Forecasting Coastal Impacts from Tropical Cyclones along the US East and Gulf Coasts using the ADCIRC Prediction System

The proposed project will develop, deploy and critically evaluate a forecasting system that is capable of predicting wave, surge, sediment transport, and damage assessment, down to human scales, due to tropical cyclones impacting the US East and Gulf of Mexico coasts. The proposed forecasting system will leverage and greatly expand the capabilities of the existing ADCIRC Prediction System (APS) which is comprised of (i) the coupled ADCIRC+SWAN computational core; (ii) a national - regional system of unstructured computational meshes that contain information on bathymetry, topography, land cover and sub-grid scale features; (iii) interfaces to multiple meteorological models for forcing; (iv) the ADCIRC Surge Guidance System to manage / execute the forecast process, including execution of ensembles; (v) extensive experience performing event based forecasting for tropical cyclones impacting the US East and Gulf of Mexico coasts. APS forecasts (often several hundred for each storm including ensemble members) have been generated for every significant tropical cyclone that has threatened the US East and Gulf of Mexico coasts during the past decade. For the proposed project, the APS will be enhanced to include updated computational meshes including new bathymetry, topography and land cover data provided by team members engaged in task 1 of the proposed NOPP project; ingest of the Navys COAMPS-TC tropical cyclone meteorological model as forcing; evaluation of the newly available ADCIRC+WaveWatchIII computational core; inclusion of enhanced wave-surge physics; and assimilation of coastal water levels. APS output will be coupled to a suite of 1D and 2D XBeach simulations to evaluate morphology change and sediment transport at differing levels of detail as a storm approaches land. Water level and wave output directly from APS and from the APS+XBeach simulations will then be used for damage assessment from aggregated to local scales. Year 1 efforts will focus on modifications to the APS software, e.g., ingest of COAMPS-TC, initial ADCIRC+WWIII evaluation, wave-surge physics enhancements, mesh updates, setting up XBeach at a national scale and evaluating the system for hindcast events and/or reanalysis of forecast events. Model updates and evaluation will continue in Years 2-4 primarily outside of hurricane season, whereas during hurricane season we will produce daily forecasts of coastal impacts beginning five days prior to predicted landfall for at least three named storms per year.