 5.
The spinning winds of the polar vortex of more than 100 mph typically keep the cold weather over the Arctic, but when the temperatures at the Arctic warm, the polar vortex weakens. This causes the polar vortex to break apart and fling parts of this cold dense air over other areas of the globe.
It is a piece of the polar vortex that is covering a large part of the nation today.
A polar vortex is the equivalent of a tropical hurricane in structure. There’s a calm center with winds whipping around the center at great speed. In this case it is not tropical, it is frigid air circling the Arctic with winds of more than 100 mph.
The weakening of the vortex means that conditions are just right for the U.S. to experience this weather pattern that the nation is experiencing today.
This whirlpool of dense and unbearably frigid air descended over parts the U.S. last week. This weather pattern is spreading across the nation and expected to encompass a large part of the U.S. in the next few days.
The nation saw this same weather pattern back in 2009 when parts of the Midwest saw temperatures drop to -22F.