Narrative:

I was flying single pilot and was the only soul on board the king air 200. I was en route when I encountered a severe thunderstorm. Preflight weather did not depict the storm. I did see several other thunderstorms in the area; but did not believe them to be moving into my planned route of flight. I asked for and was granted deviations south of course when I came upon the first cell. As I 'rounded the corner' of the first storm I found myself face to face with a super-cell. I immediately made a course reversal and advised ATC that I would be doing so. I had already descended through 10;000 ft MSL on my way to the assigned 9;000 ft MSL. Upon making the turn I encountered a severe updraft and was unable to continue descending. When I rolled out my new heading; my altitude had increased to 10;400 ft MSL; and altitude that I had already vacated. I recovered on my new heading and leveled off at 9;000 ft MSL. I diverted to a nearby airport and waited for the weather to improve. In the future I will be more aware of high-risk weather conditions. I will also be aware that my onboard weather radar might not be telling the whole story (i.e. The first storm casted a radar 'shadow' and did not paint the larger storm behind it). Another resource available to me that I should have used (and will in the future) was san angelo radio (flight service). They would have been able to warn me of adverse conditions giving me; more time to find a better way around the storms. Other contributing factors were 'get there itis' because this was my third leg of the day and because I felt lower risk because I did not have passengers onboard. The risk of flirting with thunderstorms is not worth arriving on time.

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Original NASA ASRS Text

Title: A BE20 pilot encountered unanticipated severe weather masked on his radar by an intermediate cells and while taking evasive action temporarily lost control in an extreme updraft. The pilot diverted and waited for the weather to move on.

Narrative: I was flying single pilot and was the only soul on board the King Air 200. I was en route when I encountered a severe thunderstorm. Preflight weather did not depict the storm. I did see several other thunderstorms in the area; but did not believe them to be moving into my planned route of flight. I asked for and was granted deviations south of course when I came upon the first cell. As I 'rounded the corner' of the first storm I found myself face to face with a super-cell. I immediately made a course reversal and advised ATC that I would be doing so. I had already descended through 10;000 FT MSL on my way to the assigned 9;000 FT MSL. Upon making the turn I encountered a severe updraft and was unable to continue descending. When I rolled out my new heading; my altitude had increased to 10;400 FT MSL; and altitude that I had already vacated. I recovered on my new heading and leveled off at 9;000 FT MSL. I diverted to a nearby airport and waited for the weather to improve. In the future I will be more aware of high-risk weather conditions. I will also be aware that my onboard weather radar might not be telling the whole story (i.e. the first storm casted a radar 'shadow' and did not paint the larger storm behind it). Another resource available to me that I should have used (and will in the future) was San Angelo Radio (flight service). They would have been able to warn me of adverse conditions giving me; more time to find a better way around the storms. Other contributing factors were 'get there itis' because this was my third leg of the day and because I felt lower risk because I did not have passengers onboard. The risk of flirting with thunderstorms is not worth arriving on time.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.