When the first snowflakes fall this November, they might not be a gentle preview—they could be the opening act of one of the most disruptive winters in decades. A rare and early Sudden Stratospheric Warming (SSW) event, forecast to strike around Thanksgiving week 2025, is poised to tear apart the Polar Vortex, sending frigid Arctic air plunging across the United States, Canada, and Europe. This isn’t just another cold snap. It’s a meteorological earthquake in the upper atmosphere, one that hasn’t occurred this early in over 70 years—and it’s coming at the same time as a lingering La Niña and a negative Quasi-Biennial Oscillation (QBO). The result? A winter that could feel like it’s stuck in the 1970s.
Why This Winter Is Different
Most winters are shaped by surface-level conditions: ocean temperatures, snow cover, jet stream quirks. But this one? It’s being dictated from 30 kilometers up. At the 10mb level—the stratosphere, where jet planes never fly—a massive high-pressure dome is forming, compressing the Polar Vortex like a fist squeezing a balloon. According to severe-weather.eu, this could trigger a full wind reversal: from westerly (the normal direction) to easterly. That’s the technical definition of a major SSW. And it’s happening in late November, when such events are almost unheard of.Here’s the twist: even if the wind doesn’t fully reverse, the disruption alone is enough. The Polar Vortex doesn’t need to collapse to send cold air south—it just needs to wobble. And models show it’s going to wobble hard.
The Perfect Storm of Atmospheric Forces
This isn’t one factor. It’s a cocktail.- La Niña: The National Weather Service gives a 61% chance La Niña will persist into early 2026, cooling Pacific waters and shifting storm tracks. Historically, early La Niña winters were colder—but recent decades have softened that trend due to warming. This one? It might break the pattern.
- QBO in easterly phase: The Quasi-Biennial Oscillation flips every 28 months on average. Right now, it’s in its easterly (negative) phase, which, as Arcfield Weather notes, nearly doubles the odds of a disrupted vortex. Combine that with La Niña? That’s a 90% chance of a cold winter in the eastern United States and northern Europe.
- NAO in negative territory: The North Atlantic Oscillation has plunged into negative, meaning high pressure over Greenland and low pressure over the Atlantic. That’s a blocking pattern—a traffic jam in the jet stream that traps cold air over the Midwest and Northeast.
Together, these forces don’t just make winter colder—they make it stuck. Snowstorms won’t be fleeting. They’ll linger. And repeat.
What to Expect, When, and Where
Thanksgiving week 2025 is the tipping point. delainelebas.com and climate.ncsu.edu both warn that the upper-level winds will weaken dramatically during that week, opening the door for a polar air surge. By mid-December, the Polar Vortex could be visibly distorted on satellite imagery, with a cold tongue stretching from the Canadian Arctic down through the Great Lakes and into the Ohio Valley.
January through March? That’s when the real trouble could start. Powderchasers forecasts a 1-to-3-week window of high-latitude blocking—essentially, a frozen pause in the weather system. During that time, the Northeast and Midwest could see multiple snow events, each heavier than the last. The West Coast might dodge the worst cold, but the marine heatwave in the Northeast Pacific could mean wetter storms—and higher freezing levels, turning snow to rain at lower elevations.
Europe won’t be spared. The British Isles, Scandinavia, and northern France are all in the crosshairs. The same jet stream collapse that dumps snow on Buffalo could dump 2 feet on London.
Historical Context: This Isn’t Normal
The National Weather Service notes that while La Niña winters used to mean snowier, colder conditions across the U.S., the last decade has seen a warming trend soften those impacts. The 10 most recent La Niña winters were milder than the 10 before them—by nearly 2°F on average. That’s the fingerprint of climate change.
But here’s the paradox: climate change isn’t making winters disappear. It’s making them more extreme. Warmer oceans fuel more moisture. A weaker, wobbly Polar Vortex lets cold air escape. The result? Snowier winters in some places, even as global temperatures rise. It’s counterintuitive—but it’s physics.
What’s Next? The Watch Begins
The next two weeks are critical. If the stratospheric high-pressure system holds and the wind reversal occurs, this forecast will solidify into a historic winter warning. Meteorologists are already comparing this setup to 2013–2014, when the eastern United States endured the "Snowmageddon" winter, and 2020–2021, when the Texas freeze crippled the power grid.
Residents in the Midwest and Northeast should start preparing now: check heating systems, stock emergency supplies, and keep snow shovels handy. Utility companies are already bracing for higher demand. And for the first time in years, ski resorts might actually get the snow they’ve been praying for.
Why This Matters Beyond the Cold
It’s not just about snow days and frozen pipes. A prolonged cold snap means higher energy bills, strained transportation networks, and increased health risks for the elderly and unhoused. Crop storage in the Great Plains could be threatened if freezing temperatures hit early. And if this pattern holds into March, it could delay planting seasons—potentially affecting food prices later this year.
What’s happening isn’t just weather. It’s a stress test of how our infrastructure, emergency systems, and even our sense of seasonal normalcy are holding up in a changing climate. This winter might be a preview of what’s to come: more volatility, more extremes, and more surprises from the upper atmosphere.
Frequently Asked Questions
How does a Sudden Stratospheric Warming cause cold weather at the surface?
A SSW disrupts the high-altitude Polar Vortex, weakening the jet stream that normally keeps Arctic air locked north. When it weakens, the jet stream dips south in a "wave," allowing cold air to spill into the U.S., Canada, and Europe. This isn’t a direct transfer—it’s a domino effect from 30km up to the ground.
Is this winter going to be colder than 2022–2023?
Yes, likely. The 2022–2023 winter was unusually mild across much of North America due to a strong, stable Polar Vortex. This year’s forecast combines multiple factors—La Niña, negative QBO, and early SSW—that historically lead to colder-than-average conditions, especially in the eastern two-thirds of the U.S.
Will the West Coast get snow too?
The West Coast may see wetter storms due to a marine heatwave boosting moisture, but the cold air won’t penetrate as deeply. Higher freezing levels could mean rain at lower elevations, though the Sierra Nevada and Rockies could still get significant snow, especially if the jet stream dips far enough west.
Why is this SSW happening so early?
There are fewer than five recorded SSW events this early in the past 70 years. The current stratospheric high-pressure anomaly is unusually strong and forms earlier than typical due to a combination of tropical convection patterns and polar ozone dynamics—both influenced by long-term climate shifts.
Could this lead to a "polar vortex" event like in 2019?
Possibly. The 2019 event was one of the most extreme in recent memory, with temperatures below -40°F in the Midwest. If the vortex splits rather than just weakens, we could see a similar—but not identical—scenario, especially if blocking patterns persist into January.
What role does climate change play in all this?
Climate change doesn’t eliminate cold winters—it makes them more erratic. Warmer Arctic regions reduce the temperature gradient that stabilizes the Polar Vortex, making disruptions more likely. Meanwhile, warmer oceans add moisture, leading to heavier snowfalls when cold air does arrive. So yes: global warming may be fueling this extreme winter.
