The National Hurricane Center Model Evaluation Process for the Operational Implementation of the Hurricane Analysis and Forecast System Version 1 (HAFSv1) Models

The National Hurricane Center (NHC) tropical cyclone guidance suite leverages a variety of dynamical and statistical models to create skillful consensus aids that support operational forecasts. Consensus aids developed and maintained by NHC range from relatively simple deterministic consensus aids formed by equally weighted model means to highly complex probabilistic consensus aids developed using a blend of model and observational predictors. The operational implementation of the Hurricane Analysis and Forecast System Version 1 (HAFSv1) models for the 2023 season presented a critical juncture for consensus aids in the NHC guidance suite. Comprehensive evaluations were required to assess the implications of the two HAFSv1 models supplanting their predecessor models—the Hurricane Weather Research and Forecasting (HWRF) model and the Hurricanes in a Multi-scale Ocean-coupled Non-hydrostatic (HMON) model—given that the HWRF and HMON predecessors ranked among the most skillful dynamical models providing intensity guidance to forecasters at NHC.

The model evaluation process at NHC will be discussed through the lens of the HAFSv1 operational implementation. This talk will primarily focus on evaluating the impacts of the HAFSv1 models supplanting HWRF and HMON in the NHC simple track, intensity, and wind radii consensus aids and in the Hurricane Forecast Improvement Program (HFIP) Corrected Consensus Approach (HCCA). The configurable NHC Forecast Verification Software provides the basis for conducting in-house model evaluations. Homogeneous verification measures, such as errors, biases, and skill will be discussed for the HAFSv1 evaluation, along with externally generated verification measures such as contingency tables and associated skill scores for predicting rapid intensification (RI). Ongoing efforts to integrate the HAFSv1 storm-relative nests into the NHC operational version of the Advanced Weather Interactive Processing System (AWIPS) will be shown via the AWIPS environment in the cloud. Furthermore, capabilities to generate post-processed probabilistic guidance within the cloud AWIPS environment as a surrogate to potential operational workflows will be demonstrated with a subset of the HAFS Ensemble in Real-time on the Cloud (HERC) from the Environmental Modeling Center.