AN IMPROVED NWP MODEL FOR FORECASTING THE PATHS OF TROPICAL CYCLONES

Abstract

An improved numerical prediction model for forecasting the paths of hurricanes and typhoons is presented. A constant circular vortex representing the tropical cyclone is translated each time step so that it is always centered at the cyclone's initial center point which is advected with the barotropic steering flow. The vortex flow advects the absolute vorticity of the steering flow thereby affecting the forecast speed and direction of movement of the vortex center. The vortex equations, the modified barotropic equation, and forecasts assuming both the 500-mb. flow and a vertically weighted mean flow as the steering flow are shown.