Polar Vortex Hype Has Returned With Arctic Blast on the Way

Sean Breslin
Published: December 13,2016

The term "polar vortex" wasn't born during the winter of 2014, but that's certainly when it became an internet star.
For the last three winters, virtually every forecast that brought cold weather into the United States was met with one question: "Is this the polar vortex?" Now, as the North prepares for multiple rounds of frigid weather, the polar vortex is back in the news.
It's true that the upcoming round of cold weather is associated with the polar vortex, but it's important to note what this phenomenon is, as well as what it isn't.
(MORE: What We Know About the Upcoming Arctic Blasts)

What It Is: An Upper-Atmospheric Area of Low Pressure

This graphic shows how a strong polar vortex is confined to its respective pole. It's clear that the cold air is not being allowed to creep southward.

Our weather takes place in the atmospheric layer known as the troposphere, stretching anywhere from 4 to 12 miles above the ground. One layer above that is the stratosphere, which is where the polar vortex mostly resides.
There are actually two polar vortices – one each at, or around, the North and South Poles. In the respective hemisphere's colder months, increased temperature differences between the mid-latitudes and the poles create a stronger vortex.
But if you're a cold-weather lover, a strong polar vortex actually keeps colder air locked in closer to the pole. In order for the arctic air to surge southward and into the U.S. or Europe, the stratosphere must warm, weakening and elongating the polar vortex.
As weather.com meteorologists Jon Erdman and Linda Lam wrote in a previous article on this topic, if you want the colder air to stay away, root for a strong polar vortex.

What It Is Not: Any Kind of Storm, Nor a Storm System

This diagram shows a weaker polar vortex, with colder air moving down into North America. Sometimes, this cold air can even reach the U.S.

Just because your area is getting hit by a potent winter storm does not mean that the storm itself is the "polar vortex." This phenomenon is a permanent feature of our atmosphere; it doesn't quite behave like a storm system.
In other words, the polar vortex might play some role in helping to push extremely cold air southward in the coming days, but it won't be responsible for spawning a nasty winter storm. Remember, the polar vortex isn't found in the layer of the atmosphere where weather occurs, so while the different layers interact, storm systems aren't formed in the stratosphere.
Additionally, as mentioned earlier, the polar vortex isn't a newcomer to meteorology. This is a phenomenon that scientists have known about since before the Civil War, according to Stu Ostro, senior meteorologist at The Weather Channel.
"Global warming did not create polar vortexes, though the changing climate might be changing the nature of them," Ostro wrote in early 2014. "Nor did humans create the term this week ... it's been an accepted scientific one for at least 75 years."
MORE: Winter Storm Caly