A polar vortex is driving chillingly cold temps in Kentucky. But what exactly is it?
It’s a term you’ve likely heard a lot about in the news of late: the polar vortex.
It might have you thinking of that one scene in “The Day After Tomorrow” of the instantly freezing ice that chases actor Jake Gyllenhaal down the hallway. To the contrary, the polar vortex is a much more normal feature of the atmosphere, and while the term has become more popularized in recent years, it’s nothing new to meteorologists.
“It’s not like it’s that new of a thing. It’s just new to the people who didn’t know,” Brian Neudorff, a meteorologist with the National Weather Service in Louisville, said in an interview Feb. 19. “Kind of like our jargon making its way into the mainstream.”
Bitter cold temperatures are expected across Kentucky the remainder of the week, with a cold weather advisory from the National Weather Service warning of subzero wind chills across much of the state into the morning of Thursday, Feb. 20.
Here what to know about the polar vortex, including a quick breakdown of how it works with insights from the National Weather Service.
What the polar vortex is and isn’t
The polar vortex, as explained by the National Weather Service, is a large area of low pressure and cold air that encircles the Earth’s poles. Even though it’s often framed in the media as a weather anomaly, the polar vortex is a constant feature of the atmosphere that simply weakens in the summer and strengthens in the winter.
The term “vortex” refers to the counter-clockwise flow that locks in cold air at the Earth’s poles, working somewhat like a vacuum cleaner.
During winters in the Northern Hemisphere, the polar vortex expands, sending cold air southward with the jet stream. This happens regularly during the winter in the U.S., and its occurrence is often associated with large outbreaks of Arctic air across the country, according to the National Weather Service.
The polar vortex itself is nothing new, even if you see the term used more frequently. It’s also not confined to the U.S. and can influence weather in parts of Europe and Asia.
Does the polar vortex pose a danger?
Only in the sense that it can send temperatures plummeting in parts of the country that don’t normally experience frigid weather.
When you hear the term “polar vortex,” you shouldn’t be too worried, but you should prepare for colder temperatures. That means checking the forecast, staying weather aware and making sure your home and car cold weather emergency kits are topped up and ready.
Neudorff stresses dressing appropriately, even if you’re only running a quick errand in your car. A sudden breakdown could leave you in a dangerous situation if you’re stranded and only wearing a shirt or light sweatshirt.
“Any kind of prolonged exposure can lead to hypothermia,” Neudorff said. “So make sure you’re dressed.”
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