The 8-15 day 500mb hemispheric forecast on all of the "big 3" ensemble suites (GEFS, EPS, & GEPS) is exactly the kind of pattern that's capable of greatly disrupting the stratospheric polar vortex later in December.

👀 pic.twitter.com/9Ft6cEIYpK

— Eric Webb (@webberweather) November 30, 2023