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.

As the U.S. prepares to take on another bout of cold weather, the term "polar vortex" is getting thrown around. But what is ...

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

The North Pole is surrounded by a massive circular upper-air weather phenomenon in the Arctic called the polar vortex. It is ...

A winter storm descending on the US is expected to deliver heavy snow and ice to more than 150 million people across roughly ...

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

The sudden blast may come as a shock to many Americans after a mostly mild start to winter, but that warmth may be partly ...

Alabama braces for another polar vortex blast bringing well below freezing temperatures. How cold will temperatures get? Here ...

The meteorologists said the polar vortex system is set up due north of Michigan over Canada's Hudson Bay. It's at least ...

Tens of millions of people are in the path of a major winter storm. Federal cuts threaten efforts to understand the causes of such weather.

Temperatures could fall below -20 F across certain parts of North Dakota and Minnesota.