Polar vortex winds at 60°N drop from 22.13 to 5.44 m/s in eight days in rare November disruption; major SSW remains forecast
A rare November disruption of the Northern Hemisphere stratospheric polar vortex is underway, with the daily-mean wind at 60°N and 10 hPa weakening from 22.13 m/s (49.5 mph) on October 25 to 5.44 m/s (12.2 mph) on November 2. Forecast guidance continues to indicate a possible brief reversal during the second week of November, which would meet the defining wind-reversal threshold used to identify a major sudden stratospheric warming, while any surface-weather response remains uncertain.

