The Pretornadic and Tornadogenesis Phases of the 12 May 2010 Supercell of Clinton, Oklahoma, Intercepted by Vortex2
Open Access
Author:
Hatlee, Timothy Patrick
Graduate Program:
Meteorology
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
April 03, 2012
Committee Members:
Yvette Pamela Richardson, Thesis Advisor/Co-Advisor Paul Markowski, Thesis Advisor/Co-Advisor Jerry Y Harrington, Thesis Advisor/Co-Advisor
Keywords:
VORTEX2 supercell tornado DRC
Abstract:
The pretornadic and tornadogenesis phases of the 12 May 2010 supercell in Clinton, Oklahoma, intercepted by the second Verification of the Origins of Rotation in Tornadoes Experiment (VORTEX2) are analyzed. This analysis relies on radar data from the WSR-88D in Frederick, Oklahoma (KFDR), and a pair of Doppler-on-Wheels (DOW) radars, mobile mesonet observations, and mobile sounding observations.
The storm features two periods of intensification of low-level rotation, the second of which leads up to tornadogenesis at 0138 UTC. The peak intensification of this first time period directly precedes the formation and descent to low levels of a descending reflectivity core (DRC), similar to those that have been documented in recent studies of supercells. The second period of intensification occurs directly after the DRC reaches low levels. The dissipation of a pre-existing low-level rotation, and the formation and subsequent intensification of a new low-level rotation may be associated with the descent and arrival at low levels of the DRC.
Angular momentum (and circulation) rapidly increases after the arrival of the DRC at low levels, reaching a maximum value at the time of tornadogenesis. The amount of circulation within a 2 km-radius ring surrounding the low-level vertical vorticity maximum compares favorably to that of previously observed tornadic supercells.
