Coupling the Rapid Refresh Forecast System (RRFS) to a National Water Model (NWM) configuration of WRF-Hydro and Evaluating Warm Season Convective Forecasts

Warm season convection across the Contiguous United States initiates at small spatial scales (<5 km) and weak large-scale dynamical forcing, and is sensitive to land-surface energy, moisture, and radiation (EMR) flux partitioning. While convective-allowing models such as the operational High Resolution Rapid Refresh (HRRR) have high-resolution treatment of topography, land use and land cover, they have simple treatment of land surface hydrologic processes that are often important to governing surface EMR flux partitioning and resulting precipitation. The next generation atmospheric model, the Rapid Refresh Forecast System (RRFS), intends to include more advanced Earth modeling; in particular more robust land-atmosphere interactions. Current research and development to couple the 3-km RRFS to a 1-km National Water Model configuration of the WRF-Hydro hydrological model is underway to provide a more thorough treatment of many of these surface hydrologic processes. We complete retrospective simulations of a 15-20 July 2019 case study for both the coupled RRFS-NWM model and an uncoupled RRFS control. Results suggest that the coupled model produces significant changes to land-surface EMR and temperature fields relative to the uncoupled RRFS control run. Results will be compared to available observational networks, including surface meteorological stations and DOE Atmospheric Radiation Measurement (ARM) data in the Southern Great Plains.