Overview
- New NWS Climate Prediction Center outlooks raise the odds of below-average temperatures in the Northern Plains, Upper Midwest, Great Lakes and parts of the Northeast in the 8–14 day period.
- NOAA’s Amy Butler says some models place the sudden stratospheric warming as already under way and others near November 28, with forecasts putting it on the threshold of a major event.
- Butler cautions that the near-term chill in some guidance likely stems from a developing Alaskan ridge, with any stratospheric influence more likely to emerge over the next several weeks.
- Early-season SSWs are uncommon, and Boston Globe reporting notes this could be the earliest unstable polar vortex since the 1960s, with New England likely on the fringe of the deeper cold.
- Scientists stress that SSWs shift probabilities rather than guarantee outcomes, as about two-thirds of major events affect surface weather and other drivers such as La Niña and the MJO also shape the pattern.