One of the best hatches in Pennsylvania has to be the Sulphur. There are two variations Ephemerella invaria and Ephemerella dorthea .
Many times the hatch will trickle until the last moments of dusk then explode with numbers unimaginable. If you catch it right it could very well be one of the heaviest hatches you’ll witness through the spring season. As with most hatches, feeding activity starts way before the visually apparent top water rises. I enjoy the nymph action hours before evening. Nymphing techniques can often be sloppy yet still productive due to the naturals preparing for the evening dash to the surface. My latest favorite nymph pattern consists of the following (Don’t be afraid to tie it in larger sizes for high water and heavily stained conditions).
Tail: dark partridge
Abdomen: dark possum with SLF blend
Rib: very fine dark copper
Thorax: hares ear, possum, SLF blend
Wing case: black thin skin
And the table of controlled chaos (Where did I put those feathers…)