I live in Warren and flyfish that section of the river fairly often. I will NOT wade the river in any outflow over 1800 cfs. It is 2400 cfs right now. Everyone has a different idea of what is safe flow for wading, for me, its 1800 or below. I'm 24, exercise regularly, and I feel that the river is just plain unsafe over 1800, but you know your limitations and comfort zone best. The army corp of engineers does a daily lake and river info recording you can hear if you call 814-726-0164. the recording is done in the morning around 8AM, so depending on when you call the river may be higher or lower. The river has been a steady 2200-2400 cfs for a few weeks now, but it may be raised depending on how much rain/snow we get this weekend.
I've had the most consistent success in the river on bead headed nymphs, prince or flash back GRHE, but these seem to produce best during the warmer months. Early season and late season I switch to streamers. In march and April I've done fairly well on a mixed bag of walleye and brown trout fishing orange and white clousers, and orange tiger barred zonker flies. My absolute favorite fly for the river is a black wooly bugger with rubber legs and a set of barbell eyes. I tie them on a size 4 saltwater hook. A few years ago I got a brown that was 27 inches on that fly by the observation area on the route 59 side. It also accounted for my two best trout of this summer out of the river, a rainbow and brown, caught within 15 minutes of each other. While a prince may account for more fish, the scattered big fish on the wooly bugger are what the river is about to me.
I fished the river at the tailwaters briefly on my way home from Kinzua Creek 2 weeks or so ago. I caught 3 rainbow trout all about 13 inches on a white wooly bugger. Probably last year or the year before's stocked parr.
Allegheny River Walleye, caught on a orange and white clouser
trout from the allegheny, taken on a black, rubber legged wooly bugger