Rapid-scan analyses of the Goshen County tornado during VORTEX-2 using a mobile, phased-array, X-band, Doppler radar

In 2009-2010 during VORTEX-2, a mobile, phased-array, X-band Doppler radar (the MWR-05XP) was used to obtain several datasets of tornadic supercells. The MWR-05XP scans electronically in elevation while the antenna scans mechanically in azimuth so that, at a given azimuth, data at all elevation angles are being obtained at almost the same time. As a result, data collected by the MWR-05XP can be used to investigate the short time scale, vertical evolution of tornadoes without correcting for storm motion or invoking steady state assumptions. On 5 June 2009, during year one of VORTEX-2, the MWR-05XP scanned a supercell in Goshen County, WY during the entirety of a tornado. Volume scans up to 20⁰ in elevation angle were obtained every ~7 sec. In addition, the MWR-05XP scanned tornadoes in 2010, during year two of VORTEX-2, on 10 May, 19 May, and 25 May. Volume scans up to 40⁰ in elevation angle were collected every ~6-15 sec. The focus of the talk will be on the evolution of the TVS signature in the 5 June 2009 tornado over a ~30 min period. From ~2200-2230 UTC, ~3200 observations of the TVS signature at different heights were obtained. Topics of discussion will include unique observations of: 1) rapid, height-dependent tornado weakening/dissipation and re-strengthening/regeneration at midlevels, 2) vertically coherent, regular oscillations in TVS strength at higher elevation angles, 3) the vertical orientation of the tornado, and 4) the process of tornado decay. Tornado data obtained in 2010 also may be discussed for comparative purposes, time permitting, as they relate to the topics listed above.