New Delhi, Jan. 21 -- The National Weather Service (NWS) cautioned early Wednesday that a "dangerously cold Arctic air front" is expected to push single-digit and sub-zero temperatures into the Northern Plains by Thursday, spreading into the Mid-Mississippi Valley, Ohio Valley, and the Northeast by Sunday.

Much of the eastern third of the nation is forecast to see temperatures hovering near or below zero degrees Fahrenheit this week, while wind chills could plunge to as low as minus 50 in some locations, according to NBC News. The NWS warned that frostbite and hypothermia remain a serious risk even when winds are light or calm.

Winter storm warnings have been issued for areas downwind of Lakes Michigan and Ontario as hazardous travel co...