Michigan region from an examination of the climatological record of 47 stations surrounding the lake. A
clear feature of the evaluation was a marked decrease in the frequency of November snow for much of the
basin during recent decades, which has not been matched by similar decreases in December, January, and
February. This implies a reduction of early season lake-effect snowfall; however, precipitation data can
be sensitive to observing practices and lake-effect snowfall is not easily distinguished from concurrent or
antecedent synoptic-scale precipitation. Therefore, the topic warrants case-level exploration, with a focus of
individual snow events.
One key aspect of the work is the ongoing generation of a WRF-based climatology of all November Lake
Michigan snow cases since 1950. These simulations utilize NCEP/NCAR Reanalysis data for initial and
boundary conditions, using the WRF Single-Moment 3-class microphysical scheme, the Eta surface layer
similarity scheme, the Mellor-Yamada-Janjic planetary boundary layer scheme, and the Kain-Fritsch
cumulus parameterization scheme. These simulations well-represent precipitation and other key features
of synoptic systems, while capturing the bulk features of lake-effect snow bands and some aspects of event
morphology. Additionally, the spatial distribution of simulated snowfall is largely consistent with the
observed snowfall distribution. Therefore, the results from this WRF-based climatology are compared with
a previous synoptic-based classification of the snow days in order to better understand the relative roles of
synoptic versus lake-effect snowfall.
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