The Global-Nested Hurricane Analysis and Forecast System (HAFS): Results from the 2019 Atlantic Hurricane Season

The Hurricane Analysis and Forecast System (HAFS) is developed for the next-generation high-resolution tropical cyclone modelling system. HAFS-global enables a static 3-km nest inside a 13-km global FV3GFS. This configuration allows for testing the impact of 2-way interactions between the global and the high-resolution nested domains. HAFS re-calibrates global GFS planetary boundary layer physics and surface physics parameterizations so that it is adaptive to the high-speed wind regime in TC conditions. The adjustments of these parameterizations are based on in-situ observations from NOAA’s flight field program and other observed data.

During the 2019 hurricane season, real-time forecasts of HAFS-global will be performed from August 1 through October 31 under the Hurricane Forecast Improvement Program’s demo project. HAFSV0.B will forecast 4 times daily out to 168h. The experiment will provide an opportunity to evaluate the model’s capabilities in predicting TC track, intensity, and storm structure. Aggregate statistics and comparison with current TC models will be presented. Thorough case studies will also highlight some of the forecast challenges of the 2019 Atlantic hurricane season, and provide further insight into both the strengths and weaknesses of HAFSV0.B for further improvement and guidance for HAFS development and transition.