The pilot reported that, during the initial climb following a takeoff from runway 20, the airplane encountered an abrupt, unanticipated wind shift. The airplane was unable to gain altitude during the initial climb and the pilot elected to land the airplane on the remaining runway. During the landing, the airplane touched down with its landing gear retracted, overran the departure end of the runway, and came to rest in a grassy area. The airplane sustained substantial damage to the fuselage during the accident. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. The surface weather observation reported at the airport about 5 minutes before the accident included wind from 200° at 12 knots, gusting to 18 knots, with thunderstorms noted in the vicinity and a remark of distant lightning from the west to northeast quadrants. The pilot stated that he was aware of the wind conditions and that during taxi he noted that the windsock validated the direction/speed. He also reported that it started to rain as he lined up on the runway for the takeoff. The weather conditions reported about 15 minutes after the accident included variable wind direction at a velocity of 5 knots with gusts to 28 knots, a visibility of ½ statute mile in heavy rain and thunderstorms, with lighting present in all quadrants. These weather observations surrounding the accident time were indicative of changing weather conditions associated with convective weather activity, which could include sudden wind shifts.