Before I tripped to the lake, I watched a video of such a cooler full. They weren't fishing the warmer water however. They were fishing the cooler water in timber nearer the inlet. But this was in the September -October time frame. They however were not challenged with BG interference. All the caught were TP (on earthworms). The fishing was good in that video with one fish after another ... so they had dialed in on a situation where the TP were concentrated but the BG were not. I think they were were suspended in timber IIRC.
I think there are cases where anglers find them concentrated in warmer water but one must keep in mind that the water Temps are changing rapidly during this time period. One has to locate where they are concentrated. There are limits to how close one can approach the plant.. so you have find them at preferred Temps before they enter the forbidden space.
