Spotty storm chances Friday & Saturday ahead of widespread rain
We're almost there...the weekend is right around the corner. I've been enjoying these cooler temperatures, but we may see 90° by this weekend.

For today, however, we will enjoy a mostly dry day with temperatures in the mid 80s. I can't rule out a rogue shower, otherwise we will not see rain this afternoon or evening. Temps cool off tonight comfortably into the lower 70s and upper 60s.
Friday unfortunately holds higher rain chances, but the good news is those chances decrease by Friday night football kickoff. It wouldn't hurt to pack a rain poncho as you head out to the football field, but I think we stay mostly dry. For Friday afternoon, spotty storms may dump some brief but heavy rain. Friday is going to be your typical summer afternoon storm pattern.
Saturday holds an isolated storm chance in the afternoon hours as well as the overnight hours. However, I want to focus in on a pattern change coming to the Tennessee Valley beginning Sunday. I'm going to walk you through two model outputs, the GFS and ECMWF. This is model data, not exactly a forecast. I'll put my thoughts at the end.
The GFS model is drier than the ECMWF overall. It doesn't have widespread rain moving in until Sunday afternoon. It also shows a drier Monday morning and frankly not much rainfall Monday afternoon either. This model is hinting at Sunday being the wettest day of the two.
Now to the ECMWF. This model is quicker to bring in the heavy rain, and it shows heavier rainfall compared to the GFS model. The ECMWF continues the rain chances through the overnight, Monday morning and afternoon.
These two models do agree on a few things. A gloomy Sunday and Monday, and rain totals no more than 1.5 inches over the span of two days. Since the GFS is drier, it predicts warmer temperatures than the ECMWF. I am leaning more toward an earlier start for the rain, like the ECMWF model shows. Models have been consistent with themselves in terms of timing, but not with each other. Once the shorter range models begin to pick up on the system, we will get a much better idea.
For now, I'm keeping Sunday's temperatures in the upper 80s because if the rain does hold off until the afternoon, we have a good shot of 90 degree temps. After Sunday, high temperatures cool off slightly into the mid 80s. Rain chances for either Sunday or Monday will be adjusted once we become confident of the timing of the late weekend-early week system.