Taking the current model output and combining it with the general signal from CFS lately, the suggestion is that the PV will be under attack during the next 40-60 days, becoming increasingly unstable until an eventual disintigration sometime late in December or early in January.
The pace at which this unfolds has been increased by a large amount over the past fortnight, coinciding with the trend in GFS and ECM away from a strong PV dominating proceedings.
It seems that something, somewhere, has developed in favour of a blocked polar pattern developing by January. It might be the wave-breaking into the lower stratosphere, but I've not been following that closely enough to be sure (work demands...).
Originally Posted by: Stormchaser