Temperatures will plunge into the single digits by early Sunday, and likely won't rise above the single digits until Wednesday.

Chicagoland residents are waking up to frigid temperatures early Sunday morning, as the area enters a deep, deep freeze for the first part of the week. So be prepared for bitter cold and dangerously low wind-chill values well below zero.

A piece of the polar vortex spills into the Midwest, creating extreme cold for the Chicago area and northwest Indiana for the next few days. For Sunday morning, actual air temperatures will peak early and fall throughout the day.