(ABC4) — The term polar vortex may sound like something out of a science fiction novel, but it’s a real phenomenon that affects the United States every Winter, though sometimes to a greater degree.
Let’s take a closer look at this meteorological occurrence.
What is a polar vortex?
According to the National Weather Service, a polar vortex is a low pressure mass of swirling cold air that exists around the earth’s north and south poles.
The polar vortex is made up of air circulating in the stratosphere, which is the layer of air that, in polar regions, begins five miles above the ground and extends to 30 miles above the ground. The troposphere, on the other hand, is the layer of air that we live in. It is located between the ground and the stratosphere, climate.gov says.
Recently, the term “polar vortex” has been used to describe weather that occurs in the troposphere. The following pictures show the differences between the two in terms of where they are located.
In the winter, arctic air becomes trapped by very strong winds in a vortex. The air outside of the vortex, including the warmer air from mid-latitudes, cannot enter the vortex to mix with the frigid polar air, keeping it very cold.
During Winter, the jet stream of air that holds the polar vortex together can weaken, the National Weather Service says. When this happens, it expands, bringing cold air south, and with it, uncharacteristically low temperatures and snowy weather.
But, according to tropicaltidbits.com, the polar vortex is being affected by unusually warm temperatures in the arctic.
The Arctic is heating up faster than any other area in the world, and as such, the sea-ice cover is shrinking. In September and December 2020, the Arctic sea-ice cover shrunk to its second-lowest and third-lowest minimum on record for those months, according to the National Snow and Ice Data Center.
Will it affect Utah?
ABC4 reached out to our meteorologist, Erika Martin, about the effects of the polar vortex.
“Polar stratospheric variability results in vortex split or displacement, commonly understood as a “polar vortex event,” she says. “The impending stratospheric polar vortex is due to impact mainly the eastern half of the country, favoring the Midwest and northeast, by the second half of January. Generally, no, the polar vortex does not affect the Intermountain West.”
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