Dual-Doppler analyses of the supercell that produced the Greensburg, KS tornado on 4 May 2007

During the evening (local time) of 4 May 2007, the first ever recorded EF-5 tornado made a direct hit on the town of Greensburg, KS just prior to 0300 UTC 5 May. Over an hour of nearly continuous data were collected on this storm by the mobile, polarimetric, X-band U-Mass Xpol radar. The longevity of this dataset is rare for a mobile radar-based tornado study, and allowed the radar to sample the parent storm during its initially cyclic tornadogenesis phase and its mature, long-lived tornado phase. The proximity of the U-Mass Xpol radar to the Dodge City, KS WSR-88D radar (KDDC) made it possible to synthesize a series of dual-Doppler analyses from 0130 – 0230 UTC every 10 minutes, except when the storm crossed the baseline between the two instruments around 0150. Three-dimensional storm structure and wind field evolution are examined from the analyses in order to illuminate the transition in the parent storm from the earlier cyclic-tornado phase to the long-lived, mature tornado phase, and to examine storm-scale processes associated with the intensification of the long-lived Greensburg tornado.