M-20 B/C Ranger
Flight Crew Commercial; Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Rotorcraft
Flight Crew Last 90 Days 30; Flight Crew Total 1750; Flight Crew Type 950
Situational Awareness
Deviation - Altitude Excursion From Assigned Altitude; Deviation - Track / Heading All Types; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Weather / Turbulence; Inflight Event / Encounter Loss Of Aircraft Control
Air Traffic Control Provided Assistance; Flight Crew Took Evasive Action; Flight Crew Returned To Clearance
Human Factors; Weather
Was in cruise configuration with afternoon convective activity beginning. Had been in and out of a few clouds. Center advised of light to moderate rain ahead on my route of flight as I was penetrating clouds between two moderate rain signatures on the NEXRAD. The NEXRAD on my Garmin 510 showed the light to moderate rain as green and yellow signatures confirming the information given by Center. The image at the time of penetration was 3-4 minutes old. After penetration; we experienced convective activity and extreme lift making it impossible to hold altitude. Suddenly we had over 3;000 FPM registering on the VSI and hail hitting the windshield. I immediately did a 180 degree turn to the right and experienced a downdraft at 1200 fpm. I notified Center of the experience; conditions; the inability to hold altitude and evasive action taken. Center inquired if there was any noticeable structural damage and I replied none. Center then vectored us to the south of the convective activity with no further encounters during the remainder of the flight leg. When I viewed Flightaware to see what activity we flew through it showed green and yellow signatures. The following week when returning home; Flightaware showed a different picture with red; white and lightning signatures.
M20 pilot reported encountering hail and significant updrafts and downdrafts after Center advised of light to moderate rain as he was penetrating the clouds and had to reverse course to escape.  His NEXRAD images of the rain signatures matched what Center had advised of.