A Multi-Year Performance Evaluation of NSSL’s Warn-on-Forecast System Using Scorecards

The NOAA National Severe Storms Laboratory’s (NSSL) Warn-on-Forecast System (WoFS) has been run in real-time on selected days over targeted regions since 2017. The WoFS domain is centered over area where severe weather and/or flash flooding risks are forecasted by the Storm Prediction Center’s (SPC) Day 1 convective outlook and the Weather Prediction Center’s (WPC) Day 1 Excessive Rainfall Outlook, respectively. This study compares ensemble probabilistic model guidance from WoFS against a four-member, time-lagged ensemble from the High-Resolution Rapid Refresh model (HRRR-TLE) and the High Resolution Ensemble Forecast system (HREF). The study includes real-time runs from 2018-2022 as part of the annual Hazardous Weather Testbed Spring Forecasting Experiment and real-time runs from 2018-2020 as part of the collaborations with the Weather Prediction Center. Fields evaluated using the scorecard include composite reflectivity, low level reflectivity, low and mid-level updraft helicity, and precipitation. Results from this study will be presented and discussed at the conference.