Differences in Overlying Synoptic Environments between Lake-Effect and Non-Lake-Effect Snow Associated Colorado Cyclones

LES events generate up to 50% of annual snowfall for regions in the Great Lakes basin and generate abundant hazards including power outages and blizzard conditions. Synoptic environments associated with LES events are typically characterized by a mid-latitude cyclone (hereafter referred to as ‘cyclone’) passing over the Great Lakes region which generates surface wind fields conducive to maximum fetch. However, not all cyclones produce LES, and there is sparse, but increasing research devoted to assessing the differences in synoptic conditions between non-LES and LES environments. This study furthers this body of knowledge by analyzing the overlying synoptic conditions of LES and non-LES associated Colorado cyclones. A Colorado cyclone repository is developed by conducting a manual analysis over 17 meteorological winters using Weather Prediction Center (WPC) surface archive maps and the National Centers for Environmental Prediction (NCEP) National Center for Atmospheric Research (NCAR) Reanalysis dataset. This repository is then cross referenced with an existing LES repository developed by National Oceanic and Atmospheric Administration (NOAA) over the same time range to differentiate LES and non-LES producing Colorado cyclones. Furthermore, a climatology of LES and non-LES producing Colorado cyclones is developed by constructing synoptic composites using NCEP/NCAR Reanalysis data. These composites represent the average overlying synoptic conditions of Colorado cyclones during LES and non-LES situations.