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Article
Synoptic-Scale Environments Conducive to Orographic Impacts on Cold-Season Surface Wind Regimes at Montreal, Quebec
Journal of Applied Meteorology and Climatology
  • Alissa Razy, Israel Meteorological Service
  • Shawn M. Milrad, McGill University
  • Eyad H, Atallah, McGill University
  • John R. Gyakum, McGill University
Submitting Campus
Daytona Beach
Department
Applied Aviation Sciences
Document Type
Article
Publication/Presentation Date
3-1-2012
Disciplines
Abstract/Description

Orographic wind channeling, defined as dynamically and thermally induced processes that force wind to blow along the axis of a valley, is a common occurrence along the St. Lawrence River Valley (SLRV) in Quebec, Canada, and produces substantial observed weather impacts at stations along the valley, including Montreal (CYUL). Cold-season observed north-northeast (n = 55) and south-southeast (n = 16) surface wind events at CYUL are identified from 1979 to 2002. The authors partition the north-northeast wind events into four groups using manual synoptic typing. Types A and D (“inland cyclone” and “northwestern cyclone”) are associated with strong lower-tropospheric geostrophic warm-air advection and near-surface pressure-driven channeling of cold air from the north-northeast, along the axis of the SLRV. Type C (“anticyclone”) shows no evidence of a surface cyclone and thus is the least associated with inclement weather at CYUL, whereas type B (“coastal cyclone”) is associated with predominantly forced wind channeling along the SLRV. Type D of the north-northeast wind events and all south-southeast wind events exhibit similar sea level pressure patterns. The respective magnitudes of the pressure gradients in the Lake Champlain Valley south of CYUL and the SLRV play a large role in determining the favored wind direction. Soundings of the various event types illustrate substantial differences in temperature structure, with a large near-surface temperature inversion particularly prevalent in north-northeast events. The results of this study may provide guidance in forecasting winds, temperatures, and observed weather in and around the SLRV, given certain synoptic-scale regimes.

DOI
https://doi.org/10.1175/JAMC-D-11-0142.1
Publisher
American Meteorological Society
Additional Information

Dr. Milrad was not affiliated with Embry-Riddle Aeronautical University at the time this article was published.

Citation Information
Alissa Razy, Shawn M. Milrad, Eyad H, Atallah and John R. Gyakum. "Synoptic-Scale Environments Conducive to Orographic Impacts on Cold-Season Surface Wind Regimes at Montreal, Quebec" Journal of Applied Meteorology and Climatology Vol. 51 Iss. 3 (2012) p. 598 - 616
Available at: http://works.bepress.com/shawn_m_milrad/21/