High up in the atmosphere above the Arctic, something interesting is going on. The upper levels of the stratosphere, above 35 ...

Arctic air is creating chilly conditions for millions of Americans out shopping on Black Friday, as another shot of even colder air from a disrupted polar vortex is expected to further plunge ...

Colorado has one more brutally cold night — and one more painfully chilly morning — ahead before the mercury begins a swift climb back into the normal range. Much of the high country will remain under ...

In an early sign of the winter weather that's coming, the dreaded polar vortex is making news yet again. The polar vortex is "ramping up from its summer slumber," said meteorologist Judah Cohen in an ...

Cold air originating from the Arctic Ocean was dislodged earlier this week and spilled south across the United States. As a result, wind chills across the Eastern Plains bottomed out around 30 degrees ...

BOULDER, Colo. — The polar vortex that moved in Friday is finally releasing its icy grip on Colorado, but not before leaving us with another night of subzero temperatures. The National Weather Service ...

The snow-covered Peace Monument outside the Capitol on Feb. 12. (Jacquelyn Martin/AP) On the heels of successive winter storms that brought heavy snow and ice to a wide swath of the United States, ...

Harsh weather moved west on Monday as a polar vortex was expected to grip the Rockies and the northern Plains after winter storms pummeled the eastern U.S. over the weekend, killing at least 10 people ...

What is the polar vortex? It’s a wintertime mainstay capable of flooding Canada with some of the world’s coldest air ...