The December PNA index was the most negative on record (1950-present), reflecting the amplified N Pacific/N America pattern. Past years with a large PNA index drop from Oct-Dec (mostly earlier decades) often saw high pressure over N Europe in Feb-Apr, cold in E Europe, low wind W pic.twitter.com/bXX3XTDwA9

— World Climate Service (@WorldClimateSvc) January 7, 2022