Properties of Cold Pools Observed during the VORTEX-SE: Meso18-19 Field Campaign

From December 2018 through April 2019, an array of 24 Texas Tech University StickNet observing platforms (the “StesoNet”) observed the cold pools of numerous severe thunderstorms as part of the Meso18-19 phase of the VORTEX-SE (Verification of the Origins of Rotation in Tornadoes Experiment- Southeast) field campaign. The Meso18-19 StesoNet builds upon the array of 16 StickNet probes that collected data over the northern Alabama and Southern Tennessee region in 2016 and 2017. The goal of the StesoNet is to gather observations that help thermodynamically characterize convective cold pools that occur in the Southeastern U.S., increase our understanding of the dynamics that produce these cold pools, and assess differences that distinguish tornadic and nontornadic portions of these storms. This data collection is particularly motivated by recent numerical and observational studies that have continued to support the importance of baroclinic vorticity generation in low-level mesocyclone and tornado production.

Compared to previous seasons, there was a relative dearth of surface-based storms in the StesoNet domain through the project, limiting opportunities to associate cold pool buoyancy deficits with tornado occurrence, similar to the analysis carried out by these authors on a QLCS event from 2017. However, a tornadic event on 14 March 2019 does lend itself to this manner of examination. During this event, four tornadoes tracked within 15 km of a StickNet, and one of the tornadic supercells was observed by two StickNets, once well (~45 min) prior to tornadogenesis, and another immediately (~10 min) prior. The results from this event, as well as other Meso18-19 events, will provide insights into some of the factors that determine evolution from relatively benign storm modes into tornadic supercells. These findings will also help build upon the existing cold pool data already collected during VORTEX-SE and augment the results from past thermodynamic analyses.