For much of the cold season each year, satellite and radar observations reveal the tell-tale signs of lake-effect snow storms: Areas of low-level clouds originating over each of the Great Lakes and snow spreading over the lake and land areas to the east. It is thought that particularly intense storms can occur when lake-effect clouds stretch from one lake to another, suggesting that increased moisture and decreased stability due to the upwind lake give the lake-effect storm a “head start” in development. Observations, however, indicate that this “head start” is often hampered or eliminated by processes over the intervening land and coastal regions.
This presentation will focus on a case during the Ontario Winter Lake-effect Systems (OWLeS) field experiment when lake-effect clouds and snow from Lake Erie crossed over Lake Ontario, potentially contributing to particularly intense snows to the east of the latter lake. Among the questions to be discussed are: How does the plume of modified air from Lake Erie change the lake-effect storm over Lake Ontario? How does the boundary layer structure and circulations change from land, coastal area, to open water over Lake Ontario? Finally, what can we learn about the coastal processes using the new UI/PRI Atmospheric scanning mobile LiDAR systems?