Overview
- Models project an unusually early sudden stratospheric warming in late November, with temperatures aloft surging roughly 40–50°C and stratospheric winds slowing enough to disrupt the polar vortex.
- Long‑range guidance favors below‑average temperatures across parts of about 35 states into December, with higher odds for colder conditions across the northern U.S. and the Great Lakes.
- Potential local effects around the Great Lakes include increased chances for lake‑effect snow, travel slowdowns, and windy storms, though exact totals and locations remain uncertain.
- Such events typically take weeks to influence surface weather, so the earliest widespread effects are most likely in early to mid‑December rather than immediately after Thanksgiving.
- November SSWs are rare in records since the 1950s, and scientists caution that not every event produces strong surface cold, western U.S. outcomes are less clear, and there is no consensus on any climate‑change link to their frequency.