Parcel Trajectories Leading to Lake Erie Lake-Effect Events

Lake-effect environments can include various types of convection, with wind-parallel bands (WPBs) being the most common and shore-parallel bands (SPBs) typically being the most impactful from large snowfall totals. While the typical wind direction over individual lakes resulting in these convection types are generally understood, there is limited knowledge of the originating air masses and long-distance parcel trajectories that lead to lake-effect convection in the Great Lakes region. This project aims to uncover the primary air parcel pathways for SPBs and WPBs associated with lake-effect environments on Lake Erie. Lake-effect days and type of convection for Lake Erie during the ten winters (DJF) of 2009/10 - 2018/19 were determined from a long-term database derived from GOES visible daytime satellite imagery. The NOAA HYSPLIT model was employed to calculate an ensemble of air parcel back-trajectories that started over Lake Erie on each lake-effect day and covered the preceding five days (120 hours). North America and its surrounding oceans were divided into 11 regions to determine the main origins of air parcels for each convection type. The Northwest region was a prominent starting point for both types, but the American West region had substantial air parcel origins for SPBs, while the Hudson Bay region played a larger role for WPBs. There was considerable variation for both convection types throughout the decade, suggesting that the sources of these air parcels can differ on both a yearly scale and a monthly scale.