Rapid Refresh Forecast System Development for Version 2

The Unified Forecast System (UFS) Rapid Refresh Forecast System (RRFS) application will be NOAA’s flagship hourly updating, convection-allowing deterministic and ensemble prediction system and, with its implementation, will facilitate the retirement of several operational convection-allowing modeling (CAM) systems in the present production suite. This new 3-km system will extend over a large North American domain. Through support from the UFS-R2O project along with other collaborations across the UFS CAM application team, and particularly between GSL and EMC, the first version of the RRFS has been finalized. With the first version frozen, development attention has shifted to work on the second version of the RRFS. Two foundational changes are being tested including the transition to the Joint Effort for Data Assimilation Integration (JEDI) software framework and the MPAS (Model Prediction Across Scales) dynamic core. In addition to these changes, additional capabilities will include enhancements to the data assimilation design including use of additional observations, enhanced multiscale assimilation techniques and coupling of earth system components. Complementing data assimilation advancements will be model physics improvements for more scale-aware adaptivity including sub-grid cloud interactions. Forecast ensemble design changes are also being evaluated using the MPAS dynamic core and various sources of spread. This presentation will highlight many of these testing and development efforts for RRFSv2 including opportunities for collaboration across the UFS community.