AIRBORNE DOPPLER RADAR ANALYSIS OF SUPERCELLS DURING COPS-91

On 26 May 1991, NOAA P-3 airborne Doppler radar data were collected ne ar two tornadic supercells in the southern Plains during the Cooperati ve Oklahoma Profiler Studies (COPS-91) field program. The 3-cm radar m ounted in the tail of the aircraft was operated using the fore-aft sca nning technique (FAST). Both storms were sampled just minutes after ea ch had produced a tornado. The COPS-91 storms are the first tornadic s upercells to be sampled extensively by airborne Doppler radar using th e FAST methodology. Pseudo-dual-Doppler analyses of a dissipating stor m in southwest Kansas show no remaining low-level circulation, even th ough the storm had just produced a tornado. The analyses of a storm in northwest Oklahoma reveal better-defined features in the wind field n ear the surface. In contrast to what has been previously observed in p ost-tornadic supercells, the cyclonic vorticity in both storms was gre ater aloft than at low levels. The 26 May 1991 storms provide further evidence that supercells often contain multiple updrafts and mesocyclo nes. Cyclical mesocyclogenesis was occurring in the northwest Oklahoma storm while pseudo-dual-Doppler data were being collected. Airborne D oppler radar provides the potential for obtaining datasets throughout the lifetime of a storm at close range, where the observational geomet ry can be controlled to minimize known errors. The lessons learned fro m COPS-91 were incorporated into the airborne Doppler strategies emplo yed during the subsequent Verificafion of the Origins of Rotation in T ornadoes Experiment (1994-95).