DOW radar studies of the mechanisms for tornadogenesis, maintenance, and dissipation

Case studies of tornadic storms have shown the importance of various sub-storm scale structures, including in updrafts/downdrafts and associated convergence/divergence regions in tornadogenesis and intensification.  But, the existence of the features alone is not sufficient for tornadogenesis.  The Doppler on Wheels (DOW) radars have collected dual-Doppler data in about 20 supercell storms, some tornadic, some non-tornadic, which allows for the characterization of these features using fine-scale resolution vector wind fields permitting structures, convergence/divergence, and vorticity to be diagnosed.  Moreover, approximately 10 of these dual-Doppler cases also have in situ instrumentation, which allows for characterization of the air masses surrounding tornadoes.  As part of the BEST (Boundary-layer Evolution and Structure of Tornadoes) project, during the 2024 tornado season, the DOWs collected an exemplary dual-Doppler data set near Duke, OK on May 23, 2024.  Seven-second dual-Doppler data and a 4.2 km baseline allowed for the temporal and spatial resolution of quickly evolving small-scale features associated with vertical velocity production.  The role of convergence boundaries in vertical vorticity production are identified as a tornado maintenance mechanism, and as these boundaries weaken and detach/move away from the tornado, dissipation occurs.  Ongoing inter-comparison efforts between the ~20 dual-Doppler cases at different stages of tornado evolution and exemplary case studies like Duke, OK, will be presented, and commonalities that contribute to tornado evolution will be discussed.