South Branch Au Sable River Near Luzerne
South Branch Au Sable River · Driftless / Midwest · USGS gage 04135700
Trout (marginal) (summer mean 18.6°C — trout, warm in summer).
Water
59°F
Flow
193 cfs
Air
56°F
Sky
100%
Pressure
30.02 in
Wind
13 mph
Predicted hatches · 2026-09-15
PredictedSpotted / Summer CaddisHydropsyche spp.0.50
Predicted by conditions; no reports yet. water 14.8°C (59°F) sits in the prime band (14-19°C); shoulder of the season; 8 days sustained ≥12°C; watch evening, last hour of light.
flies: Elk Hair Caddis #14-16, Iris Caddis, X-Caddis
PredictedSlate Drake / IsonychiaIsonychia spp.0.40
Predicted by conditions; no reports yet. water 14.8°C (59°F) is warming toward the prime band (16-21°C); peak season; 8 days sustained ≥14°C; watch afternoon/evening; nymphs crawl to shore to emerge.
flies: Isonychia #10-12, Slate Drake, Leadwing Coachman
PREDICTED from the first-principles model only. Report-confirmed signal (fly-shop & forum reports) is the next milestone.