The Polar Vortex Just Broke a 68-Year Record—and We May Pay the Price at Thanksgiving

The Northeast got a preview of winter this week thanks to a record-early polar vortex disruption. This unprecedented meteorological event sent Arctic air into the U.S., dragging temperatures down enough for a nor’easter to drop the first significant snowfall of the season in some high-altitude areas. Now, meteorologists say a second wave of cold may be on the way. On November 11, the winds of the stratospheric polar vortex—a large current of low pressure and cold air that spins counterclockwise around the North Pole—reversed direction. Scientists call this phenomenon a “major sudden stratospheric warming” (SSW) event, and this one occurred about two and a half weeks earlier than any observed since modern record keeping began in 1958. The polar vortex keeps frigid air locked up in the Arctic, but an SSW can distort it and cause cold temperatures to spill southward into the mid-latitudes. That’s why it was markedly colder across much of the eastern U.S. this week. Forecast models suggest the eastern U.S. could see another dip in temperatures—and possibly more snow—around Thanksgiving weekend. “I think we’ll see a return to more wintry conditions, but it’s a bit TBD as to how severe,” Judah Cohen, a climatologist at the Massachusetts Institute of Technology and leading polar vortex expert, told Gizmodo. That will depend on how the polar vortex disruption unfolds over the next two weeks. At this time, Cohen said he does not expect the U.S. to see extreme cold but added that “some of the models have some really juicy ingredients for a blockbuster storm.” An unusual atmospheric setup Major SSW events typically occur between January and February. It’s not exactly clear why this one occurred so early, but some studies have linked El Niño to a weaker polar vortex and more frequent SSW events. By some metrics, the current El Niño is already the strongest on record, and it’s still intensifying. So, it’s certainly possible that it played a role in this early disruption. Andrea Lopez Lang, a meteorologist at the University of Wisconsin-Madison, told CNN that the unprecedented timing of this sudden stratospheric warming event makes forecasting its impacts difficult. “It’s happening so early in the season that basically our historic events don’t capture what’s actually happening,” she said. The fact that this event is unfolding against the backdrop of a super El Niño further complicates forecasting. “There is no observed November SSW event in a similar global setup,” meteorologist Andrej Flis wrote in a blog post for Severe Weather Europe. “For this reason, I searched thousands of simulated winters from global climate models to find such events and what happened in those cases to the weather below.” His analysis reinforces the idea that a significant portion of the United States—particularly the East—could see an intrusion of Arctic air and increased chances of snowfall over the next two weeks. But again, the exact location, timing, and severity of impacts remain to be seen. This early polar vortex disruption is expected to kick off a winter of anomalous weather driven by El Niño and climate change. As for the Thanksgiving forecast, “it is a fluid situation, and the models will struggle, so we wait and watch how this unfolds,” Cohen said.