A key factor influencing month-to-month PDO (Pacific Decadal Oscillation) is ENSO (with some lag), another one is general circulation over the N. Pacific. I would argue that the latter, with a persistent strong N. Pacific jet, has had a greater impact lately: pic.twitter.com/sKyLMYiKDs

— Il neige (@jacquesmainguy) October 10, 2021