Synoptic environments and convective modes associated with significant tornadoes in the contiguous United States—a null case dataset

Higher resolution computer modeling and increasingly extensive observation networks have helped meteorologists improve forecasts of significant tornadoes over the past several years. Nevertheless, forecasters continue to rely on recognition of synoptic patterns and associated parameters. R.L. Thompson, J.S. Grams, and J.A. Prentice, through their work in Synoptic Environments and Convective Modes Associated with Significant Tornadoes in the Contiguous United States, have compared “rules of thumb” for significant tornado (EF-2+) forecasting using radar images and sounding-derived data including temperature, dew point temperature, wind speed and direction, and pressure at various levels of the atmosphere.

Understanding the atmospheric conditions leading to significant tornadoes is very beneficial, but knowing the differences between a tornadic and non-tornadic event is equally important. In this study, a null case dataset of significant severe weather has been produced. Over one thousand significant wind (65 kt.+) and hail (2”+) reports were collected, none of which were within 120km or 6 hours of a reported tornado. Interpolated RUC model analysis data were gathered for each report to extract the same parameters used in the previous research. This study will show statistical results for the significant wind and hail cases and compare them to the significant tornado dataset.