“Polar Vortex” is a weather buzzword you might be hearing a lot of over the next few days. This feature in weather has always been around, but this buzzword has only started being used within the last few years.

The big question: what is this “Polar vortex”? It is an upper-level low pressure located near the poles of the Earth. This low pressure is persistent at both poles within the troposphere and stratosphere. Under this low pressure is a large mass of cold, dense arctic air.

This “Polar Vortex” is making news here in the United States because part of the vortex has pushed its way southward. This cold arctic air is pushing into areas of the Midwest; bringing some of the coldest temperatures and wind chills the area has seen in over 20 years.

Actual temperatures could fall to 20-below-zero in Chicago with feels-like temperatures as cold 50-below-zero. Milwaukee could beat the all-time coldest low of 26-below-zero set back in 1996. The forecast low is 28-below-zero.

No doubt temperatures and wind-chill will be dangerously cold, but how dangerous? Frostbite can happen in as little as 5 to30 minutes when wind chills are this low. People are being told to limit their time outdoors due to the threat; not only frostbite but hypothermia, too. School and workplaces across the Midwest have closed until Wednesday.

Winds are not only causing wind chills; they will also increase lake effect snow. This happens when bitterly cold air quickly moves over the warmer waters of the Great Lakes. Snowfall rates are expected to be an inch an hour for parts of upstate New York.

Good news: it looks like this cold air won’t last long with temperatures rebounding by the end of the week.