Why are models suddenly blocking up the higher latitudes in the 11-15d, creating #wxporn 500mb geopotential height anomaly maps? The downward propagation of the -NAM anoms in association to the recent Sudden Stratospheric Warming finally penetrate the troposphere and kaboom. pic.twitter.com/4HXJA7wABC

— Mike Ventrice (@MJVentrice) January 15, 2019