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

When the polar vortex stumbles, the weather at ground level can pivot from mild to brutal in a matter of days. A circulation that usually spins quietly above the pole can suddenly send lobes of Arctic ...

An arctic air mass has descended into the US, and a disrupted polar vortex will keep the nation in the freezer at times deeper into December. More than 200 million people will wake up to freezing ...

As the polar vortex begins to stir, subtle clues point to the coming seasonal shift. So, when will freezing temperatures ...

The polar vortex has broken, and severe temperatures are set to dominate most of the country in the coming days. Temperatures in the 10s are forecast for much of the Northeast, and subzero ...

It's a week into meteorological winter, which began on Dec. 1, and so far there is no mistaking what season it is. The cold air invaded the northeast the last week of November — on Thanksgiving Day, ...

(CNN) — It’s cold now, but the next punch of Arctic air will take it to another level. In the wake of the latest winter storm to sweep across the country, more than 200 million people will wake up to ...