A Closer Look at Upper-Air Data and “TORFF” Events Observed During the Second Year of VORTEX-SE

In recent research, the authors have examined issues related to the threat posed by concurrent, collocated tornadoes and flash floods (referred to as TORFF events). These events pose many challenges from both a meteorological and communication standpoint.

This study presents an in-depth look at TORFF events that occurred during (or just outside) of the second year of the VORTEX-SE field project. A detailed look at the synoptic-to-mesoscale characteristics, radar patterns, precipitation accumulations, event timing, and the associated tornado and flood report details is presented. Care is given to classify each event in a similar manner to that presented for previously verified TORFF events in Nielsen et al. 2015 (WAF) and a more recent, “verified” list of TORFF events. Further, observed TORFF events will be placed in context with mobile soundings collected during the field phase of the second year of VORTEX-SE. Specific focus will be given to the ingredients associated with extreme precipitation and the environmental kinematic profile.

The results (as of this abstract writing) are largely consistent with the bulk meteorological characteristics of TORFF events identified in Nielsen et al. 2015. Specifically, the analysis of the confirmed TORFF events highlights very strong low-level shear, deep moisture, high surface relative humidity, and a stable nocturnal boundary layer as characteristics of TORFF events in the southeast. However, slight, but unique differences, do exist compared to other geographical regions around the country.