Nice intrusion of strat air happening- this is actually associated with the filaments peeling off polar vortex as it breaks down! (thanks to P. Newman for pointing this out). These events can have impacts on air quality. You want stratospheric #ozone to stay in stratosphere! pic.twitter.com/QWh5bt7aLb

— Dr. Amy H Butler (@DrAHButler) January 2, 2019