Lake to Lake Cloud Bands Originating over Lake Huron: Spatial Patterns and Variability

Lake-effect snowfall over and near one of the Great Lakes can be locally enhanced by the influences of lake-effect convective bands originating over upwind lakes, particularly in the eastern Great Lakes region. Many processes associated with “lake-to-lake” (L2L) bands are not well-documented. A previous study of L2L cloud bands originating over each of the Great Lakes found that they occurred frequently in conditions favorable for lake-effect snow, but did not address spatial variability of L2L bands from each lake. In preparation for the Ontario Winter Lake-effect Systems (OWLeS) field project, a study of dominant L2L bands originating from Lake Huron/Georgian Bay (LH/GB) was conducted to gain better insight into where bands are most likely to cross Lakes Erie and Ontario as well as the variations in band location for given environmental conditions. On 122 days during the 2004-12 winters, 138 dominant bands were identified. Bands were identified using visible satellite images near the time of peak climatological lake-effect intensity, 15 UTC, on each day. L2L bands were classified as dominant if they were either wider, longer, and/or had brighter tops than other lake effect clouds around them. This presentation will discuss synoptic patterns, atmospheric conditions, and lake conditions that were found to be favorable for the formation of L2L bands originating over LH/GB and spatial variations of their positions as they cross Lakes Erie and Ontario.