Wednesday, 30 August 2023: 2:30 PM
Great Lakes BC (Hyatt Regency Minneapolis)
Ground-based, mobile and fixed-site rapid-scan radars have been used for the past fifteen years to study rapidly-evolving phenomena such as tornadoes in severe, convective storms. This talk will focus on data collected by the RaXPol (Rapid-scan, X-band, Polarimetric) radar at the University of Oklahoma, in which small anticyclonic tornadoes in a supercell in and near Selden, Kansas, on 24 May 2021, were probed. This storm also produced an EF-1 cyclonic tornado.
A summary of the formation and evolution of a predecessor, cyclonic tornado will be given, followed by a description of how and where the anticyclonic tornadoes/strong vortices formed and how they were related to the predecessor tornado. One of the anticyclonic tornadoes passed directly over RaXPol (Fig. 1) and formed when the southern edge of an apparent internal momentum surge interacted with the southern side of the rear-flank gust front (Fig. 2). In this presentation profiles of the azimuthal wind as a function of distance from the center and vertical variations will also be shown. Attempts to simulate the debris seen in a photograph taken when the tornado passed by will be given in a separate, poster presentation (Bodine et al. 2023).
The other anticyclonic tornado/vortex formed along the outer edge of the main, cyclonic tornado and was advected around by its circulation (Fig. 3). These unusual, small-scale, rapidly evolving features are particularly amenable to probing by rapid-scan radars and should be documented and studied further, especially when new, improved, electronically-scanning radars become available.
A summary of the formation and evolution of a predecessor, cyclonic tornado will be given, followed by a description of how and where the anticyclonic tornadoes/strong vortices formed and how they were related to the predecessor tornado. One of the anticyclonic tornadoes passed directly over RaXPol (Fig. 1) and formed when the southern edge of an apparent internal momentum surge interacted with the southern side of the rear-flank gust front (Fig. 2). In this presentation profiles of the azimuthal wind as a function of distance from the center and vertical variations will also be shown. Attempts to simulate the debris seen in a photograph taken when the tornado passed by will be given in a separate, poster presentation (Bodine et al. 2023).
The other anticyclonic tornado/vortex formed along the outer edge of the main, cyclonic tornado and was advected around by its circulation (Fig. 3). These unusual, small-scale, rapidly evolving features are particularly amenable to probing by rapid-scan radars and should be documented and studied further, especially when new, improved, electronically-scanning radars become available.
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