The strat. vortex is currently weaker than all other years in the ERA interim record!!! The zonal mean zonal wind at 10 hPa 60N is today (GFS analysis): -8.3 m/s Weakest zonal wind at 10 hPa 60N in ERA interim record for todays date is: -6.9 m/s 1985

— PV-Forecast (@PvForecast) January 5, 2019