Mud plugs caused by thunderstorms on Yellowstone Park (Yellowstone itself, Lamar, and Soda Butte) on 4th of July weekend is clearing up nicely!! Though I wouldn't put my boat in today (not my color - see below) for the maximum dry-fly experience, one can move some fish with nymphing rigs. It should go back to normal = before the mud plugs = by the weekend.
"Good Green" is the keyword whenever fishing the Yellowstone. Luckily I worked for and was trained by a few of the most knowledgeable and longest outfitters in the area. Thanks to them, I was able to attain "the perception" and read "the temperament" of the River so quickly during the first few seasons of my career.
Miscellaneous species of caddis and mayflies are hatching through out the day.
Keyword for me and my clients this season is: A single dry-fly.
Water level is dropping daily. Watch for submerged rocks, if you are floating.