Development of UFS-based Future Subseasonal to Seasonal Applications at NWS/NCEP

The next generation NWS/NCEP operational GFS and GEFS systems, GFSv17 (for medium-range deterministic predictions) and GEFSv13 (for subseasonal ensemble predictions), as well as the future seasonal forecasting system, SFSv1, are being developed as fully coupled atmosphere/land/ocean/sea-ice/wave/aerosols UFS applications. The final coupled system will consist of the FV3 dynamical core and CCPP atmospheric physics package, Noah MP land model, MOM6 ocean model, CICE6 sea ice model, WAVEWATCH III wave model, and GOCART aerosol model.

To date, eight coupled UFS prototypes (P1-P8) with increasing complexity, number of components, and component refinement have been constructed towards that target. Once a system prototype is finalized, it is tested to ensure that the configuration is stable. Deterministic forecast skill and biases are evaluated, and deficiencies needing developers' attention in subsequent iterations are identified for the aforementioned operational targets. Some notable achievements of this new global coupled system demonstrated by these prototypes will be discussed along with significant challenges which must be addressed by future prototypes/configurations.