An arctic air mass sprawling across the eastern, central and parts of the western U.S. on Monday will channel temperatures 20-30 degrees below already historically cold January averages and is poised to slam parts of the South with a disruptive winter storm.

Arctic air continues to impact southern Wisconsin with even colder temperatures Tuesday. Wind chills are expected to reach between 30 and 35 below zero, prompting an extreme cold warning from the National Weather Service.