Temperatures have been dropping some and a patchy thin snow cover has been increasing across Western Canada during the past week, but so far November temperatures are still averaging several degrees warmer than normal. Winter weather is likely to be elusive for Western Canada during the next week or so, but there continue to be signs that a period of cold and snow might visit the Prairies later in the third week of November.
The accompanying chart of October temperatures provided by Agriculture and Agri-Food Canada shows widespread mild weather for the Prairies. By the time November wraps up we expect to see a similar temperature pattern even with the potential cold snap we expect for a few days in about 10 days.
Much of Canada remains on the mild side of normal due to the effects of the strong El Nino and the influx of Pacific air from west to east across the nation. This is a pattern quite typical of an El Nino, but there can be interruptions in the pattern occasionally.
Many of our computer models have been keying in to a turn to very low temperatures across Alaska during next week and the models continue to imply that arctic air will indeed develop from Alaska into the Yukon by this time a week from now. For a brief period, most guidance is showing a burst of this cold sliding southeastward into Western Canada as enough of a ridge develops across the Gulf of Alaska during the Nov. 20 to 23 period.
Does this mean a major pattern shift and the arrival of wintry cold and snow? Most likely not, since most all models bring back the flow of modifying Pacific air quite quickly later this month. The return of milder weather following the brief cold punch is why we feel November's temperature departure chart will look quite similar to October's.
The December outlook continues to strongly imply milder-than-normal weather across nearly all of Canada, but we can never rule out one or two brief surges of very cold weather. The reason being that the atmosphere usually undergoes brief breakdowns during an otherwise mostly stable pattern during most years and while the average of a month may be mild, a couple of brief periods of cold and snow can still take place.
Doug Webster can be reached at firstname.lastname@example.org
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