ABSTRACT: A numerical model system is constructed to predict surface conditions over the open oceans for a typhoon case. Its atmospheric and oceanic components are the Weather Research and Forecasting (WRF) model and the NOAA WaveWatch version 3 (NWW3) model, respectively. The initial condition of the WRF is obtained from the NCEP aviation forecast, while the WRF-predicted surface winds serve as the boundary conditions for sea wave prediction of the NWW3.The capability of this model system is evaluated in terms of the predictions of surface wind and sea waves associated with the typhoon Bilis (No. 0604). This typhoon formed over the west side of Guam (141?E, 12?N) on July, 9, 2006, and moved northwestward across Taiwan to decay over southeast China on July, 15, 2006. Its moving track is reasonably predicted by the WRF with an averaged error of 99 km in 24-hr forecast and of 233 km in 48-hr forecast. These errors are in comparable ranges with the official typhoon forecasts conducted by weather services in the countries around the Pacific. The circulation pattern and intensity of surface winds and height of sea waves can be adequately portrayed by this prediction system in advance by 48 hrs. The dangerous and navigable semicircles of the typhoon are also clearly delineated. As such, the spatial domains of high wind and high sea are identified, providing potentially useful information for navigation safety.

KEYWORDS: Safety of Navigation, Weather Navigation, Typhoon, Weather Research and Forecasting (WRF), Meteorological Aspects, Weather Forecast, Sea Wave, Numerical Model System

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