Numerical simulations conducted with the NCAR Weather Research and Forecasting (WRF) Model extend the observational analysis and provide an objective dynamical evaluation of storm initiation, development mechanisms, dynamics and microphysics. A capping inversion in the lee of the Andes is important in preventing premature triggering. The South American Low Level Jet impinging on low mountains to the east of the main Andes ranges triggers extremely deep and intense convection. Mesoscale organization into leading line/trailing stratiform system occurs as the storms propagate eastward. The simulated mesoscale systems closely resemble the storm structures seen by the TRMM satellite as well as the overall shape and character of the storms shown in the GOES satellite data. A sensitivity study removing small-scale topographic features that are hypothesized to focus deep convective initiation determines the role of the topography in triggering and geographical focusing the extreme convection. Results of the numerical experiment in which smaller mountain features are removed will be presented at the conference. In addition, insights into the mesoscale processes that keep the South American MCSs tied to the topography following upscale organization and development longer than those in the U.S. will be highlighted and shown.