A nonhydrostatic model has been developed for operational use from early 2004 to improve very short-range forecasts, especially the quantitative precipitation forecasts at the Japan Meteorological Agency (JMA). The governing equations are for the fully-compressible atmosphere and a time-split technique is employed for stable and economical integration of the acoustic and gravity wave terms. Cloud microphysics is implemented using a three-ice scheme, along with a moist convective adjustment scheme, which is adopted to suppress unrealistically strong updrafts. For further strengthening the computational stability, an advection adjustment scheme is incorporated in the model which controls computational errors of advection schemes. A 4D-Var analysis technique developed for the JMA mesoscale hydrostatic model is used to provide initial fields. From preliminary experiments, it is found that the model is successfully run with a time step of 30 seconds at 10km horizontal resolution, and has favorable features for heavy rainfall prediction in the 18-hour integration compared with the operational hydrostatic 10km model.