If you’ve ever wondered why winter sometimes flips from mild to brutally cold, the answer might be hiding 20 miles above your head. That’s where a rare atmospheric phenomenon called sudden ...

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 ...

(CNN) — High above the North Pole, in a slice of atmosphere rarely noticed and even less understood, a transformation is underway. Over the next 10 days, changes in the stratosphere will upend weather ...