The dynamic and thermodynamic effects of the Tibetan Plateau on atmospheric general circulation has been recognized for some time. Additionally, the Plateau has a pronounced influence on the local weather. One of the most interesting meteorological phenomenon produced over the Plateau is a mesoscale atmospheric disturbance known as the southwest vortex. During the warm season, vortices of this type are among the most important rain- producing systems in China and are often responsible for severe flood events. These weather systems appear to bear some resemblance to the mesoscale convective systems that occur in the United States and other locales, but it is not clear if they are the same phenomenon. The Principal Investigators will use previously collected special data sets in diagnostic and numerical modeling studies of southwest vortices. Specifically, they will attempt to determine what meteorological factors are important to the formation and intensification of southwest vortices and how these systems relate to mesoscale convective systems.//