West QBO has descended below 30 hPa but the lower stratosphere remains in an eQBO favoring tropical tropopause upwelling & upward propagation of Kelvin Waves to the westerly shear zone. Worth re-iterating that SSWEs occur most often during an eQBO >> wQBO transition. H/t @splillo pic.twitter.com/k9cfT811zb

— Eric Webb (@webberweather) November 5, 2018