The high-speed polar jet stream typically spins at a height of 5 to 9 miles above the Earth’s surface, in the lower layer of the atmosphere known as the troposphere.

But when the Arctic polar vortex goes through a weaker cycle, the jet stream may also weaken and meander. This can cause the jet stream to sweep further south and bring cold air from the Arctic ...

The polar vortex circles above the Arctic in a higher layer of atmosphere, known as the stratosphere, between 10 to 30 miles above the surface. Like some human neighbors, the polar jet stream and ...