A dramatic blast of cold air may be coming for the United States in late January, courtesy of the polar vortex. Here's what ...

A severe winter storm that brought freezing rain, sleet and snow to a large part of the U.S. was intensified by the polar ...

After this weekend's snow storm moves out, cold Arctic air will move in.

Much of the nation east of the Rocky Mountains is hunkered down for what could be the worst winter storm of the season.

Meteorologists warn that a stretched polar vortex could bring severe winter weather to much of the United States.

Rising Arctic temperatures and melting sea ice could be causing cold air to flow into the Northern Hemisphere. But not all ...

An unusually brutal winter storm is set to pummel more than 160 million Americans from Friday, as a stretched "polar vortex" sends a devastating blast of Arctic air, bringing heavy snows and freezing ...

A polar vortex is expected to bring two surges of extremely cold air to the U.S. in January. Here's what to know in Middle ...

About 230 million people will face temperatures of 20 degrees or colder and about 150 million likely will be hit by snow and ...