A major component of the Hurricane Forecast Improvement Program (HFIP) response to Section 104 of the Weather Research Forecasting Innovation Act of 2017 (Wx Act) was to progress and operationalize an advanced numerical prediction based hurricane model.

On June 27, 2023 the Hurricane Analysis and Forecasting System (HAFS) entered operational status on the National Oceanic and Atmospheric Administration (NOAA), National Weather Service (NWS), National Centers for Environmental Prediction (NCEP) Weather and Climate Operational Supercomputing System 2 (WCOSS2). The HAFS model is NOAA’s next generation hurricane forecast model which builds on the world class multiple moving nest skills developed by HFIP utilizing the Hurricane Weather Research and Forecasting (HWRF) model.

The NOAA core HFIP partnership and its ability to leverage community collaborations for HAFS decreased duplication of effort and streamlined the development processes allowing HAFS to go from concept to operations in approximately 5 years. NOAA’s NWS and NOAA’s Oceanic and Atmospheric Research (OAR) including NWS Environmental Modeling Center (EMC), OAR Atlantic Oceanographic & Meteorological Laboratory (AOML) Hurricane Modeling and Prediction Program and NOAA's Cooperative Institute for Marine & Atmospheric Studies (CIMAS) jointly developed HAFS.

Additionally, HFIP’s strong community of hurricane researchers, atmospheric and physics modeling experts, and the University Corporation for Atmospheric Research (UCAR) Development Testbed Center (DTC) were heavily involved in technical skill development, code management, and testing.

These collaborations led to HAFS being the first ground-up regional coupled model to go into operations under the Unified Forecast System (UFS); due in part to utilization of atmospheric simulation capabilities from the Global Fluid Dynamics Laboratory (GFDL) Finite-Volume Cubed-Sphere Dynamical Core (FV3), the same core used in the U.S. Global Forecast System (GFS).

More information on HFIP plans and the continuing development of HAFS can be found in the HFIP Strategic Plan

The Hurricane Forecast Improvement Program (HFIP) real-time experiments serve as the back-bone of R2O transition for hurricane models and products in NOAA. The purpose of these experiments is to demonstrate that the application of advanced science, technology, and increased computing will lead to the desired increase in accuracy, and other improvements in forecast performance as laid out in the HFIP strategic plan. While operational models have to work within the allowed operational computing resource limitations, HFIP real-time experiments assume that resources will be found to greatly increase available computer power in operations above that planned for the next two to five years. These experiments allow for advances in model dynamics, physics, innovative techniques in data assimilation and product generation within the framework of operation and next-generation NOAA hurricane models that cannot be tested on current operational computers because of size and time requirements, but can instead be tested on NOAA R&D machines such as the Jet and Orion systems. Model configurations and approaches must be at least at RL4 or higher to be selected for obtaining HFIP computational resources on the R&D machines following a call for proposal in early April. The HFIP real-time experiments start on August 1 and end on October 31 each hurricane season. 

Progress of these real-time runs are evaluated after each season to identify techniques that appear particularly promising to operational forecasters and/or modelers. These potential advances can then be blended into operational implementation plans through subsequent model upgrades, or further developed outside of operations with subsequent testing. While products from these experimental models are not used to generate forecast warnings, they are shared with the hurricane community and are available to the NHC forecasters for providing additional guidance as well as for obtaining critical inputs for further improving NOAA models and products. Additionally, these experiments have provided for a continuous and active collaboration between NCEP/EMC, AOML/HRD, NCEP/NHC, ESRL/GSL, NCAR and DTC which culminates in successful testing and evaluation, and subsequent implementation of significant improvements to the operational Hurricane models at NOAA/NWS/NCEP.

For almost a decade, HFIP real-time experiments have been conducted using versions of operational models (HWRF, HMON). Beginning with the 2019 hurricane season, experimental versions of the UFS-based HAFS system were introduced to the suite. The experimental products from the 2024 HREx runs may be available on the HFIP web-site. Led jointly by developers at NWS/NCEP and OAR/AOML, these efforts would efficiently and effectively transition the latest advances to operations for Hurricane models next year and serve as prime examples of successful community-driven R2O efforts for the broader UFS community. UFS-based HAFS advancement and initial operational implementation targets would benefit immensely from a continuation of these HAFS-based HFIP experiments and expedient usage of NOAA’s R&D HPC resources in a broad community-based development effort.