Analysis of high resolution observational data gathered during a mesoscale field experiment in central Alberta (LIMEX-85) has led to a conceptual model of severe convective outbreaks in Alberta. It is proposed that most severe convective events result when upper-level cooling, associated with an advancing, synoptic-scale trough, occurs in phase with strong surface heating over the Alberta foothills. The deep destabilization over the elevated topography acts to amplify the mountain-plain circulation and to generate mesoscale upslope moisture transport. Concurrently, the surface synoptic pressure gradient gives rise to east-northeasterly winds which advect the moisture-rich air of the eastern plains into the lower-branch of the mountain-plain circulation. In this manner, the plains moisture is permitted to reach the convectively active foothills through underrunning of the capping lid. The end product of the synoptic-mesoscale interactions is the initiation of well-organized, severe convective storms which move eastward with the westerly component of the mid-tropospheric winds. A statistical analysis based on archived hail data provides additional evidence for the key synoptic-scale features of the conceptual model.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.74676 |
| Date | January 1991 |
| Creators | Smith, Stephan Bryan |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Meteorology.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001239489, proquestno: AAINN67842, Theses scanned by UMI/ProQuest. |
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