RAP/HRRR Model Physics Development

Abstract

The Rapid Refresh (RAP) and High-Resolution Rapid Refresh (HRRR) are real-time operational hourly updating forecast systems, which provide guidance for convective, aviation, renewable energy, and general weather applications at 13- and 3-km grid spacing, respectively. Both systems use the Advanced Research version of the Weather Research and Forecasting (WRF-ARW) model, which allows many WRF-community users to utilize either certain components or the full HRRR-physics suite for any application needed by operational, academic, and private sectors. Many different components of the RAP/HRRR, such as the turbulence (PBL + shallow-cumulus + deep convection), land-surface model, microphysics parameterizations, and numerical methods are under continued development. Special effort is made to incorporate scale-aware aspects into the turbulence parameterizations to improve weather forecasts not only for operational-scales, but also for higher resolution typically used in the academic and private sectors. This presentation will highlight the development of certain model components, showing the improvements over previous versions for precipitation, temperature, moisture, wind, and downward shortwave radiation with respect to a variety of observation types. Further, it will be shown that the efforts to generalize the turbulence parameterizations for any model configuration has directly benefited the performance of each system at their current operational configuration. Examples of case studies and retrospective periods will be presented to illustrate the improvements. Ongoing and future RAP/HRRR physics development will be touched upon.