It will definetely have an impact on the fishing, from prior to the rains. Anyone who pre-fished can throw out anything from that.
It all depends on how the river is changing the temperature in the lake. Possibly fishing up river in the mud and current will be better, but you never know.
If not, I would just try throwing a spinnerbait at wood and hope to get lucky. At least when you are throwing a spinnerbait, it keeps you warmed up. Dragging a jig craw or a worm all day and not getting bit can be demoralizing.
With 180 boats out there though, somebody is going to bring some fish in.