HRRR Model Development For Complex Terrain Applications In Support of The Wind Forecast Improvement Project 2

Abstract

The Wind Forecast Improvement Project II (WFIP 2) is a multiagency effort to improve forecasts of low-­level wind within the Columbia River Basin. The High­Resolution Rapid Refresh (HRRR) is singled­-out as an operational system targeted for improvement. Many different components, such as the turbulence parameterizations (PBL + shallow­cumulus), land-surface physics, and numerical methods are under development. All components are meant to become publicly available in future releases of the Advanced Reseach version of the Weather Research and Forecasting (WRF­-ARW) model. Special effort is made to incorporate scale­-aware aspects into the turbulence parameterizations to improve wind forecasts not only for operational­-scales, but also for higher resolution typically used in the private sector. An experimental nest within a development version of the HRRR, with grid spacing of 750­ m, is centered over the Columbia River Basin to support the scale­-aware development efforts. This presentation will overview the various components of the model development, the methodology of model testing (case studies, short-­term retrospective periods, and long­term re-forecasts), and introduce important enhancements to the model validation and data analysis tools developed specifically for HRRR development within WFIP 2. 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.