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<br />PREFACE <br />By their very nature, mesoscale phenomena require extensive obser- <br />vation networks which span three orders of magnitude of scales from 2 <br />to 2000 km. This study uses a new automated objective analysis and <br />display system to describe and understand the convective structure of <br />meso-8 convective systems observed in the Texas High Plains Cooperative <br />Program (HIPLEX) during 1979. The technique uses a band-pass filter <br />analysis of synoptic-scale and mesoscale wavelengths and combines these <br />to produce a meso-6 scale analysis focused on phenomena having 200 km <br />wavelengths. This hybrid analysis technique uses the derived mesoscale <br />vertical motion profiles to initialize model simulations of mesoscale <br />triggering effects on cloud development. The cloud model predictions <br />of potential for convective development provided an objective analysis <br />of the natural variability of convective clouds and precipitation. <br />Rawinsonde data collected from seven sites every 3 h for 20 cases were <br />used in the analysis to develop conceptual models of the mesoscale <br />triggering mechanisms believed to control convective cloud development <br />and precipitation. Digital radar echo observations and rain gage <br />data were used to describe the characteristics of different types of <br />precipitation events. <br /> <br />Four classes of summertime precipitation events were defined and <br />analyzed: 1) isolated convective cells, 2) cloud clusters, 3) cloud <br />lines and 4) mesosynoptic systems. <br /> <br />The dynamics of different types of cloud systems are largely <br />explained by a jet streak conceptual model. Upper-level convergence of <br />-5 to -40 x 10-5/s produces subsidence in jet quadrants 1 and 3, thereby <br /> <br />iii <br />