Evaluation of Hurricane Analysis and Forecast System Using Alternative Physics Configurations

The National Oceanic and Atmospheric Administration (NOAA) Unified Forecast System (UFS) based Hurricane Application, Hurricane Analysis and Forecast System (HAFS), was implemented into operations in June 2023 in advance of the North Atlantic (NATL) and Eastern Pacific (EP) basin hurricane seasons. For the initial operational capability of HAFS (HAFSv1.0), two distinct configurations were selected to eventually replace the regional operational hurricane forecast systems, Hurricane Weather Research and Forecast (HWRF) and Hurricanes in a Multi-scale Ocean-coupled Non-hydrostatic Model (HMON). One major difference between the two HAFS configurations are the physics parameterizations. Therefore, exploring alternate physics configurations to maintain physics diversity remains a priority. This presentation will explore the sensitivity of using Rapid Refresh Forecast System (RRFS) based physics within the HAFS for several select storms during the 2021-2023 hurricane seasons. Landfalling storms, rapid intensification periods, and difficult forecast cases will be highlighted (e.g. Ida 2021, Ian 2022, Lee 2023, Philippe 2023). In addition to the impact on track, intensity, and wind radii verification, rapid intensification, quantitative precipitation forecasts (QPF), and boundary layer structure will be evaluated. Performance will be compared to operational benchmarks as well as observations. The model QPF will be verified against Integrated Multi-satellitE Retrievals for GPM (IMERG) over water, and the Climatology-Calibrated Precipitation Analysis (CCPA) over land. In addition to standard QPF verification, evaluations using advanced methods such as track shifting, storm centric and object oriented verification will be shown using the enhanced Model Evaluation Tools (METplus). In addition to the goal of increasing physics diversity across HAFS configurations, this study will address potential physics unification across UFS applications.