Thermodynamic and kinematic analysis of multiple RFD surges for the 24 June 2003 Manchester, SD cyclic tornadic supercell during Project ANSWERS 2003

During Project ANSWERS 2003 (Analysis of the Near-Surface Wind and Environment Along the Rear Flank of Supercells), mobile mesonet data (Straka et al. 1996) was collected on a cyclic tornadic supercell that tracked from near Woonsocket to Bryant, South Dakota. A large F4 tornado, one of the many tornadoes associated with this storm, destroyed the town of Manchester. The ANSWERS mesonet collected a rare observational dataset from within the RFD surge and along the RFD surge boundary in the early, mature and dissipating stages of the Manchester tornado. At times, the most forward part of the mesonet was within 1 – 1.5 km of the tornado. Thermodynamic analysis of the mobile mesonet time series indicates several RFD surge penetrations with an undilute thermodynamic signal within the surge. The perturbation equivalent potential (θ_e') and virtual potential (θ_v') temperatures showed a “warm” RFD signal consistent with those for significant tornadoes analyzed by Markowski et al. (2002). In addition to the research objective of characterizing the time evolution of a single RFD surge, another project goal included gathering and analyzing comparative thermodynamic and kinematic data for RFD surges within the same supercell that exhibits cyclic low-level mesocyclogenesis or cyclic tornadogenesis. The Manchester storm proved fruitful with the mesonet probing at least 5 RFD surges. Interestingly, these various RFD surges exhibited a variety of thermodynamic signals ranging from conditions similar to the storm inflow to cold RFDs with large θ_e and θ_v deficits. Extensive thermodynamic and kinematic analysis of the RFD surges for the Manchester storm will be presented.