The author is grateful to H. Brooks, C. Doswell, E. Rasmussen, T. Shepherd, I. Watson, and C. Ziegler (NSSL), for assistance and enlightening discussions on this research. The author also benefited from comments by the two reviewers and conversations with D. Dowell, S. Weygandt, and J. Wurman (University of Oklahoma). R. Davies-Jones (NSSL) is recognized for suggesting and helping interpret the swirl ratio calculations and also serving as the author’s mentor while a National Research Council–NOAA Postdoctoral Research Associate. Funding and support for VORTEX field operations were provided by NOAA/NSSL, Center for the Analysis and Prediction of Storms at the University of Oklahoma (NSF ATM 912-0009), and the Graduate College at the University of Oklahoma.
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