Most of the Canadian Prairies has been teased by a little bit of snow and lower temperatures during the past week with Manitoba and northern Saskatchewan being the main recipients. There are signs that a stronger winter weather event may evolve across the region by Sunday and Monday as a strong system slides over the top of the strong ridge across the Gulf of Alaska and southward through Western Canada.
As the days pass, it seems that more ingredients may come together to bring a pretty widespread light to moderate snow and a couple of days of temperatures more in keeping with December. Upslope conditions should develop across Alberta and Saskatchewan Sunday into Monday, as an Arctic-source high pressure system moves cold air southward from northwest Canada. Upslope winds and cold advection become a recipe for snow during the winter and can bring a major temperature drop within a short period of time.
Is this a long-term weather pattern change or just a blip in an otherwise quiet pattern? It appears that the latter may be true, with a rather strong warm-up with dry weather for the second half of next week. Model forecasts for the first part of November do not look overly wintry, but a couple of short bursts of colder weather and snow are being advertised in between mild, dry conditions.
Climate model outlooks for the entire month of November continue to favor temperatures a little milder than normal, but that does not mean that a couple of cold shots with some snow can't still occur. Precipitation forecasts for November show wetter-than-normal conditions, so keep the snow shovel handy.
As the days grow shorter and temperatures drop, talk of what the upcoming winter will bring is always brought up this time of year. There are many clues that meteorologists and climatologists look at, some old and some new. Each year there are new studies that try to bring to light a better method to determine the winter outlook. Some are more interesting and seem to have more credibility that others, but the job of forecasting the winter a season in advance is still more like throwing dice.
Early signals for winter, defined as December through February, point toward a changeable temperature pattern. The Pacific Ocean ENSO state is forecast to be neutral, and as of now the threat for strong blocking across northeastern Canada or Greenland as we saw last spring appears to be minimal. This leaves us with the idea that the winter may feature periods of mild, dry weather intertwined with periods of very cold, snowy weather.
Pacific air and Arctic air may play tag with the Prairies; temperatures could average out not too far from normal. However, temperatures may not be at near normal levels very much of the time as weather systems transition across Canada and the northern U.S.
Doug Webster can be reached at email@example.com
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