May 23 - July 29
Examining the Potential of ZDR Columns to Predict Tornado Formation and Intensity in Quasi-Linear Convective Systems
Kyndra Buglione (Montana State University - Bozeman), Dr. David Bodine (OU/ARRC), Rachael Cross (OU/ARRC & OU/SoM), and Morgan Schneider (OU/SoM)
What is already known:
- Lead times on tornado warnings are shorter for quasi-linear convective systems (QLCSs) than for supercells
- QLCSs generally produce weaker and more transient tornados, but their night time occurrence makes it difficult for spotters and forecasters
- Updraft width, height and area can be an indicator of tornado intensity in supercells
- ZDR columns can be used as a proxy for updraft characteristics to predict the formation and intensity of tornadoes in supercells
What this study adds:
- This study investigates the heights and widths of tornadic and nontornadic ZDR columns in 54 QLCS mesocyclones.
- The widths of ZDR columns associated with tornadic mesovorticies were slightly larger than those associated with nontornadic mesovorticies.
- With future research, the width of a ZDR column could potentially help forecasters predict tornado formation in QLCSs.
- The heights of ZDR columns associated with tornadic mesovorticies were not a good indication of tornado formation and intensity.
Abstract:
Although the warning performance for supercell tornadoes has greatly improved, it is generally less adequate for quasi-linear convective systems (QLCSs). Recent studies have demonstrated that differential reflectivity (ZDR) columns can be used as a proxy for updraft intensity and may help anticipate tornado formation within supercells. This study analyzes ZDR column in 54 QLCS mesovortices to further investigate their potential to indicate tornado formation and intensity within QLCSs. A series of ZDR column cases associated with both tornadic and nontornadic mesovorticies were studied by quantifying the height and width of each column at multiple instances prior to tornadogenesis. When comparing the width of the ZDR columns between tornadic and nontornadic cases, the tornadic ZDR column were slightly wider on average than the nontornadic ZDR columns. More studies with a larger sample size and more statistical analysis are needed to verify this correlation. However, the initial results indicate that the width of the ZDR column could potentially be useful to forecasters when predicting tornadoes in QLCSs, especially when paired with other polarimetric radar signatures. Comparing the height of the ZDR columns for tornadic and nontornadic cases, there was not a distinguishable difference between tornadic and nontornadic cases or different intensities. Although most of the correlations were not incredibly consistent across all the ZDR column cases, the initial results show somewhat promising correlations when looking at the ZDR column width as an precursor to tornado formation and should be studied further in future research.