Weather radars provide several types of information useful for defining the state and evolution of a rain system: the rainfall rate, the vertically integrated rainwater content, and the advection velocity. The very short-term rainfall forecasting models dedicated to the survey of catchments (particularly those subject to flash-floods) are typically designed to include one or more of these information types. A general formulation of these models associating an advective term and a dynamical term is proposed by Lee and Georgakakos (1991). The model proposed in this work extends the simplified dynamical formulation developed by Seo and Smith (1992) and French and Krajewski (1994) by explicitly accounting for orographic enhancement and by combining the dynamical component with an advection-diffusion scheme (Smolarkiewicz 1983). This paper presents an initial evaluation of the model for two rain events in the mountainous Cevennes region located in the South of France. One-hour and two-hour lead-time forecasts for four catchments are performed and compared with two simple methods: persistence and advection.