In the research described here, we have constructed at tightly coupled set of methods for monitoring, steering, and applying visual analysis to large scale simulations. This work shows how a collaborative, interdisciplinary process that teams application and computer scientists can result in a powerful integrated approach. The integrated design allows great flexibility in the development and use of analysis tools. This work also shows that visual analysis is a necessary component for full understanding of spatially complex, timedependent atmospheric processes. Overview For large scale atmospheric simulations one would like a tight coupling between the simulation, the observational database on which it is based, and the visualization/ analysis process by which it is understood. In fact there should be feedback, in the form of steering, between the latter and the simulation, since this will yield much more accurate representations of atmospheric processes and a significantly more focuse...