Processes Contributing to Tornadogenesis Failure in the 26 May 2010 Supercell near Prospect Valley, CO
Open Access
- Author:
- Murdzek, Shawn
- Graduate Program:
- Meteorology
- Degree:
- Master of Science
- Document Type:
- Master Thesis
- Date of Defense:
- March 20, 2019
- Committee Members:
- Paul Markowski, Thesis Advisor/Co-Advisor
Yvette Pamela Richardson, Thesis Advisor/Co-Advisor
Matthew Robert Kumjian, Committee Member - Keywords:
- supercell dynamics
VORTEX2
supercell thunderstorms
observational case study
tornadogenesis failure - Abstract:
- A nontornadic supercell that produced multiple nearly-tornadic vortices was intercepted by the Second Verification of the Origins of Rotation in Tornadoes Experiment on 26 May 2010. Using observations from dual-Doppler mobile radars, a five-probe mobile mesonet, and a proximity sounding, factors that prevented these vortices from strengthening into tornadoes are examined. Mobile mesonet observations indicate that the supercell possessed outflow with excessive negative buoyancy, likely owing in part to low boundary-layer relative humidity as indicated by a high environmental lifted condensation level. The circulation about the mesocyclone at 0.6 km above ground level (AGL) is found to be weaker than that of a previously studied tornadic storm. Trajectories suggest that the lesser circulation at 0.6 km AGL is due to the low-level mesocyclone ingesting considerable crosswise vorticity from the near-storm environment, which results in a more disorganized low-level mesocyclone, and the inability for parcels rich in streamwise vorticity to reach the low-level mesocyclone. Dual-Doppler wind and mobile mesonet observations also show the presence of a strong, warm downdraft south of the low-level mesocyclone. This downdraft may have prevented parcels rich in streamwise vorticity from the forward flank from reaching the low-level mesocyclone, and also caused the rear-flank gust front to surge well eastward, removing the low-level mesocyclone from the inflow air. Owing to the potential role of the warm downdraft in tornadogenesis failure, it is suggested that future research explore the prevalence and formation mechanisms of such downdrafts.