An Update on VORTEX-SE Activities at Texas Tech Univ.

We will detail analysis activities covering the first three seasons of the Verification of the Origin of Rotation in Tornadoes Experiment – Southeast (VORTEX-SE). During the spring seasons of 2016 and 2017, Texas Tech University deployed 24 StickNet probes across northern Alabama and southern Tennessee, both as part of a fixed 16-site “StesoNet” and as short-fused rapid deployments on targets of opportunity in individual intensive observing periods. We will show some of the results of this ongoing observational analysis, with particular attention paid to a tornadic QLCS that propagated through the array on 30 April 2017, where spatial heterogeneities in buoyancy were noted that discriminated the QLCS inflections from the remainder of the line, and further discriminated the tornadic and nontornadic inflections from each other. Other similar cases will be introduced.

This presentation will also discuss the results of ongoing investigation using ensemble sensitivity analysis (ESA) to better understand how heterogeneities in the inflow and storm-scale state influence the generation of low-level vertical vorticity in southeastern U.S. storms. The first set of analyses covers the central Alabama portion of the 27 April 2011 tornado outbreak, where the buoyancy in the base-state inflow and flanking downdrafts are identified as influential to the outcome in low-level vorticity. The influence of ancillary cells will also be explored using the same framework.

ESA has also been applied to the 15 April 2017 VORTEX-SE case, where tornado development was largely overforecast for the VORTEX-SE domain. This analysis will reveal mesoscale details that dictated the underproduction of low-level updraft rotation. In both of the above cases, specific recommendations will be put forward on best practices for targeted observation in future VORTEX-SE field campaigns.