GFS & GEFS: 10 hPa 60°N [U]

Climatological values use the full ERA-Interim record (1979-2019). Members exceeding 41.2 m/s are classified as having a “strong vortex event” following Tripathi et al. 2015, whilst those with winds below 0 m/s indicate either a major sudden stratospheric warming (SSW) or the final stratospheric warming (FSW). GEFS members with a strong vortex are only shown in blue if there are no members with easterlies, to avoid any potential overlap.

GEFS & GFS ensemble