Atmospheric circulation structures associated with freezing rain in Quebec City, Quebec

Abstract

Introduction: An analysis of freezing rain (FZRA) events in Quebec City (YQB), Quebec, Canada, a climatologically active area, is counted over a 30 year period (1979-2008) in an attempt to better understand the synoptic patterns, severity, and frequency of such events. Methods: of the 218 individual events, 48 are classified as severe and are given a more in depth analysis at various pressure levels. events are partitioned into five categories based on synoptic patterns, including the location and organization of surface features, 500 hpa trough location and length, and instantaneous geostrophic wind direction at YQB at the first hour of reported FZRA. Composite analyses of atmospheric variables are then created for each category, and the latter are then compared. Results: each of the five categories has a unique thermodynamic and dynamic signature. Identifying these signatures within forecast models may significantly improve the prediction of freezing rain events. discussion: fzrA events have not been studied extensively in the SLRV and so identifying these aforementioned signatures within forecast models may significantly improve the prediction of freezing rain events.