HAFS Ensemble in AWS Cloud for 2023 Hurricane Real Time Forecasts

Lack of skillful high-resolution ensemble is a great challenge for the forecasters in NHC and JTWC to issue TC intensity, structure change, and hazards (wind, wave and storm surge) probability forecasts. To fulfil the gap, the Hurricane Analysis and Forecast System (HAFS) based ensemble prediction system (EPS) was ported to the Amazon Web Service cloud, which is running in real time to provide hurricane probabilistic forecast guidance for NHC forecasters in 2023 hurricane season. The stochastic physics in HAFS-EPS includes Stochastically Perturbed Physics Tendencies (SPPT), Stochastically Kinetic Energy Backscatter (SKEB) and Stochastically Perturbed PBL Humidity (SHUM). The initial and boundary conditions come from the NCEP operational GEFS 21-member forecast data. The performance of HAFS-EPS for 2023 Atlantic and east Pacific hurricane forecasts was compared with the global GEFS and ECMWF ensemble forecasts, which demonstrates the advantages of the higher resolution regional ensemble forecasts for hurricane track, intensity, Rapid Intensification (RI) probability, and hazards probability guidance.