117 A Rare Tornado Merger Observed in the 24 May 2011 El Reno, Oklahoma, Supercell

Wednesday, 5 November 2014
Capitol Ballroom AB (Madison Concourse Hotel)
Michael M. French, NOAA/NSSL, Norman, OK; and P. Skinner, L. J. Wicker, and H. B. Bluestein

Unique observations of the merger of two tornadoes are documented using data from four radars, including one WSR-88D (KTLX), one polarimetric S-band radar (KOUN), and two phased-array radars: the multifunction phased-array radar (MPAR) and the Mobile Weather Radar, 2005 X-band Phased-Array (MWR-05XP). One of the tornadoes involved in the merger was an EF5 tornado and the other likely was a previously undocumented tornado; upon merging both the intensity and size of the resulting tornado increased a great amount. The formation of the second tornado is discussed using data from KTLX and KOUN and the merger process is discussed using the phased-array radar data. MWR-05XP electronic scanning in elevation allows for the merger process to be examined up through storm midlevels every ~10 s using PPIs and 3D isosurfaces of azimuthal wind shear. The similarities between this case and another tornado merger case also are discussed.
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