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[1] A Gulf of Mexico performance evaluation and comparison of coastal circulation and wave models was executed through harmonic analyses of tidal simulations, hindcasts of Hurricane Ike (2008) and Rita (2005), and a benchmarking study. Three unstructured coastal circulation models (ADCIRC, FVCOM, and SELFE) validated with similar skill on a new common Gulf scale mesh (ULLR) with identical frictional parameterization and forcing for the tidal validation and hurricane hindcasts. Coupled circulation and wave models, SWANþADCIRC and WWMIIþSELFE, along with FVCOM loosely coupled with SWAN, also validated with similar skill. NOAA's official operational forecast storm surge model (SLOSH) was implemented on local and Gulf scale meshes with the same wind stress and pressure forcing used by the unstructured models for hindcasts of Ike and Rita. SLOSH's local meshes failed to capture regional processes such as Ike's forerunner and the results from the Gulf scale mesh further suggest shortcomings may be due to a combination of poor mesh resolution, missing internal physics such as tides and nonlinear advection, and SLOSH's internal frictional parameterization. In addition, these models were benchmarked to assess and compare execution speed and scalability for a prototypical operational simulation. It was apparent that a higher number of computational cores are needed for the unstructured models to meet similar operational implementation requirements to SLOSH, and that some of them could benefit from improved parallelization and faster execution speed.

The National Oceanic and Atmospheric Administration (NOAA), specifically the National Weather Service’s (NWS) National Hurricane Center (NHC), utilizes the hydrodynamic Sea, Lake, and Overland Surges from Hurricanes (SLOSH) model to simulate storm surge in 27 basins along the U.S East and Gulf Coasts. This information is provided to federal, state, and local partners to assist in a range of planning processes, risk assessment studies, and decision making. Based on climatology, tens of thousands of hypothetical hurricanes are simulated in each basin, and the potential storm surges are calculated. Storm surge composites—maximum envelopes of water (MEOWs) and maximum of maximums (MOMs)—are created to assess and visualize storm surge risk under varying conditions. While MEOWs and MOMs provide a local assessment of storm surge risk, they do not provide a national perspective owing to the 27 discrete grids. National assessments must therefore merge the grids together, which is a laborious task requiring considerable SLOSH and hydrodynamic modeling expertise. This paper describes the technique used to create national inundation maps for category 1–5 hurricanes using the SLOSH MOM product, and it provides a simple quantitative assessment of the potential societal impacts. Approximately 22 million people along the U.S East and Gulf Coasts are vulnerable to storm surge. For all hurricane categories, a substantial portion of the coastal population and housing units are at risk, and many evacuation routes become inundated. Florida is the most vulnerable state with 40% of its population at risk. These maps and analyses provide a new way to view, analyze, and communicate national storm surge risk and inundation.

b y B e t t y H . M o r r o w , J e f f r e y K . L a z o , Ja m i e R h o m e , a n d J e s s e F e y e n Survey findings from forecasters, emergency managers, broadcast meteorologists, and the public pave the way tow ard more effective communication o f storm surge forecasts associated w ith tropical and extratropical cyclones. AMERICAN METEOROLOGICAL SOCIETY JANUARY 2 0 15 BARS' | 35