9616728 Arritt The summertime Great Plains low-level jet is phenomenon known to be associated with severe weather events. Better understanding of the low-level jet could lead to better forecasts of severe weather within the Great Plains. The Principal Investigator will use a combination of numerical modeling and observational analysis to quantify the relative contributions of boundary-layer processes and synoptic dynamical forcing in the formation of the Great Plains low- level jet. The effect of divergence induced by the low-level jet on mesoscale rainfall systems also will be investigated. The project will use data from recently implemented observing systems and will adopt new strategies for isolating the contributions of the various processes that lead to the low-level jet. Emphasis will be given to the examination of physical processes that have been indicated in previous modeling studies as important for the low-level jet and its subsequent effects on mesoscale precipitation systems, but have not yet been confirmed by observations. Accomplishment of the research will provide improvements in our understanding of the fundamental issues in the dynamics of the low-level jet, and will support improvements in the prediction of nocturnal rainfall in the Great Plains region. ***
