Thunderstorms were in the vicinity, but the pilot elected to continue the approach. During a turbulent encounter on short final, the airplane was turned 30 degrees to the right of runway heading and the nose was forced upward. The pilot regained control of the airplane and landed firmly on the runway surface. The airplane departed the left side of the runway, the left wing “dug” into the grass surface, cartwheeled and came to rest inverted. Witnesses observed the wind shift from a right quartering head wind to a right quartering tailwind while the airplane was on short final.
