Wednesday, 12 January 2005
Hurricane Isabel: A numerical model study of storm surge along the east coast of the United States
A two-dimensional, barotropic tide/surge forecast system, PCTides, developed by the U.S. Naval Research Laboratory, was used to study the prediction of storm surge associated with the approach and landfall of hurricane Isabel on the east coast of the United States in September 2003. PCTides was driven by three different forecast wind/surface pressure fields: the Navy Operational Global Atmospheric Prediction System (NOGAPS), the Navy’s Coupled Oceanic and Atmospheric Mesoscale Prediction System (COAMPS) and by a forecast developed using the Holland hurricane prediction model and a pathway predicted by the National Hurricane Center (NHC) before landfall. The Holland model was also run in a hindcast mode using the observed path of Hurricane Isabel. Results of the modeled storm surge were compared to National Oceanic and Atmospheric Administration (NOAA) water level observations at key locations along the hurricane’s path. Using winds and pressures defined from the observed path, PCTides was able to provide a very reasonable tide/surge prediction along the coast. Of the forecast cases, the surge generated by the COAMPS forcing was more accurate than that generated by the NOGAPS forcing, but both atmospheric models forecast a storm track west of the observed track. The path generated from the National Hurricane Center’s prediction, prior to landfall, had an eastward bias. Results from this case were not as accurate as the COAMPS driven model results.