A Climatology of Short-Wave Troughs in the Great Lakes Region and their Concurrence with Lake-Effect Snow

The Great Lakes region (GLR) often receives prolific amounts of lake-effect snowfall during each cold season (October–March). Upper-level features such as short-wave troughs can influence the location and intensity of this snowfall. A seven-year (2007–2014) cold-season climatology of 500-hPa short-wave troughs was developed for the Great Lakes region using RUC/RAP analyses. A total of 607 short-wave troughs were cataloged, an average of approximately 87 per cold season. Five types of short-wave troughs were identified based on their movement into the GLR. This short-wave trough climatology was compared to the lake-effect cloud band climatology created by Laird et al. (2017) to determine how frequently short-wave troughs occurred concurrently with lake-effect cloudiness. The results showed that 380 of the 607 short-wave troughs were concurrent with lake-effect clouds. Short-wave troughs rounding the base of a long wave were found to have the highest frequency of concurrence. Over 65% of these 380 short-wave troughs impacted at least four of the five Great Lakes. Lake Michigan was impacted most frequently, while Lake Erie was impacted the least, most likely due to the preferred path of the short-wave troughs across the Great Lakes region and the propensity for Lake Erie to become frozen in the middle of the cold season.