Ready for winter? Polar vortex spins up, spews forecast uncertainty

Ready for winter? Polar vortex spins up, spews forecast uncertainty A solid polar vortex and a powerful El Niño would be signals that a milder winter may be in store for numerous Americans.

Key points

• The infamous and often misunderstood polar vortex obtained off to a powerful start in 2026, but don't rush out to purchase a parka.
• It's already among the strongest on record and still strengthening, remarked Jon Gottschalck of NOAA's Climate Prediction Center.
• El Niño already is influencing weather and climate, especially in the tropics where there have been 18 named tropical cyclones in the eastern Pacific, remarked Gottschalck.
• Dinah Voyles Pulver and Doyle Rice are national correspondents for USA TODAY, focused on climate and weather.
• One of the biggest questions: Which Americans will experience a generally mild winter and who will suffer periods of intense cold?

For context, the polar vortex is returning, and it is stronger than normal over the Arctic.

Meanwhile, the infamous and often misunderstood polar vortex obtained off to a powerful start in 2026, but don't rush out to purchase a parka.

First of all, a solid polar vortex signals a milder winter (hence it being often misunderstood).

Secondly, the vortex has already evolved since its start in late summer.

And finally, forecasters aren't yet ready to matter a winter outlook, but they're closely watching for clues concerning what's in store for a season that will probable be shaped by a historic El Niño.

Notably, a powerful El Niño makes the mild winter scenario more probable for most Americans.

"We have a super El Niño this winter and that has blotted out the sun for the forecast community, " remarked Judah Cohen, a climatologist at the Massachusetts Institute of Technology.

For context, a solid polar vortex would additionally create mild weather more probable. When it's solid, the intense cold of the polar regions stays bottled up in the Arctic.

But if disrupted by chaotic climate forces, a disturbed polar vortex could still support send freezing air into the nation.

"If El Niño is a full-length movie, then the polar vortex might be a scene within the movie, and the characters are the day-to-day weather systems, " remarked Simon Lee, an atmospheric scientist at St. Andrews University in Scotland. Milder winter? Forecasters watch 2 key forces.

El Niño will loom sizeable in this year's winter weather outlook, stated a number of scientists contacted by USA TODAY.

It's already among the strongest on record and still strengthening, remarked Jon Gottschalck of NOAA's Climate Prediction Center. The temperature and precipitation outlooks for the winter are consistent with the impacts "often observed for strong eastern Pacific El Niño events."

MIT's Cohen remarked "every forecast I have seen, pretty much 100% follows the El Niño script with a nod to the warming trends we have observed over the observational record. If anyone else is considering anything else, I haven't seen it."

Meanwhile, the polar vortex obtained out of the gates "record strong" this year, Cohen stated.

As projected, as the amount of sunlight reaching the North Pole kicked off to decline, remarked Amy Butler, an atmospheric scientist at NOAA, the polar vortex formed around the end of August.

Nevertheless, the quick-to-change polar vortex has since morphed back to a bit weaker state, Cohen went on: "The polar vortex is no longer record strong and it is actually a bit weaker than normal as it is undergoing a polar vortex stretch."

He remarked the stretch will take place all this week before snapping back to a more normal configuration or state. "It looks like that over the next two weeks the PV will be near normal or slightly weaker than normal, " Cohen remarked.

If the vortex weakens during the heart of winter, it can allow bitterly cold air to slosh down into the central and eastern United States.

For context, the wintertime phenomenon is a key feature forecasters look at to understand how the weather can vary from week to week, Lee remarked. It's a bit different from something like El Niño. It tells us more regarding how the average weather will probable evolve for the winter as a whole.

It's too early in the season for the vortex to have had much impact, Lee remarked. "Forecasters will start looking toward the vortex from around November onwards." How El Niño and the polar vortex may interact.

One of the wild cards in the winter forecast is how El Niño will affect the polar vortex.

For context, the relationship between the vortex and the El Niño Southern Oscillation – the pattern that includes both El Niño, La Niña and a neutral phase – is not yet well understood and doesn't appear to be particularly solid, Cohen stated.

During the three previous strongest El Niños, there weren't polar vortex disruptions, Butler remarked. A solid El Niño this winter could raise questions concerning its influence on the stratosphere, where the polar vortex lives.

In practice, the scientists will be watching development of repeated high- and low-pressure systems, to see if solid low pressure systems amplify waves into the stratosphere that could disrupt the polar vortex. A disruption of the polar vortex is a weakening, stretching or displacement of the stratospheric circulation that can allow frigid Arctic air to spill southward and raise the risk of cold outbreaks and winter storms.

Since the typical El Niño brings warmer-than-normal conditions to much of North America, Lee stated it could support to weaken the polar vortex and raise the odds of colder conditions afterwards in the season.

Even if the relationship between the two atmospheric influencers starts one way, it can flip in early winter, compared to late winter, Butler remarked, from a stronger polar vortex in early winter to a weaker one afterwards.

When could we commence to see El Niño's influence in our winter weather?

Now forecasters will be watching for changes at higher latitudes. It typically commence in late autumn and peak in mid-winter, he stated.

El Niño episodes tend to lead to deeper than normal low-pressure systems in the North Pacific, driving a stronger jet stream that brings stormier and wetter conditions to the West Coast, remarked Lee.

If storms start lining up one after another to slam California afterwards this fall and especially into late December, then the impacts of El Niño would be on track, Cohen stated. If that doesn't happen, he remarked, "there could be some big surprises in store."

While we can obtain a sense even now of how El Niño may affect the polar vortex, we can't predict a polar vortex disruption earlier than 10-14 days ahead of time, unfortunately, according to Butler.

That window "limits our ability to incorporate stratospheric information into the winter outlook to some extent, because the timing of the colder weather risk is linked to when the polar vortex disruption actually occurs, " Butler remarked.

According to Cohen, "For me, October is a critical month but I don't want to get too far over my skiis and don't want to speculate too much." Is climate change a factor?

One thing to remember is that all the seasonal factors, such as El Niño and the polar vortex, are occurring against the backdrop of a world that's warming over decades due to human-caused climate change.

"It's important to recognize that climate change means cold episodes in winter are much warmer than they would otherwise have been, " remarked Lee. "Our rapidly warming climate also means that what may seem cold now would often have been relatively normal just a few decades ago."

Dinah Voyles Pulver and Doyle Rice are national correspondents for USA TODAY, focused on climate and weather. Reach them at [email protected] and [email protected]. SMS Facebook Twitter Email. Share your feedback to support improve our site! Share your feedback to support improve our site!

Taken together, the developments around ready for winter? Polar vortex spins up, spews forecast uncertainty point to a situation that is still moving, and the coming days should bring more clarity.