I second BD, I was out Sunday and found 47-49 in mid-lake area between Cages Bend and Bluegrass. I bet it bumps into the 50's between yesterday and today given the sunshine.
It will probably be a couple degrees warmer back in the creeks. The main channel is still hauling pretty hard and it's probably going to warm up slow due to the large volume of cold water coming in from the Caney and Cordell Hull upstream.