Robust Observational Support of the Hypothesized Connection Between Rotating Updraft Width and Tornado Intensity

Our recent numerical modeling experiments have demonstrated a fundamental role of rotating updraft width in the regulation of tornado intensity. This is based on a very simple application of Kelvin’s circulation theorem. New analyses of observational datasets are providing strong support of these modeling results and theory. In this presentation, we will describe the generation of a pre-tornadic mesocyclone dataset derived from WSR-88D data, and then use it to show a robust linear relationship (R²=0.72) between pre-tornadic mesocyclone width and the EF rating of the corresponding tornado. Further analysis reveals that pre-tornadic mesocyclone width tends to be a persistent, relatively time-invariant characteristic, which ultimately makes it a better predictor of potential tornado intensity than pre-tornadic mesocyclone strength. We will also describe the generation of a dataset of “overshooting top” area (OTA) using GOES-16 Channel 14 longwave infrared data, as motivated by our model-based correlations between the mid-tropospheric convective updraft area and its cloud-top imprint. We use this dataset to show a robust linear relationship (R²=0.54) between the peak OTA and the EF rating of the corresponding tornado. It is noteworthy that both of these results apply to tornado events regardless of the season, geographic location, or even storm morphology of the event. In particular, this implies the potential applicability of our intensity-control ideas to tornadoes that develop within quasi-linear convective systems (QLCSs). This may depend on the mode of tornadogenesis within QLCSs, which, as we will argue, motivates critical field-observational and numerical-modeling needs.