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): -9.6 m/s Weakest zonal wind at 10 hPa 60N in ERA interim record for todays date is: -5.8 m/s 2013

— PV-Forecast (@PvForecast) January 7, 2019