An Aircraft Investigation of Mesoscale Convection over Lake Michigan during the 10 January 1984 Cold Air Outbreak

Abstract Surface, upper air, aircraft and satellite observations during the Lake-Effect Snow Studies (LESS) field program have been examined to study the properties of a cloud-topped boundary layer (CTBL) that formed in response to a northerly flow of continental polar air over Lake Michigan on 10 January 1984. An analysis of inversion base heights shows that the depth of the convectively mixed boundary layer ranged from 1.0 to 1.9 km across the central part of the lake from Wisconsin to Michigan, to an uncharacteristically high value of 2.4 km near the south end of the lake in Indiana. Spatial cross sections and streamline analyses show that the polar air was first modified by Lake Superior and then by the full fetch of Lake Michigan. Aircraft datasets of ambient air temperature, virtual potential temperature, specific humidity, liquid water content, and the u, v, and w wind components sampled at a rate of 20 s−1 by the NCAR King Air and Queen Air have been analyzed to determine the structure and interac...