Will A "Sudden Stratospheric Warming" Postpone Spring?

Just one forecast for temperature anomalies in the 
lower stratosphere toward the end of this week. All that
orange represents something called a Sudden 
Stratospheric Warming. This can disrupt the polar vortex,
which in turn can cause cold, stormy weather in
the mid-latitudes in March. 

As I keep harping on, it's been a warm winter. Really warm.

Since the winter of 2022-23 is turning out to be a dud for cold and snow lovers, a lot of people are probably saying, "Let's get on with spring already, then."

Not so fast.

Because Ma Nature seems intent on punishing us awful humans, she's launching something called a "sudden stratospheric warming."

It could mean that winter finally hits - in March. 

As the Washington Post reports: 

"Several miles above the North Pole, an atmospheric chain reaction may soon initiate that sets off important changes to the weather pattern across the Northern Hemisphere in the coming weeks. 

In places where cold and snow have mostly remained absent, the sequence could trigger a wintry revenge. However, it's still unclear how significant or long-lasting any changes may be and exactly where and when they would occur."

The not all that well understood phenomenon starts with the stratosphere over the northern reaches of the Earth suddenly and abruptly warms up, by as many as 60 degrees.

When this happens, it usually disrupts the polar vortex, that whirl of cold that's usually somewhere up in the Arctic.

The polar vortex has been mostly "well behaved" this winter, sitting high up in the Arctic. That has for the most part prevented very cold air from plunging into places like the United States and Europe.  Which explains the warm winter both areas have had. 

The polar vortex did get disrupted for other reasons recently, making it plunge down toward New England and give us that brief bitter blast of Arctic air on February 3 and 4. But, the vortex quickly got its act back, together, and settled itself far to the north again. That's why it has once again warmed up.

A sudden stratospheric warming is more likely to disrupt the polar vortex. That means weather mischief somewhere in the mid-latitudes. Think the United States, southern Canada, Europe, China, Japan, places like that. 

Even if we do see that sudden stratospheric warming, or SSW, we don't know if it will have a big effect or whether it will be a nothing burger. If it does have a large impact, we don't know where that might be as of yet. Could be the western U.S., or could be the East, who knows? Or it could focus on Europe.

Whatever happens, generally speaking, the effects of a SSW last four to six weeks. 

The most recent example of a big headache created by a SSW, we only need to harken back to late February and March 2018. 

In late February, 2018 the so-called "Beast From The East" slammed Great Britain. Frigid winds from Siberia flowed westward to the UK, causing some of the most intense cold and blizzards in recent memory.

More locally here in Vermont, we had a remarkably warm February, 2018 which culminated in temperatures as high as 70 degrees in Montpelier, which is their all time hottest temperature for February. Burlington reached 69, which would have been the hottest February reading ever if not for a 72 degree temperature spike the previous February.

Then came March, 2018, once that year's SSW took full effect. In mid-March, up to 30 inches of snow fell in Vermont. Along the New England coast, four snowy nor'easters battered the region during the month. 

It really took until late April, 2018 for temperatures to consistently return to normal or above.

Of course, 2018 was almost a worst case scenario. Chances are it won't be that bad. Or if it is, it won't last as long, Or it won't affect us here in Vermont all that much. You never know. 

The last SSW to occur was in January, 2021. That helped lead to a record breaking cold wave in the Plains and Southeast in February, 2021. It focused on Texas, causing deadly blackouts amid the cold, killing dozens of people. 

That 2021 event was a yawner here in Vermont. We just kind of had average weather in February and and March that year. 

A SSW more often affects the weather in northwestern Europe than it does the United States, but the U.S. sees the effects often enough. I'm betting on at least some cold weather in March here in Vermont. That means more frequent below normal temperatures than we saw in January and February.

If the SSW actually happens, it will probably begin this week if it hasn't already started.  It takes a week or two after the stratospheric warming to have much effect on where people live.,

That would take us into early March. 

It's a little too soon for long range forecasts to accurate predict what the weather will be like in early March.  But some of the preliminary long range computer projections seem to indicate a switch to colder, stormier weather in the eastern U.S., including New England, possibly arriving in the last few days of February and continuing at least into the opening days of March.

That's not set in stone, but the chances are there. 

Besides, we're overdue for a colder than average month in Vermont. February will be warmer than normal, meaning the last time we had a chillier than average month in Burlington was September. Even that was a fraction of a degree cooler than normal. And it was the "new normal" which is skewed toward warmer averages than decades ago.

And remember this non-scientific adage that has always worked for me: No good weather in Vermont goes unpunished. If you got a break in the weather in one month, you'll pay dearly the next.