Evaluating the Impact of Global Ensemble Perturbations for Partial Cycling EnKF Members on RRFS Prototype Performance

The Rapid Refresh Forecasting System (RRFS) will be the future operational convective-allowing regional NWP system for North America. Included in this system is an ensemble component, the RRFS Ensemble, which serves both as an operational forecasting tool as well as the source of ensemble statistics for the cycling system’s data assimilation component.

We evaluated the performance of two such RRFS Ensemble prototypes, using the Agile Benchmark Testing Framework our team has incorporated into the Unified Forecast System (UFS) Short-Range Weather Application (SRW App). The evaluated ensemble forecasts differed in the source of ensemble perturbations: one ensemble was periodically re-centered using a 30-hour forecast from the Global Ensemble Forecast System (GEFS), and the other using the 6-hour forecast from the Global Data Assimilation System (GDAS). We will present objective ensemble and probabilistic verification statistics comparing these two prototypes to each other, as well as a comparison to existing ensemble products such as the High-Resolution Ensemble Forecast (HREF).