An arctic air mass will channel temperatures 20-30 degrees below already historically cold January averages. The South braced for a rare winter storm.

More than 170 million people across the United States, from the Mexican border to the Canadian border are under cold weather alerts ahead of a crippling winter storm expected to sweep through the south from Texas to Georgia,

A Cold Weather Advisory will remain in effect through 9 a.m. Monday morning. The temperature will dip into the teens in many areas, and wind chill values will plummet into the single digits. More sunshine returns for most of the Martin Luther King, Jr. Holiday, but that sunshine won’t provide much warmth, with highs only climbing into the 30s.