Application of WRF weather model to forecast precipitation in Nilwala river basin

The Weather Research and Forecasting (WRF) model is a numerical weather prediction and atmospheric simulation system designed for both research and operational applications. It was fine tuned to forecast precipitation over Nilwala river basin in Sri Lanka by investigating the impacts of its physics options on precipitation forecasting. In model fine tuning, impacts of microphyics schemes, cumulus schemes, land surface schemes, boundary layer schemes and long/shortwave schemes were investigated. Model predictions were compared with observed point rainfall data for three rainfall events to find reasonably good physics combinations. It was seen that the model combination, Ferrier microphysics scheme, Kain-Fritsch cumulus scheme, Rapid Update Curve land surface scheme, Yonsei boundary layer scheme, Rapid Radiative Transfer model longwave radiation scheme and Dudhia shortwave scheme yields good precipitation predictions over the basin when compared with the other physics combinations tested.