Hurricane Analysis and Forecast System (HAFS) Stand-Alone Regional model (SAR) 2019 Atlantic hurricane season real-time forecasts

Hurricane Analysis and Forecast System (HAFS), a next generation convective-scale hurricane forecast system, is being developed to accelerate improvements in tropical cyclone (TC) intensity and track forecast skill within a unified global and regional modeling framework of the Unified Forecast System (UFS). It utilizes the finite volume cubed sphere (FV3) based global-regional modeling system for TC prediction. The system can be applied in either a high resolution regional stand-alone regional mode (HAFS-SAR) or a global model with a high resolution nest mode (HAFS-global). HAFS-SAR has been developed recently to cover the north Atlantic region for hurricane forecasts and includes new planetary boundary layer (PBL) and surface flux parameterization schemes designed specifically for TC predictions. The stand-alone regional model has a uniform 3 km horizontal resolution and 64 levels extending to 0.1 hPa vertically.

The HAFS-SAR experiments were conducted from August 1 to October 31 in real-time for the 2019 Atlantic hurricane season. This presentation will demonstrate the capability of the HAFS on convective-scale hurricane forecasts and systematic evaluation of its performance. The HAFS-SAR ran forecasts four cycles per day for a total forecast length of 126 hours. Results and statistics of these real time forecasts are analyzed and compared with other regional and global hurricane forecast systems in terms of track, intensity, storm size and structures.