Polar Vortex | NASA JPL Explains

The Polar Vortex was in the news the week of January 6. It seemed every paper and TV broadcast headlined it. Sometimes the reports accurately described what is meant by such a creature. More often, it was described as some sort of monster that had emerged from beneath the arctic ice this winter to wreak havoc. And, it might be an effect of the so called global warming phenomenon. Well, it appears the polar vortex is coming back this week.

The facts are less spectacular. The rotating pool of cold air above the polar region in winter is bounded on the southern edge by the polar jet stream. This jet is a fast moving stream of air in the upper atmosphere going west-to-east. It forms a loose loop around the polar region. Several times in the winter, the jet gets less west-to-east and more wavy. At those times, the jet often comes off the Pacific entering British Columbia before diving southeast across the middle of the U.S. A strong low pressure forms over Canada and draws exceptionally cold air south. This large lobe of cold air pours into the mid-west and eastern states. The cold air can flow as far south as the Gulf and Florida. That scenario occurred the week of January 6. It appears it will happen again this week.

MeteoStar Weather Models

The NASA Jet Propulsion Laboratory AIRS Mission scientists published this excellent video which describes exactly the nature and behavior of the Polar Vortex and why it sometimes impacts the United States.

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13 thoughts on “Polar Vortex | NASA JPL Explains

  1. Nice, clear explanation. And yes, here it comes again. January’s a tough month for varnishers. Even when the varnisher can cope, the vanish can’t. I can sand in the cold, but I have to stop varnishing at about 40-45 or the stuff doesn’t set properly. Grrrrrr…..

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    • Thanks. I thought their graphics and explanation were excellent.

      Too bad about the cold and your varnishing work. Maybe after this cold spell, it will start to moderate. Let’s hope so.

      Thanks for your comments.

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  2. Thanks for this clear explanation of the Polar Vortex, Jim. As you mention, this, and other interesting weather events, is often portrayed by the news media as some terrible and unexplainable monster intent on purposefully doing us humans harm.

    I disagree that the facts are less spectacular, the facts are always far more interesting and exciting, at least to me, but I’m guessing the hyped up version generates higher ratings. Shame.

    I’m happy to be riding out this round of polar vortex in the relative warmth of south Texas!

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  3. Speaking of hype, I’ve been surprised in recent years at the overblown (hah!) way newscasters describe snowfalls and the way jurisdictions declare states of emergency when there’s just a foot of snow. I want to say to them: “Hey, all of you up north, it’s winter. You’re supposed to have snow in winter. It’s normal. Get over it.”

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    • Exactly. There’s a guy I follow on facebook called weatherdude. He gets all worked up over those things. He agrees that the hype is bad.

      Our winter this year is colder than normal. But, no big deal so far. We are just patiently waiting for a thaw.

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  4. The comparison between what people worry about (eg Polar Vortex) and what they are truly at risk for (eg anthropogenic climate change) is, unfortunately, an unavoidable artifact of the evolution of our contradictory human minds. I wouldn’t be surprised if it causes our extinction, not too far off into the future. The psychology of the perception of risk is one example of how our decision-making is based more on arbitrary beliefs than factual reality…like how we exaggerate rare flashy risks over common more dangerous ones, or fear risks we can’t control over more dangerous risks we take deliberately. Even worse is how that weakness of I Want to Believe is manipulated by some for gain. It will be interesting to see how it sorts out, but in the meantime, let’s keep supporting science in every way we can. Making it accessible and sensible, like you do, helps!

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