I saw the same thing. In all fairness Koz, I believe the issue that affected us was not so much the rain itself, but the wind that accompanied that rain.
Unfortunately for Plummer, it appeared the rain blowing sideways occurred more when we were on offense, than when Pitt had the ball.
No science to support that assertion, but I recall watching the game, and I kept thinking the wind seemed to pick up when we went on offense.