Surface Cold Pool Observations near Tornadic and Nontornadic QLCS Mesovortices during PERiLS Monthly Weather Review

Past studies have shown baroclinic zones between warm ambient inflow and cooled downdraft air to be key in the generation of horizontal vorticity and in potential tornadogenesis if tilted and stretched in the vertical by updrafts. While previous work has focused on Great Plains supercells, a much narrower body of work has considered similar vorticity sources in high-shear, low-CAPE supercells and quasi-linear convective systems (QLCSs). In this study, 166 Texas Tech University StickNet cold pool observations from the Propagation, Evolution, and Rotation in Linear Storms (PERiLS) field campaign, including 76 mesovortex (23 tornadic and 53 nontornadic) and 35 high-shear, low-CAPE supercell intercepts, are statistically and spatiotemporally analyzed. Larger virtual potential temperature gradients were observed near rotating segments of the QLCS. No statistically significant differences in cold pool characteristics are evident globally between nontornadic and tornadic mesovortices, though significant differences do exist when considering specific periods of the mesovortex life cycle and mesovortex-relative position. Three fine-scale array (∼1-km spacing) mesovortex intercepts during the nontornadic, time-of-tornado, and posttornadic phases support the statistical analysis, possibly implicating baroclinic vorticity generation as a viable source of vorticity to achieve tornadogenesis within QLCS mesovortices. Further, this study found supercells in high-shear, low-CAPE regimes uniformly have weaker cold pools than supercells in larger CAPE environments. After QLCS–supercell mergers, the resultant QLCS cold pool tended to weaken immediately downstream of the merger but with no disruption in the tornado potential of the QLCS segment. Grant no. NA20OAR4590455 Grant no. NA21OAR4590151