Evaluating HWRF Modeling of landfallling Tropical Cyclones over Florida

This Study will utilize the Hurricane Weather Research and Forecasting model (HWRF) with 27 and 9 km grid resolution to investigate the impacts of rapid intensification over landfalling Tropical Cyclones Fay (from 18 to 24 August 2008) and the Columbus Day storm in October 9, 2011. Both storms made landfall and brought significant rainfall over Florida. The focus of this proposed research are 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.

It is important to evaluate the capability of HWRF in terms of how well the precipitation and wind speeds of each respective Tropical Cyclones (TC) and consider their social and economic implications for the area. The objectives of this proposed research are to: 1) evaluate the accuracy of the wind field and rain band structures of both tropical cyclones (i.e., radii of 34, 50, 64 knot wind fields) before and after rapid landfall intensification, and to 2) evaluate how the cloud microphysics scheme affect forecasts of intensity change in terms of rainfall distribution. 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 the two storms.

The main scientific questions that will be addressed are as followed: 1) how well does the 27 and 9 km nested grid capture the structure and intensity of the two systems during landfall? 2) Can changes in the microphysics scheme improve the land-ocean-atmosphere coupling with rapid landfall intensification?

We will also examine the updated version of HWRF (v3.4a) which includes a 27-9-3 km triple nested grid capability. We will complete a qualitative analysis and compare the results of both versions to determine the model performance of landfalling TC over Florida.