Polar Vortex 2024 2025. As you can see, a la niña phase has a higher chance of producing a polar vortex collapse event. The weakest polar vortex years (dark green dots) occur in easterly qbo winters.
For the gefsv12 forecast issued on 18 december 2024, the winds at 60 degrees north (the mean location of the polar vortex) are forecast to remain stronger than normal for at. During the peak of ozone depletion season from sept.