Is it possible to have a lake turnover this early in the season?

I was on Oak Creek this past weekend and the fishing was awful. 2 fish in 3 days. We fished pretty hard too. The whole time we found bubbles coming up all over the lake. Water clarity was fine. I couldn't tell for sure because I don't fish in the late summer or fall all that often. I have seen a lake turnover once and I remember it being awful fishing as well.

Our 3rd day on the lake, Sunday, it was slick calm and while running around the lake there were bubbles coming up everywhere. I went and graphed some offshore spots and I never found a thermocline. I am convinced we experienced some kind of turnover but I just didn't think it would be possible this early and with only a small "cool" front as the catalyst.

Oak Creek has its days. Fished a tournament there last month, 30 people and I took 3rd with 3 fish for just shy of 10#. Only 1 person had a limit. Been there other times where 5 for 15 wasnt in the top 10.

Full moon weekend in early August means the fish are feeding at night. Same conditions at Ray Roberts both Saturday and Sunday and like you said we saw tons of bubbles coming up everywhere which is just a common thing, it's just that when it's calm you can see them. Lake turnover isn't going to happen till November on most Texas lakes.

It can happen.

A turnover is extremely unlikely. It takes a lot of cooling or a huge inflow of water/mixing to break thermal stratification in a lake.

There very well could have been an algae bloom crash. Those are natural and do sporadically happen during the late summer. The water will appear much clearer after a crash and the fishing usually suffers for a week or two. During a bloom crash dissolved oxygen levels can decline quite a bit, fish don't eat much when they're struggling to breathe. The bubbles could be from gasses produced by the decomposing algae at the bottom.

Not saying that's what happened, but it does line up. If that's what happened, a new bloom will establish in a couple weeks and things should go back to normal.

I have seen bubbles before. Just not the level of this magnitude. Why do you think the thermocline didn't show up on my graph then? I have fished it quite a bit this summer and every time I have seen the thermocline show up in around 17-20ft of water.

I’m out of town but wasn’t it “cold” and windy yesterday?

That can disturb the strata.

I'm sure you are not seeing a turnover.

You can double check my with your graph. Get in deep water and turn the sensitivity up.
You should find a point from 20 to 60 feet depending on water clarity where there is a distinct line on your graph. There will be fish above it but few under it.

It takes water temps in the mid 70's before you can start looking for a turnover.
Rain usually does not affect lake temps enough to force a turnover until the lake is close to that point or there is a lot of rain.

I did. I am well aware of how to find the thermocline on the graph. It has always been there every time I have fished it this summer. It was not existent when I scanned around this past Sunday. I couldn't believe it either.

That's odd. I'd be interested to see what a temperature probe would read at depth. Not being smart ---, just stating; there have been published studies that measured summer stratification in Florida lakes being almost unaffected by strong hurricanes. It takes a lot of energy to mix stratified water. Might drop a note to the tpwd district biologist to see if they've been on the lake recently.