Overview of Regional Modeling Development at NOAA/ESRL/GSD

The Global Systems Division (GSD) at NOAA’s Earth System Research Laboratory 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. GSD’s mission is making forecasts better with stakeholder interests across a diverse portfolio including aviation, severe, renewable energy, hydrological and air-quality sectors. Model development on the regional scale has emphasized frequent data assimilation cycles with hourly-updating forecasts in the 13-km Rapid Refresh (RAP) and 3-km High-Resolution Rapid Refresh (HRRR) systems. The NWP systems developed at GSD are based on community modeling, data-assimilation, and post-processing software. GSD has contributed to the development of the Smirnova land-surface model, MYNN PBL parameterization, and Grell-Freitas-Olson (GFO) convective parameterization in WRF. This development is continuing with FV3, NOAA’s new global and regional NWP model as part of the Unified Forecast System (UFS). A goal is to provide a flexible physics package that performs well across model grid spacings from O(10 km) to O (100 m), including in complex terrain. The future of convective-allowing NWP systems like the HRRR will be ensemble analyses and forecasts, to increase skill and provide uncertainty information for forecast applications. A prototype HRRR Ensemble (HRRRE) is under development and is running experimentally in real time. Ensemble diversity comes from initial-condition perturbations, boundary-condition perturbations, and stochastic physics. Experiences with HRRRE will guide development toward an operational implementation of a stand-alone regional FV3 single-core convective-allowing ensemble analysis and forecasting system, formally known as the Rapid Refresh Forecast System (RRFS). This presentation will provide an overview GSD’s regional model development activities related to (1) data assimilation and physics for the existing RAP/HRRR model systems including both deterministic and ensemble forecast capabilities, (2) post-processing and agile verification software that help inform the model development process and (3) stand-alone regional FV3 model and Joint Effort for Data assimilation Integration (JEDI) software to support NOAA’s next-generation model and data assimilation systems.