The pilot reported that prior to takeoff, he noted an approaching storm but estimated that the wind was light and variable for the takeoff roll. The airplane was slow to accelerate and reached the 50 knot rotation speed halfway down the runway. The pilot stated that the airplane lifted off and maintained an altitude a few feet above the runway, but lost altitude at the end. The airplane struck the ground and subsequently nosed over, coming to rest inverted. A few minutes after the accident, the pilot reported that it began to rain. The airport density altitude at the time of the accident was calculated to be approximately 9,000 feet, which is 1,000 feet above the manufacturers recommended maximum takeoff altitude as outlined in the Pilot's Operating Handbook. The weather observation facility located on the field reported that 3 minutes before the accident the wind was a left quartering tailwind at 5 knots, while shortly after the accident the wind was a left quartering tailwind at 22 knots, gusting to 32 knots with respect to the airplane's takeoff runway direction. The pilot reported that there were no preimpact mechanical malfunctions or failures with the airframe or engine that would have precluded normal flight.