An arctic cold front is moving into the U.S., causing some areas to see wind chills drop to 40 below zero this weekend.

Forecasters call such phenomena "The Siberian Express." They explain it is due to cold air that has been building up in the polar regions of Siberia and Canada.

Now, the jet stream is pushing that cold air to the eastern half of the U.S. Cities are far south as Atlanta could see their temperatures drop into the teens.

A cold front also pushed its way through the northern and central Plains and Upper Midwest Friday. Bitterly cold air followed the front as it moved south and winds increased. Wind chills colder than 50 degrees below zero were reported in North Dakota and Minnesota.

Over the Western U.S., the same system that brought snow and cold temperatures to the northern Plains moved through the northern Rockies.

Light snow showers were seen in Montana and Wyoming. Friday's morning temps in Gunnison, Colo., sank to less than 30 degrees below zero.