Extreme cold in the Midwest and Northeast starting around Tuesday.
Weather maps and forecast models show similarities between the upcoming system and the polar vortex that developed in January 2014, whentemperatures dropped into the single digits in some cities.
Coldest in two decades
The Janurary 2014 system brought some of the coldest weather in two decades to the Midwest, with life-threatening wind chills as low as 60 F below zero (minus 51 C).
Thanks to Gordon Broussard for this link