Early polar vortex disruption forecast
The gist
Models show the polar vortex weakening and possibly splitting in early November, the earliest such disruption observed.
It usually happens in mid-winter, so what it means for winter cold is uncertain.
How it unfolded
- Oct 22, 2026Forecasts indicate an unusually early polar vortex disruption, with all major models agreeing the vortex will weaken toward early November below the historical low for this time of year.
- Oct 27, 2026Models signal a potentially significant early-November disruption, possibly the earliest major disruption or sudden stratospheric warming on record.
- Nov 3, 2026NOAA meteorologist Laura Ciasto observes the vortex "stretched out and splitting into two smaller vortex lobes"; NOAA acknowledges the potential for an unusually early warming event.
Key terms
- polar vortex
- A large region of cold, rotating air encircling Earth's polar regions, in the stratosphere and troposphere.
- stratosphere
- The second-lowest layer of Earth's atmosphere, above the troposphere and below the mesosphere, where temperature rises with altitude.
- sudden stratospheric warming
- A phenomenon where polar stratospheric temperatures rise sharply within a few days, often linked to polar vortex disruption.
Source: Wikipedia