Development of a lake snow intensity index: A case study

Authors: Arthur Samel*, Bowling Green State University, Adam Burnett, Colgate University, Christopher Karmosky, SUNY Oneonta, Justin Hartnett, SUNY Oneonta
Topics: Climatology and Meteorology, Cryosphere, Water Resources and Hydrology
Keywords: snow, lake effect, intensity index, synoptic climatology
Session Type: Virtual Guided Poster
Day: 4/7/2021
Start / End Time: 3:05 PM / 4:20 PM
Room: Virtual 54
Presentation File: No File Uploaded

Intense “lake effect” snowfall occurs to the lee of the Great Lakes when cold air travels over the much warmer lakes. This study develops a Lake Snow Intensity (LSI) index based on circulation and thermodynamic “centers of action” that are identified with the occurrence of heavy lake effect snowfall at a single location in the Tug Hill Plateau of New York State, which is located downwind of Lake Ontario. Daily snowfall data for the period 1995-2019 are analyzed to identify 210 days when snowfall exceeded the NWS winter storm warning criterion of nine inches during a 24-hour period. North American Regional Reanalysis (NARR) 3-hourly data for circulation and thermodynamic variables are then used to identify the centers of action over a spatial domain that encompasses the Great Lakes region. A principal components analysis (PCA) with a varimax rotation of sea level pressure is first performed to determine the primary patterns that occur during heavy snow events. A composite analysis of the remaining NARR fields based on the largest/smallest scores for each PC is then used to isolate the centers of action. A HYSPLIT back trajectory analysis is also used to determine both fetch and residence time over Lake Ontario preceding each event and provide a measure of lake contributions to vapor flux and instability. Finally, a multiple regression analysis is performed to develop the LSI, which is based on the centers of action and back trajectories, where the LSI is proportional to daily snowfall amount.