The Unusual Evolution of the Entire Life of a Tornadic Supercell in South-Central Kansas and North-Central Oklahoma on 14 May 2018

The evolution of a tornadic supercell is described based on radar data collected from near first echo, by RaXPol, a mobile, X-band, rapid-scan, polarimetric Doppler radar. This dataset is unique in that it captured the evolution of a tornadic supercell from just after first echo nearly continuously, for two hours, from almost the same location. It thus provided the unusual opportunity to analyze the process of the evolution of an ordinary cell/multicell storm into a supercell using real data. Tornadogenesis is also analyzed. During data collection, an “Owl horn” echo was observed, along with other vortices along the flanks of the storm at midlevels. To the best of our knowledge, this is the first time that the rotational characteristics of these types of vortices have been documented by Doppler radar. Our single Doppler analyses are complemented by a time-lapse video of the wall cloud/cloud base just prior to tornadogenesis. Large hail was also reported.

The latter portion of the life of the storm was documented by WSR-88D radar data. This portion of the life history of the storm was extremely unusual in that although it had been propagating to the southeast, it came to a grinding halt and retrograded back to the north after dark, spawned another tornado in Kansas, and finally collided with a QLCS having a TVS at the leading edge of its gust front. The question of why the storm retrograded after dark will be examined.