An Assessment of Buoyancy and Baroclinity within Select VORTEX2 Storms

Over the course of the two-year Verification of the Origin of Rotation in Tornadoes Experiment 2 (VORTEX2), approximately 650 transportable “StickNet” probes were deployed near target thunderstorms. Most of the deployment strategies utilized in VORTEX2 favored the simultaneous sampling of two scales. A coarse array of probes (~30 km wide on average, ~3 km spacing) was deployed to sample heterogeneity on the storm scale, primarily tasked with an assessment of the thermodynamic deficits experienced within downdraft regions. Nested within this coarse array was a fine array (~5 km wide, ~1 km spacing) intended for the evaluation of thermodynamic and kinematic gradients very near low-level mesocyclones. As such gradients have been shown to be potentially critical in the evolution of pulses and overall buoyancy within the updraft, and the generation of baroclinic horizontal vorticity for parcels approaching the low-level mesocyclone, the composite depiction of the atmospheric state for tornadic and non-tornadic storms will be beneficial in this regard.

A subset of VORTEX2 cases has been chosen for study. Composites of virtual, density and equivalent potential temperature will be presented and related to the presence of tornadoes near the time of StickNet observation as well as the strength of low-level mesocyclones, as revealed by the suite of mobile Doppler radars observing these storms. One specific case from 18 May 2010, near and east of Dumas, TX, will be used as an example and treated more in depth.