Two weeks ago, subseasonal models were clamoring for a blocked high-latitude pattern in January (-AO phase), but since then the trend has been all the other way. Increasing signs of a vertically coherent strong polar vortex, with 10mb westerlies perhaps nearing record strength. pic.twitter.com/yYCWd3d6Va

— World Climate Service (@WorldClimateSvc) December 31, 2021