Polar vortex!? But what is it?


Normally this time of the year our lows are in the low teens, but when high temperatures begin to fall to the teens and below, talk of a polar vortex begins to circulate. But what exactly is this? Should you be afraid of it?

Not really, the only major impact to daily life will be extreme cold. Cars might have a difficult time starting with cold temperatures.

So, what is the polar vortex?
The polar vortex is simply a upper level low core of very cold temperatures. The term, “Vortex” comes in due to the counterclockwise flow of the air. Usually, these conditions will stay locked in the Northern and Southern Polar regions due to their respective polar jet streams.

Image courtesy of the National Weather Service

Normally, this jet stays strong enough that cold air can push much to it’s South. During the summer months the sharp temperature change from the United States up to Northern Canada keeps the jet stream strong.
During the winter months that gradient fades away and the polar jet begins pushing south. When the jet weakens, it allows for the expansion of the polar vortex. That then brings pockets of unusually cold temperatures to the areas it moves over.

The polar vortex is nothing new, the term was first coined back in 1853!

So, lets talk about the forecast for us.

The polar jet, will become very wavy as it destabilizes a bit this week. A big dip in the jet stream will allow the polar vortex to expand further south. This will drop our temperatures to single digit highs next week and lows in the negative double digits.

Starting Friday the polar vortex will begin to push south. This will bring the initial batch of very cold weather this weekend. By Monday, the jet stream will push North again, “warming” us up for a bit. Another dip in the jet stream will give the polar vortex room to push South again by late next week. This will once again drop highs to the single digits.

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