Date: 202108
Local time of day: 1201-1800
Location: ZZZ.ARTCC, US
Flight conditions: IMC
Weather elements / visibility: Thunderstorm
Light: Daylight
Aircraft: Small Aircraft; Low Wing; 1 Eng; Fixed Gear
Operator: Personal
Operating under: Part 91
Flight plan: IFR
Mission: Personal
Flight phase: Cruise
Airspace: Class E ZZZ
ATC / advisory: Center ZZZ
Reporter organization: Personal
Reporter function: Single Pilot; Pilot Flying
Reporter qualification: Flight Crew Instrument; Flight Crew Private
Human factors: Time Pressure; Workload; Communication Breakdown; Distraction; Situational Awareness
Anomaly: ATC Issue All Types; Deviation - Altitude Excursion From Assigned Altitude; Deviation - Speed All Types; Deviation / Discrepancy - Procedural Published Material / Policy; Inflight Event / Encounter Weather / Turbulence; Inflight Event / Encounter Loss Of Aircraft Control
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Took Evasive Action; Flight Crew Became Reoriented
Contributing factors: Weather; ATC Equipment / Nav Facility / Buildings
Primary problem: Weather

Narrative: During an IFR flight Date from ZZZ1 to ZZZ I encountered clouds and thunderstorms that were not forecast during the planned flight. The area of the thunderstorm was also not showing any data on my MFD XM weather display. I requested to climb from 15;000 ft. to 16;000 ft. expecting to be clear of the clouds; was cleared to 16;000 ft. The cloud tops were rising so requested and was cleared to 17;000 ft. The clouds were rising fast so I then requested lower and to deviate to the north to stay clear of the clouds. Was cleared to deviate as required; at or above 8;000 ft. What had been a broken layer of clouds was rapidly joining together and evident I could not fly below them either. I requested a report from ATC of what was ahead; the controller said all she had was light rain at my 11:00 but clear between our current location and ZZZ. I told ATC that it looked like a 'wall of water ahead of me; and could I get vectors to stay clear'. ATC said I could go direct to ZZZ and be clear of the rain. I turned direct ZZZ and almost immediately upon entering the cloud I encountered severe turbulence; reduced power to slow to 120; turned autopilot off; was attempting to hold attitude; airspeed; then altitude. We were clearly in an unexpected thunderstorm with severe downdrafts and updrafts that caused very erratic airspeed and altitude. There was severe static on the radio making communication difficult. Frequent lightning strikes was causing the static. I received some garbled and static filled transmissions from ATC to climb; which I acknowledged and attempted to comply with but was extremely busy trying to maintain control of the attitude and airspeed. Prior to getting clear of the thunderstorm the Center Controller handed me off to the Approach Controller; during this time communications were very hard to hear with the static; so I am not sure I received all instructions. Once I switched to the Approach Controller and was clear of the cloud; I got the weather at ZZZ and requested vectors for the RNAV Runway XX approach. ATC gave vectors to final with minimum altitude that was 3;000 feet high; ATC had me change to ZZZ Tower. I told tower I was too high so they approved making a 360 degree turn to loose altitude and cleared to land. Balance of the flight was uneventful.I understand the Center radar has a delay so it would be good to be reminded of that before accepting a vector for weather or trust there is not a thunderstorm.




Synopsis: Single Engine pilot on an IFR flight plan encountered unforecasted weather containing a thunderstorm and severe turbulence. Maintaining airspeed; altitude and communication with ATC was difficult and an altitude deviation may have occurred.