ABSTRACT

Observational and numerical modeling studies have greatly improved the understanding of "classic" lake-effect snowstorms and led to improvements in forecasting them. In particular, research focused on the mechanisms leading to lake-effect convective boundary layer growth and mesoscale circulations, and how they differ from oceanic marine boundary layers, has helped stimulate these improvements. In addition, results and tools from these earlier research studies have allowed for initial investigations of complex processes associated with "non-classic" lake-effect storms, where lake effect systems are modified by synoptic or sub-synoptic phenomena or upwind air masses are modified by neighboring lakes. As a result of prior NSF supported research, the Principal Investigators reported on investigations of several non-classic lake-effect systems including (1) enhanced snowfall caused by seeding of lake-effect clouds by higher level cloud layers, (2) convective cloud bands that develop over a lake and extend across an intervening land mass to a second downwind lake, and (3) synoptic frontal modifications resulting from the interaction with a large mid-latitude lake.

This research project seeks to build on past research results and address unanswered scientific questions using new observations and numerical models to broaden understanding of non-classic lake-effect systems and environments. Specific research objectives are to: (1) use unique observations from the Great Lakes Ice Cover-Atmospheric Flux (GLICAF) project to understand and quantify the relationship of surface fluxes to heterogeneous pack ice concentrations, (2) use case-study, climatic, and numerical model simulations to understand the structure of multiple-lake bands and the influence of environmental parameters on their development and evolution, (3) quantify the influence of environmental conditions on cold frontal structure and evolution as synoptic fronts interact with lake-effect systems, (4) use Doppler radar measurements, accompanied by atmospheric and environmental datasets to determine the favorable conditions and the organization of mesoscale snow events associated with lake-effect systems over small mid-latitude lakes, and (5) examine cloud and ice spectrum characteristics, as well as radiative flux profiles, across a range of lake-effect systems.

Results of this research will give valuable insight into complex processes that often complicate winter forecasting of mesoscale phenomena common to the Great Lakes region. These results will be communicated to the meteorological community through journal and conference articles and to the operational community through regional workshops and presentations at National Weather Service offices.

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