Understanding the reasons for the location and timing of the onset of convective weather is a fundamental research question and important to the forecasting of weather. Convergence along mesoscale atmospheric boundaries and topographic effects are primary mechanisms for convective cloud initiation and development and in determining the distribution of precipitation. The availability of data from recent field research experiments and advances in numerical computer model capabilities provide an opportunity to advance knowledge of these processes. The Principal Investigator will use data collected from recent field programs to initialize and verify an advanced atmospheric numerical model. He will examine the contributions, interactions and sensitivities of the physical processes leading to convective storm development along atmospheric boundaries. He also will examine the influence of topography on the development and organization of clouds and precipitation.