Image caption
Observed (bold blue line) and forecasted (NOAA GEFSv12, pink lines) polar vortex wind speeds at 60°N compared to the 1991-2020 average (data from CFSR, thin blue line) and the natural range of variability (blue shading). Around March 9, 2025, the winds at this location reversed direction, indicating a major polar vortex disruption. In the second half of March, the winds made three failed attempts to resume their westerly direction. During the last attempt, the stratospheric winds reached minimum values of -28 meters per second, which are the most strongly “opposite” polar vortex wind speeds at 10-hPa recorded for this time of year since 1991. NOAA Climate.gov image, adapted from original by Laura Ciasto.