Short-range rainfall forecast in Hong Kong

Studies have shown that many landslides in Hong Kong are rainfall-induced. While there is an on-going effort to stabilize the substandard slopes and to implement various preventive measures, it is necessary to have a system to forewarn the public of landslide risk at times of heavy rainfall to complement such work. The starting point for any Landslip Warning System and emergency response and preparedness plans is a reliable assessment and prediction of the rain development situation in real time. In this paper, some operational practices currently adopted at the Hong Kong Observatory on the prediction of heavy rainstorm events will be introduced. These include the main forecasting tools based on numerical weather prediction (NWP) systems and guidance derived from weather radar observations. The performance as well as the limitations of these tools will be discussed. The potential and the possibilities of further improvement towards more accurate and extended quantitative precipitation forecast (QPF) would be evaluated.