Meteorologist explains what is causing the brutal cold conditions

 SULLIVAN - A seemingly new term has popped up to explain why we're experiencing such cold temperatures over the last few days. It's called a polar vortex. Polar because the weather system originated above the North Pole. Vortex is just a word describing a low pressure system. Combine them and you have a polar vortex. The jet stream drives these and all weather systems around the globe. Senior Forecaster Bob McMahon of the National Weather Service in Sullivan says polar vortices are not uncommon around here. This time it's just especially cold. The last time the Milwaukee area felt a polar vortex this cold was back in 1996. The time before that was in 1982. McMahon says polar vortices even happen in the summer.