Millions of Americans should prepare for an Arctic blast that will blanket much of the country in below-freezing temperatures over the next several days. Frigid conditions are expected over a large swath of the contiguous U.

By Thursday morning, air temperatures are in the single-digits -- even near zero degrees in far western suburbs -- with wind chill temperatures approaching Cold Weather Advisory criteria, as low as -10 to -15 degrees.

An arctic blast is headed for Chicagoland as temperatures drop and snow showers arrive. Here's the latest forecast.

Noticeably cooler weather moves into the Chicago area Tuesday, followed by a blast of Arctic air and wind chills as low as -20 degrees.