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| Something called a Sudden Stratospheric Warming could easily flip us in Vermont to a much colder, snowier pattern toward the end of the month. |
The event is something called a "Sudden Stratospheric Warming," which sounds ominous enough for people to ask what fresh hell is this going to be.
Before you panic, Sudden Stratospheric Warming," or what we'll all SSW for short, isn't another sign of the apocalypse. Though it does have the potential for making it kind of unpleasant to be outdoors for awhile.
CBS meteorologist Jeff Berardelli has a great, detailed explainer on this, but I'll also give it to you in a nutshell.
What the SSW involved was the temperature in the stratosphere, about 50,000 to 100,000 feet overhead suddenly jumped by 100 degrees, which of course is a LOT.
Major SSW's like this one is, happen on average perhaps six times per decade. So it's relatively rare, but nothing we haven't easily dealt with before.
This sudden warming screws up the Polar Vortex, which is another thing you've probably heard hyped quite a bit in recent years.
To review, the Polar Vortex isn't some new hazard that cropped up in recent years. It's always been there, especially during the winter, and it's completely normal.
The Polar Vortex is just a huge spinning mass of frigid air near the Arctic. This vortex can move around quite a bit, and pieces of it can break off. If the Polar Vortex gets relatively close to us, or a piece breaks off near us, it gets bitterly cold in these parts. Just one of those Arctic outbreaks we Vermonters should be used to by now.
When a SSW happens, it can rip the Polar Vortex apart, splitting it into two, three or even four pieces. Those Polar Vortex pieces then head south toward the mid-latitudes, causing frigid, stormy weather in places where lot of people live, like Europe, Asia, southern Canada and the United States.
This turn to cold and stormy weather is already taking place in parts of Europe and Asia.
It's only a matter of time before the SSW and the messed up Polar Vortex pieces will end our mild, quiet weather around here.
Just how that will play out is the question.
It can easily get colder around here than it's been, and it certainly can't get much quieter in terms of storms.
As things develop, it seems like it will temporarily turn even milder here next week as the jet stream buckles and allows frigid air to flood first into the northern Rockies and upper Plains states next week.
Eventually, later this month, the cold air probably comes our way. The new pattern caused in large part by the SSW also seems favorable for East Coast snowstorms, but again, the devil is in the details. There are no guarantees of how much snow we might get later this month.
We also don't know where the core of the cold air might set up. It could set up well to our west, so we'd stay relatively close to average for winter. Or, the cold waves we'd get would be sort of brief and not anything to write home to ma about. We'll just have to wait and see.
There's also no guarantee as to how long the effects of the SSW will last. They rough weather often continues for four to eight weeks, but it won't be constant cold and snow. It would just be chilly and snowy most of the time, with a few warmer breaks thrown in.
As Berardelli writes, it's possible climate change might be making these SSW's more likely.
One theory being explored is that a lack of Arctic sea ice might play a role in triggering SSWs. Sea ice up there has been low for years now, as the Arctic has warmed faster than the rest of the planet due to climate change.
The lack of ice allows more warmth and moisture to enter the atmosphere as it takes longer for ice to re-form in the autumn. This, in turn, seems to cause some changes in the wintertime jet stream over northern Asia.
We saw record high pressure over Mongolia earlier this winter and record low pressure in the northeast Pacific. All these things that I've just described can lead to a SWW or are symptoms of it. Berardelli gets into much more detail on this, and it's worth the read.
There is still some conflicting evidence, but indications are that the SSWs are getting more frequent with the diminishing ice up in the Arctic.
That screws up life for us. While the climate and winters around here are generally getting warmer (this winter so far is Exhibit A), places like the Northeast and parts of Europe are apparently getting more prone to intense winter cold waves and epic snowstorms that interrupt this generally warming scenario.
As noted, we don't know exactly how the weather will play out here in late January and February due to this SSW, but it sure looks like our mild winter is going to get less so.
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