Storm Morphology and the Influence of Orography on Lake-Effect Precipitation

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Lake-effect precipitation is both a significant weather hazard and an economic driver for locations like the US Great Lakes. Forecasts of lake-effect snow have improved over the past few decades, but there are still outstanding questions about specific processes that can have a major impact on the distribution of snowfall during a lake-effect event. One factor that will be addressed by this research award is the role of topography in determining the impact of lake-effect precipitation. The prevailing understanding of how topography affects lake-effect precipitation is that the lift provided by nearby hills or mountains results in an invigoration of the convection and therefore the precipitation. However, recent research has discovered that this is not always the case, and that there is a decrease in storm depth and convective vigor in certain topographic areas. This project will address the issue of topography and lake-effect precipitation through analysis of observations from two distinct areas: the Tug Hill plateau downstream of Lake Ontario in New York, which was heavily instrumented during the 2013-14 Ontario Winter Lake-effect Systems (OWLeS) campaign, and Honshu Island in Japan which receives copious amounts of lake-effect snow due to the long fetch over the Sea of Japan. Analysis and modeling efforts will be conducted to take advantage of the stark contrasts in geographic, topographic, and lake-effect storm characteristics to broaden the understanding of orographic influences on lake-effect precipitation. The impact of this award should be improved weather and climate forecasts in lake-effect regions as well as enhanced collaboration with international scientists working on similar issues. The results of the award would be disseminated through multiple means including a frequently visited blog site and through K-12 outreach. Multiple graduate students would be involved in the research, ensuring training of the next generation of scientists. This award will improve understanding of how orography affects lake-effect snowfall through observational analysis and numerical modeling of lake-effect storms on the Tug Hill Plateau of New York and Honshu Island in Japan. These two regions have prolific amounts of lake or ocean-effect snowfall, but there has been little comparison of the mechanisms that produce the precipitation enhancement. The overall goal of the project is to advance knowledge and prediction of the influence of hills, mountains, and upland regions on lake-effect precipitation. Three main scientific questions would be addressed: 1) How does the presence of topography affect the initiation, distribution, and intensity of lake-effect precipitation? 2) What are the key mechanisms controlling the orographic ratio (lowland vs upland) during lake-effect storms? 3) How does the orographic ratio vary with environmental conditions, cloud processes, lake shape and size, and terrain scale and geometry?