9422499 Wakimoto Physical forcing that occurs on small spatial and time scales (mesoscale) often determines the timing, location and severity of various weather phenomena. The Principal Investigator proposes to apply principals of mesoscale analysis to a variety of weather phenomena including tornadogenesis, study of convection in the boundary layer along what is termed horizontal convective roles, and to the study of oceanic cyclogenesis. The tornadogenesis study is focused on determining the physical factors that cause some severe thunderstorms to produce tornadoes while others do not. The Principal Investigator will participate in the second phase of the Verification of Origins of Tornadoes Experiment (VORTEX) as well as continue analysis of data collected during the first phase in the Spring of 1994. A unique aspect of this investigation is the first use of airborne Doppler data for the study of tornadogenesis. The study of horizontal convective roles is a continuation of analysis of data collected during the Convection and Precipitation/Electrification. This study is focused on one of the most common types of boundary layer convection and will include a study of how horizontal convective roles interact with the sea breeze. The third component will investigate the fine scale details of oceanic cyclogenesis using data from the Experiment on Rapidly Intensifying Cyclones over the Atlantic. Preliminary radar syntheses have revealed shallow mesoscale circulations that form along an intense warm front. This mesoscale feature appears to be the incipient circulation that can lead to rapid cyclogenesis when it comes into a proper phasing with an upper-level short wave trough. ***