REPORTERS NOTEBOOK: WHAT…EXACTLY…IS A POLAR VORTEX?

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What, exactly, is a polar vortex? Every time that I think I am beginning to grasp the weather, a seemingly new term comes along that I have never heard of. Blizzards? Check. Winter Storms? Check. Polar Vortex? What the ____? The polar vortex is a mass of very cold air that hangs around the north and south poles of the Earth. This giant area of frigid air is normally kept in check around the poles by the jet streams, but due to unusual circumstances, it has drifted over the United States. While the US is pummeled by snow, sleet and freezing temperatures, the North pole is slightly warmer than it normally is at this time of year.

The jetstream just shifts enough … [the front] just moves in over the upper Midwest, and it just sits in place, and it allows the cold air to spread over the entire upper Midwest,” according to Todd Heitkamp of the National Weather Service in South Dakota. The polar vortex phenomenon is not a new occurrence. This exact circumstance happened in the 1990s, according to Todd Heitkamp. Additionally, Heitkamp does not like the term ‘polar vortex’, believing it makes the process seem more dire than it really is. It’s not really a phrase I like — it makes it sound a lot worse than what it actually is … This has happened before,” Heitkamp stated. The polar vortex can be dangerous, especially if people are not prepared for the intense cold wind, bringing wind chills of an excess of negative 20 and lower in some areas. In environments of sub zero temperatures, exposed skin can develop frostbite and some cars may not run properly. It is recommended to avoid going outside during the next couple days if at all possible.

 

 

Frank Giannasca, senior meteorologist with The Weather Channel, says it’s an arctic cyclone, it ordinarily spins counterclockwise around the north and south poles. While it tends to dip over northeastern Canada, it’s catching everyone’s attention because it has moved southward over such a large population — as many as 140 million Americans are feeling the freeze. There’s a variety of reasons why a chunk of cold air over Canada would break off our way. Chiefly, warmer air builds up over areas such as Greenland or Alaska, and that air forces the colder, denser air southward. Also, weather patterns can create the right conditions for the polar vortex to point south. But in this case, “this very well just may be one of those anomalies where it forces itself southward,” Giannasca said.

Is this a rare phenomenon? Yes, and no. Through the course of a winter, the arctic air can get displaced southward, typically into the eastern U.S. But it is uncommon for such cold air to cover such a large part of the country, happening maybe once a decade or longer. Amplifying this polar vortex are the extreme cold and brutal winds — sending places such as Fargo, N.D., at 32 below zero and Madison, Wis., at minus 21. Add the wind chill, and it will feel like minus 50s and 60s in some parts.

Could there be a polar vortex of this magnitude again this winter? Forecasts show temperatures around the country as a whole will begin moderating by the end of the week — that means the 20s and 30s in the Plains and Midwest, while parts of the mid-Atlantic and Northeast could be in the 40s. But, like any unpredictable weather phenomenon, whether or not this can happen again, “is hard to say,” Giannasca said.

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Posted January 6, 2014 by dmnewsi in Uncategorized

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