The Rapid Refresh Forecast System: Looking Beyond the First Operational Version

The Global Systems Laboratory (GSL) in NOAA seeks to improve numerical prediction (NWP) across all weather hazards including severe convective weather, intense rainfall, winter storms, landfalling tropical systems and other small-scale phenomena such as smoke from wildfires. This model development is continuing within the Unified Forecast System (UFS), including the upcoming operational transition of the first version of the Rapid Refresh Forecast System (RRFS) in collaboration with NOAA’s Environmental Modeling Center (EMC). The RRFS 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, significant development progress has been made with the RRFS towards the first planned operational implementation in 2024 including a freezing of the first configuration during 2023. With the first version code freeze approaching later this year, many additional RRFS capabilities are being planned for implementation after the first version and this presentation will provide an overview of RRFS version two and beyond. These additional capabilities will include enhancements to the data assimilation design including a transition to Joint Effort for Data Assimilation Integration (JEDI), enhanced multi-scale assimilation techniques and coupling of earth system components. Complementing data assimilation advancements will be model physics improvements for more scale-aware adaptivity, sub-grid cloud interactions and other component updates such as improved dynamics.