Evaluation of the Rapid Refresh Forecast System during the 2023 NOAA Hazardous Weather Testbed Spring Forecasting Experiment

The 2023 NOAA Hazardous Weather Testbed Spring Forecasting Experiment (2023 SFE) was conducted by the NWS/Storm Prediction Center (SPC) and OAR/National Severe Storms Lab (NSSL) from 1 May – 2 June 2023. The goals of the 2023 SFE included exploring research-to-operations projects, conducting model evaluations, and testing real-time severe weather forecasting tools and techniques. In the 2022 SFE, subjective model evaluations showed that the deterministic and ensemble versions of the Rapid Refresh Forecast System (RRFS) performed similarly to the operational High-Resolution Rapid Refresh (HRRR) and High-Resolution Ensemble Forecast (HREF) systems in severe weather forecasting applications. Similar evaluations of the RRFS compared to the HRRR and HREF occurred during the 2023 SFE. The results presented here add a quantitative component to the subjective SFE model comparisons for severe weather forecasting applications. Hourly fraction skill scores (FSS) were calculated for each deterministic run and ensemble using forecast reflectivity greater than 40-dBZ during each convective day (i.e., 12 UTC-12 UTC) of the 2023 SFE. Muti-Radar/Multi-Sensor System (MRMS) reflectivity was used as the observational dataset. The objective verification of the RRFS provides additional evidence regarding the readiness of the RRFS to replace the operational baselines (i.e., HRRR and HREF) for severe weather forecasting. These evaluations are important for the NOAA/NWS model unification effort in assessing current and future forecast systems.