Polar Vortex: How Will It Impact This Week’s Weather?

Another Blast of the Bitter Cold on the Way for the Week of December 12 through 16

Remember back in 2014 when we had the extreme cold weather and everyone was talking about the Polar Vortex? Well it is back! Sort of…

While last week was our first cold snap of the season across the Sioux Empire, even colder air is set to move in this week, starting early Tuesday morning. A weather phenomenon called sudden stratospheric warming is occurring and that is leading to polar vortex breakdown. Generally the Polar Vortex is high above the Earth’s surface in the upper troposphere and into the stratosphere. The troposphere is the  layer between the Earth’s surface and around 6 miles up, while the stratosphere is the layer of the atmosphere between about 6 and 30 miles above the Earth’s surface. (SEE BELOW)

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When major “sudden stratospheric warming” occurs, the temperature increases by roughly 50 to 70 degrees Fahrenheit in just a few days over the polar stratosphere. As the temperature warms, the Polar Vortex splits into two separate vortices, one moves over parts of northeastern Canada, while the other migrates to Siberia.

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As the low pressure system weakens and moves into norther Canada it also pushes the polar jet stream south into the United States. The polar jet separates the arctic air mass from the milder air mass so as it drops south it allows for that colder air to spill south as well. Since it is a low pressure system, air wraps around it counterclockwise. When situated over Baffin Island in Canada that wind will push air south into the northern United States, leading to a cold snap.

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A wrinkle in our jet stream presents us with a bit of a warm up moving into Friday, but that will bring us our next chance at snow and at this point it looks as though it could be significant. That warm up won’t last long as even colder temperatures are expected as we move into the weekend.

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Air temperatures might stay below zero for the entire weekend in some spots, especially in northern South Dakota, with wind chills near 30° below zero! This is dangerous cold and could lead to frost bite in as little as 20 to 30 minutes so make sure you are wearing layers as well as covering all of your extremities! The cold doesn’t only affect us, it affects your pets as well! If you have pets make sure you limit their time outdoors and keep them warm!

This will not be as strong or to the extreme like the cold blast we experienced back in early 2014, which made the Polar Vortex such a celebrity. However, it will still be dangerous and will still make an impact in our area.

Brandon Spinner
Chief Meteorologist

Copyright 2016: KDLT News