Investigations of the Mesoscale and Microscale Structure of Midwest Winter Cyclonic Storms

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Due to the potential for disruption of human and economic activities, the precipitation characteristics of winter-time cyclones are of great practical as well as scientific interest. It has been know for some time that the heaviest precipitation from these systems occurs in relatively narrow precipitation bands. Over the past several years, the organization of precipitation bands in cyclonic storms has received a great deal of attention with a variety of physical mechanisms being proposed to explain the characteristics of these bands. Interestingly, most of these observational studies of bandedness in winter cyclonic storms have been conducted in coastal regions which experience quite different meteorological conditions than the mid-continental area. The principal Investigators propose a pilot observational and numerical modelling study in Illinois to begin to define the characteristics of mid-continent cyclonic precipitation bands. The observational component of this research will involve enhanced serial sounding of the atmosphere and two advanced instruments for meteorological research -- wind profiler and Doppler radar. A major focus is to relate the organization and structure of precipitation bands to flow fields and thermodynamic structure of larger scale phenomena such as fronts, lower and upper level jet streams, and zones of deformation flow.