Unfortunately we have a strong +QBO coming. With La Nina, even weak, that's a really strong 10mb vortex, normally.
The last 2 times we have kind of cheated a little at the surface
even 3
I don't know that the season will be below average, 15 is the lowest I can think would happen. If we do 12,14, the Winter may be cooler in the Hemisphere. I guess we have signs of that with a trough holding in the east..