Little Lehigh Creek Near Allentown
Little Lehigh Creek · Northeast · USGS gage 01451500
Trout (marginal) (summer mean 19.1°C — trout, warm in summer).
Water
66°F
Flow
39 cfs
Air
74°F
Sky
98%
Pressure
29.78 in
Wind
6 mph
Predicted hatches · 2026-08-03
PredictedSpotted / Summer CaddisHydropsyche spp.0.85
Predicted by conditions; no reports yet. water 18.9°C (66°F) sits in the prime band (14-19°C); peak season; 8 days sustained ≥12°C; heavy rain — blowout risk; watch evening, last hour of light.
flies: Elk Hair Caddis #14-16, Iris Caddis, X-Caddis
PredictedTricoTricorythodes spp.0.85
Predicted by conditions; no reports yet. water 18.9°C (66°F) sits in the prime band (16-21°C); peak season; 8 days sustained ≥15°C; heavy rain — blowout risk; watch early morning spinner falls.
flies: Trico Spinner #20-24, CDC Trico, Griffith's Gnat
PredictedHopper / TerrestrialsAcrididae (grasshoppers)0.85
Predicted by conditions; no reports yet. water 18.9°C (66°F) sits in the prime band (17-24°C); peak season; 8 days sustained ≥14°C; heavy rain — blowout risk; watch warm, breezy afternoons.
flies: Morrish Hopper #8-12, Chubby Chernobyl, Dave's Hopper
PredictedSlate Drake / IsonychiaIsonychia spp.0.42
Predicted by conditions; no reports yet. water 18.9°C (66°F) sits in the prime band (16-21°C); shoulder of the season; 8 days sustained ≥14°C; heavy rain — blowout risk; watch afternoon/evening; nymphs crawl to shore to emerge.
flies: Isonychia #10-12, Slate Drake, Leadwing Coachman
PredictedPale Morning DunEphemerella spp.0.30
water 18.9°C (66°F) is cooling past the prime band (13-18°C); shoulder of the season; 8 days sustained ≥12°C; heavy rain — blowout risk; watch late morning to early afternoon.
flies: PMD Comparadun #16-18, Sparkle Dun, Pheasant Tail #16
PREDICTED from the first-principles model only. Report-confirmed signal (fly-shop & forum reports) is the next milestone.