RAPIDS (Rainstorm Analysis & Prediction Integrated Data-processing System)

RAPIDS (Rainstorm Analysis & Prediction Integrated Data-processing System) is a rainstorm forecasting system that incorporates the best features of SWIRLS and numerical weather prediction (NWP) model forecasts. The goal of RAPIDS is to blend or merge outputs from SWIRLS with those from NWP to generate an optimal QPF for operational guidance in rainstorm situations. It provides hourly updated QPF for the next 6 hours at horizontal resolution of 2 km. RAPIDS consists of 3 components: (a) SWIRLS QPF, (b) QPF from convective-permitting NWP model and (c) the blending algorithm. The NWP model is developed based on the Non-Hydrostatic Model (NHM) of the Japan Meteorological Agency. The HKO NHM system features two model domain with horizontal resolutions at 10 km and 2 km. The latter inner model, also called RAPIDS-NHM, is operated in hourly update cycle where radar Doppler velocity and reflectivity are assimilated to provide quantitative precipitation forecasts up to the next 15 hours.