85th AMS Annual Meeting

Thursday, 13 January 2005: 1:45 PM
A high resolution nearshore wave model and bar forecast model for northwestern California
Troy Nicolini, NOAA/NWS, Eureka, CA; and G. B. Crawford, E. Rogers, T. Williams, E. M. Devaliere, and D. Saucedo
A high resolution nearshore wave model is applied for a portion of the coastal waters of northwest California, in support of National Weather Service coastal forecasting efforts in the region. The model will be used for general wave and swell forecasting in the coastal waters (0 to 60 nautical miles), and to develop a bar forecast model for the entrance of Humboldt Bay, California. The SWAN model is being used for this project. It is a third generation spectral wave model applicable to small scale, coastal regions with shallow water and ambient currents.

Wind forcing is obtained from National Weather Service 's Graphical Forecast Editor database. These are gridded fields on a 2.5 km scale for wind speed and direction that represent the best possible wind forecast developed by forecasters at the Weather Forecast Office in Eureka, California. Wave input at the outer boundaries of the model grid is obtained from the regional wave model, WAVEWATCH III. Tidal current at the harbor entrance is parameterized based on a tidal model developed for Humboldt Bay using ADCIRC, a two-dimensional, depth integrated finite element circulation model.

The SWAN model is run in real-time, with forecasts extending to three days. Wave model output will be used for two distinct purposes. First, wave parameters from the model will be used to populate National Weather Service gridded forecasts for the coastal waters region. These will include wind wave height and swell height, direction, and period. Output from the model will also be used to issue a point specific forecast for the hazardous entrance to Humboldt Bay. Initially, this will include height, period, and direction of waves at the bar entrance, with the breaking tendency of the waves to be added at a future date.

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