In short, the Quasi Biennial Oscillation is an oscillation of east-west winds in the tropical stratosphere. During a negative phase (easterly) phase the brewer dobson circulation is sped up and allows for more frequent warming events in the stratosphere. The positive (westerly) phase slows down this circulation:
Where are we now...
We are in month 15 of the easterly phases! This means we are due for a reversal and a continuation of a decline as we head into N-D-J-F-M. As values continue to rise towards winter it will actually favor high latitude blocking, so long the values do not go to far into positive territory. Lets look at some similar winter:
Fairly good match up, but the major difference is the easterly phase lasted only 12 months and was weaker to start in October. Moderate to strong La Nina! Probably why we don't see this correlate well with high latitude blocking!
Easterly phase lasted 14 months and peaked same time as the 1998-98 analog and our current QBO. ENSO neutral just shy of el nino...similar!
19 month eastelry phase! Best analog yet and it also peaks in August like the rest. Weak to moderate La Nina.
17 month easterly phase, but peaks in June instead of August. Threw this analog in there to show the switch for winter. Weak El Nino.
Put this analog in there to show a rising qbo that stays negative. This is possible but notice that this easterly phase lasted 12 months. ENSO neutral but just shy of el nino status!
15 month easterly phase that rises into positive territory. ENSO neutral closer to La Nina.
The negative numbers and blue shading show high latitude blocking winters. Obviously the more negative the better the blocking (2009-2010). The only analog from above that is unfavorable for blocking is 98-99, which we can dismiss since it was a moderate to strong La Nina. Strong ENSO conditions wipe out the impact of the QBO
The two best analogs are 79-80 and 2003-04 because of the enso conditions, both show weaker values but still show high latitude blocking showing up. If we shift to a weak el nino (still possible) these numbers go down favoring more blocking.
The chances for a negative NAO to be around for most of the winter is looking better!
This could be a precursor to a significant east asian mountain torque event that could help out with rising stratospheric temperatures headed towards the poles in December. I would not be surprised to see December ending up warm as we still need some changes, despite a brief winter preview late in this month! But don't worry the pattern supports a return to winter at some point in December into winter! Below is the two best analogs I mentioned above showing a December that is on the warmer side with winter coming in strong behind it: