#MJO is expected to strengthen through Phases 5 & 6 next few weeks (into January), which coincides with #SSW. A strong Phase 5 & 6 are a precursor to a -NAO response (Cassou) increasing the incidence of northern blocking in NH https://t.co/m8KhyQzOsv pic.twitter.com/ywv1wP5FL7

— Dean Hall (@deanhall30) December 28, 2018