DISCUSSION: It is well-known that the period between early May and late June tends to be the seasonal peak for severe weather outbreaks across the contiguous United States. Having said that, the typical seasonal peak for severe weather outbreaks across western/central Canada tends to be several weeks after that period of time. The reason for this time lag in the seasonal severe weather peak across parts of Canada is chiefly due to the change in the average position of the polar and sub-tropical jet streams across North America. During the Summer-time season, the polar jet stream consistently shifts much farther northward as the influences from the sub-tropical jet stream tend to overtake those presented by the polar jet stream.
It is this period of transition which favors severe weather across the south, central, and northern Plains regions of the United States. As the average position of the polar jet stream continues shifting northward, it is the clash between the polar jet stream and the northward shifting sub-tropical jet stream which facilitates an increasingly greater severe weather threat across parts of western/central Canada. On July 14th, 2000, this was precisely the case as a nasty tornado impacted areas both in and around Pine Lake, Alberta, Canada. Unfortunately, this was a particularly deadly and destructive tornadic event which left brutal memories on the minds of many people living across this part of Canada. To learn more about this particular tornado event, click on the following link.
©2017 Meteorologist Jordan Rabinowitz