A WC-130 instrumented aircraft will be deployed in the Western North Pacific region near Guam during 21 July-18 August 1992 to obtain in situ measurements in Mesoscale Convective Systems embedded in tropical cyclones. Four hypotheses related to different tropical cyclone track modification or genesis mechanisms will be tested. The scientific basis for these hypotheses is described and observations and models of midlatitude mesoscale convective systems are reviewed to provide a basis for planning the WC-130 missions. Aircraft operations and the Experiment Operations Center are described, along with tentative flight tracks. Descriptions of the real-time observations and the data to be archived for post-experiment analyses are provided.