The GEFS took a while to get there — perhaps not completely surprising given their strong vortex bias at extended lead times — but are now finally on board with a sudden stratospheric warning (SSW) in early January, with numerous members showing a split vortex at 10 hPa: https://t.co/vhJAf1PXze pic.twitter.com/1ce5IhKCku

— Tomer Burg (@burgwx) December 24, 2023