Evaluating Hurricane Analysis and Forecast System (HAFS) Forecasts using Alternate Physics Configurations

The National Oceanic and Atmospheric Administration (NOAA) Unified Forecast System (UFS) Hurricane Analysis and Forecast System (HAFS) has been running operationally since 2023 with two distinct configurations. One major difference between the two HAFS configurations are the physics parameterizations as a way to increase model diversity. Therefore, exploring alternate physics configurations to maintain physics diversity remains a priority. Furthermore, as a relatively new operational modeling system, it is particularly important to understand the model performance for critical simulation aspects, such as precipitation and storm structure, through standardized verification and other diagnostics. This presentation will establish baseline performance of the operational HAFS forecasts using the enhanced Model Evaluation Tools (METplus). Several recent select storms will be highlighted, with an emphasis on landfalling storms, rapid intensification periods, and difficult to forecast cases. Sensitivity of alternate physics configurations will be explored for these storms, with performance compared to the operational baselines as well as observations. In addition to the impact on track, intensity, and wind radii verification; rapid intensification, quantitative precipitation forecast (QPF) verification, boundary layer structure and large-scale environmental diagnostics will be evaluated. In addition to the goal of increased physics diversity across HAFS configurations, this study will address potential physics unification across UFS applications.

Much of this work hinges on working closely with physics scheme developers to better understand how to optimally configure select parameterizations and to evaluate performance at the process level. One avenue for engagement in this area is through the Developmental Testbed Center (DTC) Visitor Program. Opportunities to partner with the DTC to work in areas aimed at improvement to the operational hurricane guidance, which has been a proven mechanism for research to operations (R2O) success, will be discussed.