In a terminal operation hampered by turbulence; thunderstorms; rain and hail; a PA46 pilot suffered an NMAC with a twin Cessna near touchdown.

Narrative

I was on an IFR flight plan. Airport was reporting visual approaches. The weather in the area was active with thunderstorms. When I was directed to continue my descent from 14;000 FT to 11;000 FT my onboard radar was showing heavy precipitation directly ahead. I was not willing to continue into that weather and requested to stay up at 14;000 FT to get a better look at my options. I found an area about 10 miles northeast of the airport to circle in the clear to see what might work to get in. After about 15 minutes I felt I could make a VFR approach to the airport and told Center I would like to cancel IFR and go VFR. I called the Tower to tell them I was 8.9 out northeast and wanted to do a full stop landing. They cleared me to land on runway. During the descent I ran into very heavy rain and extreme turbulence. When I was about 50 feet from touch down I was directed to go around. I was later told that I had overtaken a twin Cessna and was about to land on top of that plane. Radio communication was difficult because of the rain and possibly some hail noise along with the turbulence. I never heard the Tower talking to the other plane. Obviously I was able to stop my descent and do a go around successfully.