The west half of the country, including the Midwest, will start to warm up. But that won't be the case for the East Coast. Here's the forecast.

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

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

A collapse in the polar vortex is letting Artic air come here. What that means, and why it happens.

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 ...

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

This winter, the Northern Hemisphere is suffering from cold waves. In South Korea, an unusually prolonged cold wave has ...

Michigan is experiencing frigid temperatures and heavy snow due to a dip in the jet stream, not the polar vortex. The polar vortex is a large-scale cyclone of cold air that typically stays far north ...