Stratospheric Warming Could Lead to Colder or Milder US Winter

Imagine a giant circle of cold air high up above the North Pole, called the polar vortex.

Sometimes, the air way up high near the pole gets surprisingly warm very quickly.

This is like a sudden fever for the Arctic.

When this happens, it can push the polar vortex around.

If the polar vortex gets pushed south, it can send a blast of super cold air down into the United States, making our winter colder with more snow.

But, if this warming in the sky doesn't push the polar vortex too much, the cold air might stay further north.

Then, our winter would be more like a gentle breeze, with warmer temperatures and less snow.

Scientists are watching this happen now to figure out which kind of winter we'll have.