A pattern change appears to be finally in the works as a stable...four wave flow regime with an anti-cyclone parked over the Pole sets up by D+10.
Initial state starts with the 'never-say die' blocking ridge over the Bering Sea and a deep trof in the Gulf of Alaska where SSTAs are below normal thanks to the PDO.
These two persistent teleconnection features have kept the PNA underwater for months...wasting the cold air potential of a negative AO and its sister index..the NAO.
All that is forecast to change in 10 days as the Bering Sea HIGH becomes pinched off and shoved to a position directly over the Pole...where its circulation is re-enforced by the flow around four trofs at lower latitudes.
This scenario was more-or-less forecast by PSD's GFS '8-14 day' ensembles earlier in the month altho the model had the change in place about ten days too soon.
Even the GFS shows large chunks of arctic air reaching the Gulf of Mexico and Miller 'A' storms moving along the east coast.
Images courtesy Plymouth State Wx