The effects of precipitation on a model of cumulus cloud initiation and development over mountains are studied by numerically integrating the equations of motion, equations of conservation of water substance, and the thermodynamic energy equation. The model is two-space dimensional with a vertical wind shear in a stable, incompressible atmosphere. Heating and evaporation at the valley and mountain interact with the initial ambient flow to initiate clouds which produce shadows on the surface and cut down both heating and evaporation. The model is restricted vertically to 3.5 km and horizontally to 7.0 km. Several precipitation parameters are studied in this model. One, the critical water content determines when cloud water converts to rainwater. A second, the autoconversion rate, determines how rapidly the cloud water converts to rainwater. The third parameter determines how quickly the precipitation evaporates beneath the cloud. The rainwater first forms by autoconversion and is then increased by... Abstract The effects of precipitation on a model of cumulus cloud initiation and development over mountains are studied by numerically integrating the equations of motion, equations of conservation of water substance, and the thermodynamic energy equation. The model is two-space dimensional with a vertical wind shear in a stable, incompressible atmosphere. Heating and evaporation at the valley and mountain interact with the initial ambient flow to initiate clouds which produce shadows on the surface and cut down both heating and evaporation. The model is restricted vertically to 3.5 km and horizontally to 7.0 km. Several precipitation parameters are studied in this model. One, the critical water content determines when cloud water converts to rainwater. A second, the autoconversion rate, determines how rapidly the cloud water converts to rainwater. The third parameter determines how quickly the precipitation evaporates beneath the cloud. The rainwater first forms by autoconversion and is then increased by...