Some of the coldest air in years is expected to plunge into the High Plains, Midwest and finally the East in the coming days as arctic air dips down into the Lower 48 for a spell.
The mere mention of the term "polar vortex" can set your head spinning (and maybe eyes rolling). It’s got to be clickbait, right? Or maybe someone dreamed up the name for views? Is it a storm? Am I going to be buried in snow?
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As its name implies, the circumpolar vortex is a counterclockwise-spinning (northern hemisphere) swirl of super-cold air in the upper atmosphere that sits atop the North Poles. The term was coined in the mid-1800s, and it can apply to BOTH the stratosphere (6-30 miles up!) and the troposphere, where most of our weather occurs and the jet stream is located.

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They exist year around but shrivel in summer as the hemisphere warms. When things are normal in winter, the two work in synch -- or out of synch -- with occasional outbreaks of cold into the lower latitudes. However, when the stratospheric polar vortex weakens and gets “kicked” off the pole, it reverberates down to the tropospheric polar vortex and causes it to run amuck in the lower latitudes.
This is how we get prolonged periods of snow and cold, and crippling freezes, snow, and ice in the Deep South. It’s important to realize that the term is NOT a storm. It merely sets the stage for wintry weather with its secret sauce: arctic air.


Oddly enough, there is nothing unusual about either polar vortex right now. The stratosphere has a firmly intact vortex spinning around the pole, and the tropospheric polar vortex is doing its own thing. Nothing to see here, right?
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Well, it’s worth noting that the stratospheric polar vortex and the tropospheric polar vortex are sort of in cahoots, and while they aren’t directly swapping air with each other, they’re both in synch (note the blue/green in the images above) and stretching south to allow numbing cold air to spill into Eastern North America at ALL levels of the atmosphere. What’s even stranger is that it’s merely coincidence. No conspiracy, no cloud seeding, no planned effort, just good ol’ fashioned winter, like it used to be.
So, while the headlines will read, “Polar Vortex Assaults the U.S. This Week," or “150 MILLION People in the Path of the Polar Vortex," remember that while it’s true, it’s also not unusual. (And it probably could be less sensational.) The ‘spheres have aligned to bring down the cold, but it only lasts for a few days, and it’s NOT because the atmosphere has gone haywire.