S206 'High Spatiotemporal Resolution Observations of the Dissipation of a Violent Tornado on 9 May 2016 Near Sulphur, Oklahoma'

Sunday, 6 January 2019
Hall 4 (Phoenix Convention Center - West and North Buildings)
Katherine E. McKeown, Stony Brook University, Stony Brook, NY; and M. M. French, H. B. Bluestein, and Z. B. Wienhoff

Mobile polarimetric X-band Doppler radar data obtained by the University of Oklahoma’s Rapid X-band Polarimetric radar (RaXPol) system are used to observe characteristics of a violent tornado during the end of its mature phase and dissipation phase; the tornado occurred on 9 May 2016 near Sulphur, OK. RaXPol’s high temporal resolution allows for volumetric data of the tornadic vortex signature (TVS) and tornado signature (TS) to be analyzed every ~20 s. One goal of this study is to examine in what manner the radar representation of the tornado dissipates in time and height. Recent studies have provided evidence that dissipation starts in the 1-2 km layer before dissipating at higher levels, and lastly near the surface, as a result of the TVS moving in different directions above and below this layer. However, owing to the difficulty in obtaining rapid-scan data of tornadoes, there have only been a handful of previous volumetric observations of tornado dissipation. We aim to add another case to this growing database, and to determine if dissipation of this tornado was consistent with that from previous studies.

Data were manually edited and de-aliased using Solo-ii, and were collected and recorded every ~2 s between the elevation angles of 0˚ and 10˚. These data were then interrogated to determine the vertical evolution of dissipation using different intensity thresholds to define a TVS/TS. In addition to the time-height dissipation, we also will discuss observed vertical discontinuities in the vortex structure, characterized by sudden large offsets in tornado location with height, and the unusually wide structure of the tornado.

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