Small Aircraft; Low Wing; 1 Eng; Retractable Gear
Flight Crew Instrument; Flight Crew Private
Flight Crew Last 90 Days 15; Flight Crew Total 2100; Flight Crew Type 1700
Deviation - Altitude Excursion From Assigned Altitude; Deviation - Altitude Overshoot; Deviation / Discrepancy - Procedural Clearance; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence
Human Factors; Weather
After flying for approximately one hour; ATC on several occasions would attempt to send me through a line of severe thunderstorms. I was given the approval for deviations as needed to avoid build ups. At one point I requested to fly from my position to ZZZ and was granted permission to go direct ZZZ. Before arrival at ZZZ I was given direct to an intersection (I believe ZZZZZ) but cannot recall. That vector took me through an area of severe turbulence that caused the airplane to pitch up and climb rapidly. To avoid damage to the aircraft I disengaged the auto pilot and altitude hold. At some point a downdraft started a rapid descent that seemed to be several thousand feet per minute; I can't be sure. I had to fight to maintain control of the aircraft. Looking at the flight path and radar; I believe the turbulence was near ZZZZZ1 intersection. I believe just prior to this event; I had been instructed to descend from my current altitude to 4000 ft. and was in the process of doing so when the turbulence occurred. When I finally cleared the violent weather; a very nice controller from [Center] called and asked my assigned altitude and I replied 4000 ft. When he called I checked my altitude; I was at 3200-3300 ft. Either I had not recovered or the Altitude hold had kicked off as I recall. As I said; the controller was very nice and did not seem to have an issue; but I felt I should report this incident. No one was hurt; and to the best of my knowledge there were no other planes in the area. Looking back over my flight path you can see this occurred ESE (East South East) of ZZZZZ1.
GA pilot reported severe turbulence.