CASPII and the Canadian cyclones during the 1989–92 cold seasons

The climatological characteristics of cyclogenesis and the associated storm tracks in the domain of 40–70°N and 50–140° W are studied for the four cold seasons of 1989–1992. It is found that surface cyclones affecting the Canadian territories originate mostly from the eastern slopes of the Rocky Mountains, the Atlantic coast of the United States (U.S.) and the eastern North Pacific basin. The explosive deepening of these systems is shown to occur preferentially along the Atlantic coast of both Canada and the U.S. It is also found that regions of most frequent occurrence of cyclones include Baffin Island, the Davis Strait, the northern Great Lakes and northern Newfoundland. A more detailed examination of the Canadian Atlantic Storms Program II (CASP II) season of January-March 1992 shows an anomalously large number of rapid cyclogenesis events occurring in the Atlantic coastal region of Canada. This anomaly is found in association with a persistent large-scale region of an unusually cold air mass.