polar-vortex_winds_graph.png

In early December 2023, NOAA's Global Ensemble Forecasting System (GEFS for short) began hinting that the winds of the Northern Hemisphere polar vortex might be about weaken. The spread of the individual forecasts is still pretty wide (thin pinkish-purple lines), but the average (heavier, bright purple line) predicts that winds will be weaker than average (royal blue line) in December. Climatology of highest and lowest daily values is from Climate Forecast System Reanalysis. NOAA Climate.gov graph, adapted from original by Laura Ciasto.