A blast of Arctic air is set to cover much of the United States with temperatures below freezing starting on Friday and into next week, impacting millions of Americans in nearly all of the contiguous states.

An arctic blast will send temperatures across the United States plummeting as bitterly cold air that originated in Siberia will arrive from Canada by week’s end, bringing with it dangerously cold wind chills for millions of Americans.

Extreme cold is set to grip much of the country starting this weekend with the return of the polar vortex. Some regions are expected to see temperatures in the negatives early next week. TODAY’s Al Roker tracks the frigid forecast.