Mid-November has turned out more interesting than I was anticipating, but not in terms of the immediate weather, rather the bigger picture.
Long story short, I've been noticing some sacrificing of the potential depth and persistence of cold weather across the UK in the final third of November, in exchange for increased potential in Dec generally, via raised likelihood of blocking patterns that also have more potential to disrupt the polar vortex.
Notably, blocking highs across the Urals have begun to appear in some model projections for late Nov / early Dec. This has been majorly missed in the past fortnight, as it's a key instigator of stratospheric warming events.
During a La Nina December, an inherent tendency for high pressure to locate west of the UK means that only a weakened polar vortex is required to open the door for some notable -NAO episodes; we don't need a SSW to do the trick.
Uncertainty is still considerable, mind. Especially with the La Nina having changed shape a little in the past week, the largest cold anomalies now being focused in the eastern rather than central Pacific. This takes it away from the 'classic' La Nina configuration and reduces support for a -NAO in Dec while considerably increasing it in Jan-Feb.
That could prove a major wildcard for this winter, if the largest cold anomalies remain in the east Pacific. Also uncertain... the joys of long-range forecasting!