If the QBO keeps trending to neutral/negative, combined with near solar min, favorable tropospheric forcing mechanisms that act to weaken the PV, and potentially weak Nino forcing, we may end up with a -AO and by association a -NAO. No one knows exactly how the HL look will evolve. Its difficult to predict at long lead times. I can see a case for some relatively short lived blocking in the near term, a relaxation, then a more significant NA block developing later in winter. Hopefully the PNA/EPO/WPO will be generally favorable when the NA is less so.