Evaluating hail diagnosis techniques using high resolution verification

During the summers of 2006, 2007 and 2008, the National Severe Storms Laboratory conducted high resolution verification efforts on numerous severe weather events across the U.S. This project was originally called the Severe Hail Verification Experiment (SHAVE), with the name later changed to the Severe Hazards Analysis and Verification Experiment (SHAVE) to reflect differences in how the experiment was conducted. During all three years, the primary goal of SHAVE was to collect hail reports at higher resolution than what is available through Storm Data. This study will evaluate the performance of several hail diagnosis techniques. These techniques include a hail diagnosis algorithm which utilizes several radar reflectivity and velocity based parameters together with environmental data in the vicinity of a storm, and multi-radar, multi-sensor hail diagnosis grids. Results using SHAVE reports will be compared to results using Storm Data to assess whether differences in algorithm skill result from differences in verification data resolution. Also, variations in near-storm environment and storm structure will be compared for several cases.