Rare November Polar Vortex Disruption Could Set Up a Colder, Snowier December

A rapid warming high above the North Pole is unfolding in the stratosphere and could disrupt the polar vortex within the next 10 days. Although this warming occurs far above the weather we feel at the surface, it can alter large-scale circulation patterns and raise the odds of a colder, snowier December across parts of the Northern Hemisphere.

What is happening

The stratospheric polar vortex is a ring of strong winds that normally confines frigid Arctic air over the pole. Scientists are observing a sudden stratospheric warming (SSW) — a rapid and pronounced rise in temperatures in the upper atmosphere — that is weakening those winds and may even reverse them. Amy H. Butler, a meteorologist at the National Oceanic and Atmospheric Administration, has noted the winds are weakening as this warming proceeds.

Why this matters

When the polar vortex weakens, the pool of Arctic air it contains can spill southward, allowing much colder conditions to reach mid-latitude regions in North America, Europe and Asia. Meteorologist Andrea Lopez Lang of the University of Wisconsin–Madison explains that once the vortex is disrupted it can take a month or more to recover, meaning surface impacts — such as colder temperatures and increased snowfall — can persist for weeks.

Timing and uncertainty

One notable aspect of this event is its timing. Judah Cohen, a research scientist at MIT, has pointed out that SSWs of this magnitude are rarely observed so early in November. Scientists caution that a major winter outbreak is not guaranteed: forecasting the timing, strength and geographic distribution of any resulting cold air is inherently uncertain and evolves as the stratospheric disturbance interacts with lower-atmosphere circulation.

Typical patterns and regional impacts

Historically, similar polar vortex disruptions have been associated with a ridge of warmer high pressure over Alaska and a downstream trough in the jet stream across central and eastern North America. That configuration can lead to colder and snowier conditions across the Central states and parts of the Eastern U.S. at times. However, the precise location and intensity of any cold outbreaks depend on how the disturbance propagates downward and across the hemisphere.

Observing challenges and the role of satellites

Monitoring the stratosphere depends heavily on satellite observations. Lopez Lang warns that some measurement streams are degrading as satellites age, and that program and budget decisions can affect the availability of current and future data. Reduced observational capacity would make it harder to detect, monitor and predict sudden stratospheric warming events and their downstream effects.

Bottom line: The stratosphere is warming rapidly and a rare November disruption to the polar vortex appears possible. That raises the chance of colder, snowier conditions for parts of North America, Europe and Asia over the coming month, but exact outcomes remain uncertain. Improved satellite monitoring and continued model guidance will be key to refining forecasts.

Scientists continue to track developments closely. Accurate monitoring and timely forecasts can help governments, utilities and communities prepare for potential cold outbreaks and winter storms.