A polar vortex will bring cold temperatures to some 75 percent of the country in the coming days, but the worst of it will hit the Midwest and the Great Lakes regions, which are bracing for brutal, dangerous cold, which will likely break records in many places. The worst of it will arrive on Wednesday, (January 30th), with the National Weather Service saying, “This is the coldest air many of us will have ever experienced,” as temperatures will plunge as low as 40 degrees below zero in some places with wind chills in the minus 50s and even minus 60s. The polar vortex was split into pieces last month by a sudden blast of misplaced warm air, and one of the pieces is bringing the frigid temperatures in the U.S. this week.