Monsoonal moisture from the southwest will combine with a slightly cooler air mass coming in from the north to bring a cool down to near 91 on Friday and that same temperature is likely on Saturday as well.
Lots of clouds will be around the Treasure Valley (especially Boise east) on Friday but there is not much of a chance of rain until later Friday night into the wee morning hours of Saturday.
If you see clouds in the valley on Saturday morning they should quickly move away leaving a sunny and seasonably nice day with lots of sunshine and a hot afternoon.
Sunshine continues on Sunday but it will be hotter with highs back to the mid to upper-90s.
Monday will be the hottest day in the extended forecast with temperatures likely topping 100 degrees again.
Then by mid-next week afternoon highs will drop to the mid-90s.
The central mountains will be partly cloudy on Friday with late night showers & storms that could last into the sunrise on Saturday.