Evaluation of Convective Storm Attributes using Advanced Verification Techniques during HWT 2019

The Hazardous Weather Testbed (HWT) Spring Forecast Experiment is a collaborative project between the National Severe Storms Laboratory (NSSL), Storm Prediction Center, and the research community that investigates the predication of hazardous convective weather. Specifically, a variety of convection allowing models (CAMs) are evaluated daily and used as guidance for experimental forecasts. Recently, NCAR’s Research Applications Laboratory collaborated with NSSL and Atmospheric and Environmental Research (AER) to develop advanced verification techniques for use during the HWT 2019 experiment. These techniques were based on the enhanced Model Evaluation Tools (METplus) verification package system that is at the foundation of the Unified Forecasting System verification and diagnostic capability. The focus of the system was on storm attributes such as composite reflectivity, accumulated precipitation, environmental parameters, and hail.

Specifically, scorecards were created to assess multiple parameters in the CAMs out to 36 hours. Scorecards allow for a quick comparison of two different models with multiple statistics and significance thresholds. Categorical and neighborhood methods are displayed for composite reflectivity and accumulated precipitation, and continuous statistics for environmental parameters. In addition, three different methods to predict hail are evaluated using an object-based verification method from the Method for Object Based Diagnostic Evaluation (MODE). The output was displayed on performance diagrams and subjectively evaluated during the HWT Spring Experiment. This presentation will give results and lessons learned from these efforts.