NEW YORK (CBSNewYork) — Some areas of the country could be seeing the coldest weather in a generation, brought to us by something called a “polar vortex.” So what is it?

As CBSN New York’s Elise Finch explains, it’s a core of polar air.

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The area of counterclockwise-rotating of cold, dense air, typically piled up at the North Pole, is spreading due to low pressure weakening.

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That brings a bitter blast of polar air wherever it goes, hence a polar vortex.

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The spells can last up to several weeks, until the cold air mass returns to its prior state. In this instance, we are expecting the cold snap to last just a few days. Click here to check the current forecast.

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Wednesday’s dropping temperatures are also going to be complicated by a snow squall: A quick-moving system that brings snow, gusty winds and low visibility. It’s essentially a burst of snow that lasts, typically, less than 30 minutes.