Lake-Effect Snowbands in Baroclinic Environments

Abstract

Lake-effect snowstorms are often observed to manifest as dominant bands, commonly produce heavy localized snowfall, and may extend large distances inland, resulting in hazards and high societal impact. Some studies of dominant bands have documented concomitant environmental baroclinity (i.e., baroclinity occurring at a scale larger than the width of the parent lake), but the interaction of this baroclinity with the inland structure of dominant bands has been largely unexplored. In this study, the thermodynamic environment and thermodynamic and kinematic structure of simulated dominant bands are examined using WRF reanalyses at 3-km horizontal resolution and an innovative technique for selecting the most representative member from the WRF ensemble. Three reanalysis periods are selected from the Ontario Winter Lake-effect Systems (OWLeS) field campaign, encompassing 185 simulation hours, including 155 h in which dominant bands are identified. Environmental baroclinity is commonly observed during dominant-band periods and occurs in both the north–south and east–west directions. Sources of this baroclinity are identified and discussed. In addition, case studies are conducted for simulation hours featuring weak and strong along-band environmental baroclinity, resulting in weak and strong inland extent, respectively. These contrasting cases offer insight into one mechanism by which along-band environmental baroclinity can influence the inland structure and intensity of dominant bands: in the case with strong environmental baroclinity, inland portions of this band formed under weak instability and therefore exhibit slow overturning, enabling advection far inland under strong winds, whereas the nearshore portion forms under strong instability, and the enhanced overturning eventually leads to the demise of the inland portion of the band.

The Seasonal Snowfall Contributions of Different Snowstorm Types in Central New York State

“…Since there are instances where lake-enhanced snow bands occur during cyclonic storms (Eichenlaub and Hodler, 1979;Liu and Moore, 2004;Owens et al, 2017;Kulie et al, 2021), storms were also categorized as lake snowstorms and nonlake snowstorms (Table 1). Lake snowstorms attempt to account for lake-enhanced snowfall events and are categorized similar to lake-effect snowstorms; however, precipitation and cloud structure does not have to be independent from other mesoscale storms and there does not have to be a six-hour gap in…”

“…However, distinguishing lake-effect snow from synoptically driven snow is complicated by mesoscale lake snow bands within large-scale cyclonic storms (e.g., Houze and Hobbs, 1982;Kristovich et al, 2000;Tardy, 2000;Owens et al, 2017;Kulie et al, 2021). This can result in additional snowfall, which is termed lake-enhanced snow (Eichenlaub and Hodler, 1979;Liu and Moore, 2004).…”