GFS model simulates a piece of the polar vortex infiltrating the U.S. early next week (WeatherBell.com)
Is or isn’t the polar vortex behind the wave of Arctic air slamming into the Lower 48 this week? Depending on what meteorologists you ask, you’ll get a different answer.
AccuWeather says yes – this week’s cold snap is a manifestation of a southward sinking polar vortex. The Weather Channel, showing unusual restraint, has laid off the polar vortex Kool-aid.
Dan Satterfield, a meteorologist in Salisbury, says just stop it already in an appeal to media hyping the polar vortex.
So who’s right? To be sure, the polar vortex is involved in this week’s cold snap – like it is in most cold snaps involving Arctic air. But this is not one of the more rare, high impact cases in which a huge chunk of the vortex breaks off and charges towards the U.S.-Canadian border bringing exceptional cold.
My view is that, to guard against overuse of the term, we should reserve calling special attention to the vortex to those cases in which its behavior is extreme.
As a reminder, the polar vortex is an area of low pressure at high altitudes meandering around the North Pole. When it’s strong, the cold air is contained in the Arctic. When it weakens or collapses, lobes or chunks of it break off and places like the U.S. experience cold air outbreaks.
The simplest, most helpful graphic of what the polar vortex is and is not was developed by the National Weather Service office in New York last winter, and is shown below:
(National Weather Service)
Here’s a great analogy (which NOAA’s Michelle L’Heureux used in an interview with the New York Times) to better understand the polar vortex: Think of a chain link fence, with weaknesses, circling the north pole. Within that fence, there are dogs constantly trying to break out. When a dog or two sneak through the fence, that’s similar to your typical cold air outbreak. But when the fence entirely collapses and you have a huge pack of dogs bursting through, that’s analogous to our really big, historic cold air outbreak, like we experienced last January.
Capital Weather Gang’s Rick Grow, in a blog post last year, discussed other great examples of the polar vortex collapsing from the 1980s to present. These less common events are distinct from regular cases in which a little lobe or filament of the vortex cycles south – like this week, and even this past summer. In this week’s case, the huge bulge in the jet stream in northwest North America being pumped up by the massive North Pacific storm is a better explanation for the cold in the East than the polar vortex.
Poor Alaskan/Western Canadian ridge gets no love, bigger cause for cold air than the #Polarvortex. pic.twitter.com/JL4ZfJdk50
— Brad Panovich (@wxbrad) November 10, 2014
Some meteorologists are becoming cranky when the polar vortex is blamed for the run-of-the-mill cold snap. I can understand that as it’s sensationalizing a common weather event. Washington, D.C. meteorologist Howard Bernstein of TV affiliate WUSA offered a spirited rant against polar vortex hype:
Bernstein’s point and the point a lot of other meteorologists are making is that the vortex’s involvement with our weather is usually nothing sinister and the term is being overused.
“If we called every push of cold air the polar vortex it would lose its meaning and not be accurate,” wrote meteorologist Ginger Zee of ABC’s Good Morning America.
I tend to agree that we need to be careful about labeling every cold air outbreak a “polar vortex” event. While it’s fine to discuss the role of vortex in a deep explainer about a given cold weather outbreak, media organizations should refrain from using the term in headlines except for the rare event in which the vortex is breaking down in unusual fashion.
Given the weather pattern shaping up this winter, a legitimate polar vortex collapse and intrusion towards the U.S. could well happen (maybe even next week?). So if you’re sick of hearing about the vortex, you better hide under a rock somewhere.
