Here’s a very much non-exhaustive list of websites I use to keep an eye on what’s happening (or has happened) in the stratosphere.
Tomer Burg’s stratosphere plots
NASA Ozonewatch (MERRA-2, GEOS data)
CPC Stratosphere-Troposphere Monitoring
JMA Climate System Monitoring: Stratospheric Circulation
Judah Cohen’s Arctic Oscillation and Polar Vortex Analysis and Forecasts
CPC Stratosphere Global Temperature Time Series
CPC Meteorological Conditions and Ozone in the Polar Stratosphere
CPC Stratospheric Intrusion Monitoring
Simon H. Lee 