Overview
- Forecast systems show a 20–25°C stratospheric temperature spike over the Arctic with polar-vortex winds collapsing toward zero and in some runs briefly reversing.
- NOAA’s Climate Prediction Center cites La Niña, the Madden–Julian Oscillation and a possible November SSW as drivers of a significant pattern change late this month into early December.
- In North America, forecasters flag a turn to colder conditions after Thanksgiving from the Northern Rockies through the Midwest and New England, with Chicago and Boston areas likely to feel the early-December chill while California leans milder and quieter under a western ridge.
- In Europe and Canada, the Met Office says an SSW is looking likely with roughly 70% of past events bringing UK cold 10–14 days later, and Canadian outlets warn Ontario to prepare for below-seasonal temperatures and more frequent snow.
- Scientists underscore the rarity of a strong November event and warn that aging satellite assets and model spread limit confidence in the precise timing and geography of any downstream cold and snow.