PORTLAND PRESS HERALD • November 24, 2025
December could bring extra cold weather to Maine thanks to sudden stratospheric warming above the North Pole that could disturb the polar vortex. When the polar vortex is displaced or elongated, it can cause very cold air to spill southward into the United States. Long-range forecasts for this winter predict below-average temperatures across much of the northern parts of the country. Sudden warming in the stratosphere, the second layer in Earth’s atmosphere, is uncommon in November — it happened once in the 1950s — and its occurrence this week could become the earliest instance on record.