Signs of Early Weakening in the Arctic Polar Vortex Raise Alarms for a Severe Northern Hemisphere Winter The polar vortex, a persistent upper-level wind circulation in the stratosphere over the Arctic, is exhibiting early indicators of weakening as of November 2025, according to analyses from the NOAA Climate Prediction Center and associated atmospheric monitoring efforts. This vortex typically forms a robust barrier of westerly winds encircling the North Pole at altitudes between 10 and 30 mile