But what exactly is a polar vortex? Well, first off it's not something new. It's a persistent cyclone in the upper levels of the atmosphere that exists at the earth's poles. It strengthens during the winter and once in a while a piece will dip southward causing abnormally cold temps for the U.S.
Secondly, it's not a weather phenomena you can actually see, like a tornado or a thunderstorm. It's just an air mass. So when the national media posts on Facebook saying "Polar vortex as seen from the skies above Chicago." That's simply not true, you can't see it.
So any time it gets very cold during the winter, it usually has to do with the polar vortex. But this is the first time that it's been a widely used phrase and a misused one at that.