![temperature maps for 2024 and El Ninos with SSWs](/sites/default/files/2024-05/Polar-Vortex-map-pair2-20240501.png)
If it weren’t for global warming, how much would this winter temperature pattern look like a typical El Niño winter when the stratospheric polar vortex winds do break down? (left) De-trended January-March temperature anomalies during 2024 (same as the left figure above) and (right) the average temperature anomalies during January-March El Niño winters (1958-2024) when at least one major sudden stratospheric warmings occurred. Anomalies correspond to departures from the 1958-2024 average temperatures. The two figures share many features over North America, Europe, and Asia, suggesting the modulation of El Niño’s influence on winter temperatures by the stratospheric polar vortex. Note that the amplitude of the 2024 temperature pattern is much larger because it’s a single year rather than the El Niño temperature pattern which is averaged over numerous years. NOAA Climate.gov image, adapted from original by Amy Butler.