Evaluating HWRF Modeling of Landfallling Tropical Cyclones over Florida

This Study will analyze the triple-nest grid capabilities of the Hurricane Weather Research and Forecasting model (HWRF v3.4a) to investigate the impacts of rapid intensification (RI) over landfalling two tropical storms, Fay (August 2008) and the Florida Gale in October 2011. Both storms made landfall and brought significant rainfall within a short period of time over Florida which highlights the social and economic implications they impose. The focus of this research will be to: 1) expand our understanding of the effects high resolution models and forecasts can have on tropical cyclone operations, and 2) to improve the depiction of the structure and intensity of these two landfalling TC.

This study will emphasize on these two key changes in the conventional HWRF configurations and their effect on the intensity forecasts for both TS Fay and the Florida Gale. The main scientific questions to be addressed are as followed: 1) how well does the 27-9-3 km triple-nested grid capture the structure and intensity of the two systems before and after the RI event? 2) Does the microphysics scheme affect the land-ocean-atmosphere coupling with rapid landfall intensification? 3) What is the significance of forcing data used for the HWRF simulations?

Previous studies have shown that aerosols can have an effect on the cloud microphysics of tropical cyclones (TCs) and thus play an integral part with the rainfall distribution, we will first modify the cloud microphysics parameters in HWRF and monitor any significant changes to the forecast in term of structure and intensity for both storms. This study will also utilize the ECMWF ERA-interim to compare it with GFS used by HWRF to evaluate the significance of changing the initial forcing mechanisms for both cases. The ultimate goal is to improve the quality of the 48-72 hour forecasts relative to the feature locations and the overall magnitude of severity of landfalling tropical storms.