Initiation of convection over the Black Forest mountains on 12 August 2007 during COPS

Doppler-On-Wheels radar observations made on 12 August 2007 during the Convective and Orographically-induced Precipitation Study showed that precipitating clouds only developed in a confined region of the northern Black Forest. High-resolution simulations by the Weather Research Forecasting model accurately represented the location of the precipitation. The model was therefore able to provide an insight into the physical mechanisms responsible for the initiation and development of the convection. Heating on elevated surfaces generated warm, moist convective cores. Thermally-driven mesoscale flows created convergence lines that constrained the initial location of the convection within the cores. The interaction of cold-pool outflows, from the first clouds, with the existing thermal flows initiated secondary convection and heavier precipitation.