Crestline Soaring Society

High pressure and humid, but only 99F instead of 105F in the valley early afternoon. Good cycles while I set up the US 166. Few pilots - CSS group at Yosemite. Saw a PG going up like a rocket over the western draw as I put my harness on, so I hurried and got to launch, which was 'active' and crossing a bit from the right. Launched at 15:30 and banked and got over the draw and there it was. Circled right up, through a courteous tandem, to 3700 or so as it drifted toward Marshall. Eventually I realized there was a mild inversion around 4100-4200 that was stopping the weaker thermals. I kept circling in these things that would jump around and disappear. Over at Regionals I found a 600 FMP core and worked it under an Xtralite, busting through 4200 and on up to 5300. I turned and flew min sink to Crestline in 150-200 down. As I got near the eastern house thermal (hillside) I hit 500 FPM down. I was at 4850, so I turned around and crept out to Regionals. Still the same out there, except the drift of the thermals got more and more west to east, and faster. Did a few rounds of thermalling up from Regionals or Last Chance and drifting to S of Marshall, then flying upwind and doing it again. The lift was weakening a bit and I still had the hike to the 750 for my truck to do, so I landed into SW 10 at 17:12.