I got a couple of torrential downpours back to back Sunday afternoon that put down over an inch of rain, then more rain last evening and early this morning that put down another inch or so. PIT airport got 0.39” on Sunday and 0.17” this morning, so that’s why I’m in the red and they’re in the yellow. I would guess UHI has some effect on thunderstorms, given that warmer temperatures create more instability, but that’s a conjecture and I’ve never looked at the science.