A Real-Time Forecasting System for Hurricane Induced Storm Surge and Coastal Flooding

Hurricanes cause property damages and loss of lives in the U.S. every year. In 2004, four major hurricanes caused more than 5 billion dollars in damage each in Florida alone. Katrina in 2005 caused more than $200 billion dollars in damage. Major damage caused by a hurricane is usually associated with storm surge and coastal flooding. This paper presents CH3D-SSMS, a robust storm surge and coastal flooding forecasting system for tropical and extratropical storms. The basic forecasting system couples a storm surge and coastal flooding model (CH3D) with a shallow water wave model (SWAN) in a high resolution (50–500m) coastal/estuary/inland model grid. The coupled surge-wave model receives open boundary conditions of surge and wave from a global surge model (ADCIRC) and a global wave model (WAVEWATCH-III) which cover the Gulf of Mexico and Western Atlantic. Currently high resolution grids have been set up for the East Florida Coast (including St. Johns River, Indian River Lagoon, and adjacent coastal water), Tampa Bay and Charlotte Harbor, Florida Panhandle, and Chesapeake Bay and adjacent coastal waters. The forecast wind and atmospheric pressure information are provided by a number of NOAA wind models including NAM (North Atlantic Mesoscale), GFDL-Hurricane model, and an analytic model which uses GFDL hurricane parameters. Based on the forecast wind, the CH3D-SSMS produces an 84-hour forecast of water level, wave height/period/direction, flow field, and maximum of maximum (MOM) water level and inundation, every 6 hours. Prior to forecasting, the model performs a 24-hour nowcast using analysis wind. Performance of the CH3D-SSMS forecasting system has been demonstrated using results from 2003 (Isabel) and 2004 (Frances and Ivan) hurricanes. Forecasting of the impact of Hurricane Wilma on the Charlotte Harbor region is illustrated to reflect the current capabilities and weaknesses of the CH3D-SSMS as well as hurricane wind model. To improve the forecasting system, more accurate and efficient hurricane wind models and coupling of models of various processes and scales are needed. Hurricane-ground interaction should be incorporated into the hurricane wind model to produce more realistic near ground wind after hurricane landfall. Cyberinfrastructure should also be employed to facilitate regional and community collaboration.