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Weather Wednesday: What is the polar vortex?

The popular buzz words can cause fear during the winter months, but is it really as scary as it seems?

KNOXVILLE, Tenn. — Weather Wednesday is about the arctic oscillation – more commonly known by its buzz words “polar vortex." It’s not as scary as it seems – it’s actually a good thing and it’s been around this whole time.

Normally, the polar vortex is cold, arctic air trapped in the poles by the jet stream, a wall of powerful winds. It keeps cold air up north and warm air down south.

But sometimes, strong high pressure will push against the jet stream and cause it to weaken. The polar vortex acts like a bubble – if you push one side, another side is going to pop out.

So, when high pressure pushes north against the bubble, cold air is forced to move further south. This leads to cold temperatures, and sometimes winter weather, for several days at a time.

Normally, we don’t see the true effects of these powerful low-pressure systems in East Tennessee, but when we do, they hit hard. Subzero air and heavy winter weather can wreck our infrastructure simply because we’re not prepared for those kinds of storms. A perfect example: February 2021.

So, while it may sound intense, we actually prefer a strong polar vortex because it keeps the cold air out of the area. It's the weak ones that cause all the trouble. 

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