Synoptic Climatology of Lake-Effect Snowfall Events in Indiana: What's the Best Recipe?

In order to better understand the sensitivity of Indiana lake-effect snowfall to the largescale environment, the climatology of Indiana events and a comparison group of “near-miss” cases with snowfall in adjacent southwest Michigan have been examined. Since lake-effect snowfall often occurs within the same reporting period as snow from migrating synoptic-scale systems, snowfall reports, surface and upper air analyses were used to isolate ostensibly pure lake-effect events for inclusion. With a minimum snowfall threshold of five cm, there are ~250 cases in the data set.

Peak event snowfall among long-term reporting stations is most sensitive to event duration and wind direction, with weaker sensitivity to thermodynamic, wind speed and shear parameters gleaned from the upstream sounding at Green Bay, Wisconsin. Composite largescale patterns within Reanalysis data include an upper-level trough and associated equatorial shift in the 300 hPa wind maximum within the Great Lakes region, with upper-level ridging near North Atlantic and North Pacific teleconnection centers of action. Ongoing and future work include a comparison of largescale patterns and sounding characteristics of these events and “near-miss” cases. Additionally, Weather Research and Forecasting (WRF) model simulations will be utilized in order to better understand the snowfall climatology, event sensitivity to the largescale environment, spatial snowfall distribution, and event morphology.