Madison River
Upper

Flows/Temperatures (as of August 27th; click the name for real-time numbers)
Hebgen Outflow - 760 CFS

Kirby - 875 CFS
Kirby High/Low Temps - 69/57F

Cameron - 971 CFS
Cameron High/Low Temps - 66/59 F

The Weeks Weather Forecast in the Valley

Upper Madison
The Upper Madison is generally in similar shape as last week. The sustained mid-80s weather has made fishing a bit more challenging though. Just like earlier in the summer, fishing is best in the mornings and evenings, with small windows of productivity sprinkled throughout the day. With lower flows coming out of the dam, fish are concentrated within deeper pockets and faster moving water to find refuge from the sun. Rain and cloud cover are on the way (expected to arrive this weekend), so all of that will probably change as the water cools off!
Dry fly fishing is on and off throughout the day, with fish rising for spinners intermittently and some can be coaxed up with a small ant or beetle, especially in the riffles.
On the nymphing side of things, small mayfly-ish emergers in olive or brown are by far the most productive genre right now, with olive and red perdigons taking second place.

Dry Flies - Winna Spinna, Carnage Hopper, Arricks Flying Ant, Parachute Adams
Nymphs - Olive Hot Spot, Mayday Mayfly, BBQ Baetis, Red Neck

Flows/Temperatures (as of August 13th; click the name for real-time numbers)
Hebgen Outflow - 760 CFS

Kirby - 886 CFS
Kirby High/Low Temps - 67/55F

Cameron - 983 CFS
Cameron High/Low Temps - 68/59 F

Upper Madison
The Upper Madison has been in great shape recently. That colder week really helped add some more energy into the river, and fishing has been a lot more productive with those lower water temps. I had a great day out in the float section on Tuesday, and the walk/wade section has been fishing steadily as well. The usual mid-day lull is still there, but only for an hour or two. They have dropped flows coming out of Hebgen, so focus on deeper slicks and riffles farther away rather than the bank.
A hopper dropper setup is the most productive right now, because they truly are hitting both. Little mayfly attractors like a Parachute Adams have been good in the mornings, and smaller hoppers/attractors or ants have been working great in the afternoon. Subsurface, emergers and perdigons are quite productive, especially in darker colors or green.

Dry Flies - Chili Dog, Bionic Ant, Bogus Beetle, Carnage Hopper
Nymphs - Olive Hot Spot, Full Metal Jacket, BBQ Baetis

Flows/Temperatures (as of August 13th; click the name for real-time numbers)
Hebgen Outflow - 853 CFS

Kirby - 976 CFS
Kirby High/Low Temps - 62/58 F

Cameron - 1,090 CFS
Cameron High/Low Temps - 61/58 F

Upper Madison
The rain and cooler weather I've been anticipating arrived Wednesday afternoon, and as the water temperatures show, we're in for a big change in how the Madison is fishing. As you could have guessed, the dry fly bite has slowed quite a bit since temps dropped, but you can still find fish looking up in between rain showers, mainly in the little slicks and flats. Sub-surface approaches are by far the most productive fishing right now, both with a nymph rig or streamer. Swinging a smaller leech or stripping a larger sparkly pattern through runs will be a great way to entice a fish as this cooler weather persists. Nymphing small, darker flies was quite productive for me before this rain rolled in, and that should continue as long as the water stays relatively clear and at a similar level.

Dry Flies - Chili Dog, Arricks Ant, Bogus Beetle, Royal Chubby
Nymphs - Red Neck, Olive Hot Spot, Full Metal Jacket, Two Bit Hooker
Streamers - Crystal Bugger, Sparkle Minnow