Identifying Common Traits for Squall Line Tornadoes in the Ohio Valley

A particularly common occurrence in the Ohio Valley, quasi-linear convective systems (QLCSs) can quickly produce brief, spin-up tornadoes that present a significant challenge to operational meteorologists. Recent research in the National Weather Service has led to the development of the three-ingredients method (3IM), a technique that identifies various radar features, also known as confidence builders or nudgers, that indicate an increased likelihood of tornadogenesis in a QLCS if present. Although the 3IM has already proven to be a successful R2O effort, it is of interest to our group to investigate if there are patterns in a given mesoscale environment that would favor development of a certain feature, giving the opportunity of extra lead time to forecasters. To conduct this investigation, a catalog was created of all QLCS tornadoes from Indiana, Kentucky, and Tennessee from 2017-2023. Within this database, the presence of two particular features that are most commonly observed in the Ohio Valley was noted, namely the front-end nub and the line break. For each front-end nub and line break case, the SPC 40-km Mesoanalysis tool was used to record the values of 24 environmental parameters for the mesoscale environment near tornado touchdown. Plotting and analysis of these values revealed patterns in the environment that could suggest the development of a particular radar feature over the other. For example, an environment with higher values of CAPE appears to be strongly associated with front-end nub cases while higher values of SRH (above 400 m^2/s^2) almost always correspond with the development of line breaks. This same comparison will be implemented in the future on other confidence builders and nudgers with results being shared with operational forecasters in the Ohio Valley region.