How to tell if it will probably be a good strong year for fall blooms?
Perhaps by how tall and thick the goldenrod is prior to blooming? A couple years ago we had a great fall flow and prior to bloom, the goldenrod was taller (over 6') and more prevalent than I had remembered ever seeing it before.
In my area, you can't predict because so much depends on the rain we get [or not] during the fall. I get acres of blooms, but if it has been really dry, there's no nectar in those blooms.