6TROPICAL The Development of a Observing System Simulation Experiment (OSSE) Capability for the Operational Hurricane and Analysis Forecast System (HAFS)

Observing system simulation experiments (OSSEs) allow for robust statistical evaluation of the impacts, both positive and negative, of new observing platforms, techniques, or sampling strategies on numerical weather prediction (i.e., model forecasts). Specifically for tropical cyclone (TC) forecasting, OSSEs have been used over the last ~15 years to evaluate the impact of numerous data types on modeling TC structure, intensity, and track. In the summer of 2023, NOAA released the first version of the Hurricane and Analysis Forecast System (HAFS) for operational use in replacement of the Hurricane Weather Research and Forecasting (HWRF) model. Currently, the NOAA Quantitative Observing System Assessment Program (QOSAP) is developing an OSSE capability for HAFS to test and evaluate the potential impacts of observational platforms on hurricane track, structure, and intensity. To accomplish this, we use a high-resolution (1.4 km, 15-min) nature run, developed by ECMWF, to establish the initial and boundary conditions, simulated observations, and GFS output. This nature run (called HIPQ or ECO7999) produced a single TC that originated in the Gulf of Mexico at 00 UTC on 09 October 2019, reached peak intensity (low-end Category 2) by 15 UTC on 13 October, made landfall on the western coast of Florida by 12 UTC on 14 October, and finally dissipated by 18 UTC on 17 October (total duration: 8.5 days). In this study, we show preliminary results demonstrating the HAFS-OSSE capability and plans to use it for hurricane forecasting research. The novelty of this study is the ability to simulate and assess the impact of observing systems simulated at a higher resolution than previously accomplished using operational systems.