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Forecast: Expect a shift in weather pattern

Covering the period from December 9 to December 16

This map shows the total amount of precipitation that fell across the Prairies this fall (September to November) as a percent- age of the long-term average. It has been a very dry fall across Manitoba and eastern Saskatchewan. The region stretching from Calgary northward to Edmonton was also dry. The only “wet” areas were across southeastern Alberta stretching into northeastern Saskatchewan and up toward Saskatoon.

It wasn’t surprising that the weather models did such a good job predicting last week’s early-winter heat wave. The models had been consistently showing this happening for a while and they are usually correct when it comes to large weather features like this. For this forecast period, it looks like the weather pattern is going to shift toward a more seasonable one, which means colder weather and maybe, just maybe, some snow.

The start of this forecast period looks like it will be the last of the really warm days, as an area of arctic high pressure begins to build southward. This high is forecast to track through northern Manitoba and into northwestern Ontario by the weekend. Expect sunny to partly cloudy skies along with cooling temperatures. Daytime highs by the weekend should be in the -10 to -12 C range, with overnight lows falling to around -18 C.

The weather models then show a couple of chances for snow between Sunday and Tuesday (Dec. 13-15) as pieces of energy break off from a Pacific storm system and race along the border. Currently, it looks like we will only see a dusting to maybe a couple of centimetres of snow from these systems. Temperatures will moderate ahead of these systems, with daytime highs climbing back up to around -5 C and overnight lows down around -14 C.

Looking a little further ahead, the weather models hint at a more active weather pattern developing as cold air is forecast to push southward across western North America. This pattern often spawns strong areas of low pressure over the southwestern U.S. and these often track northeastward. There is not a lot of confidence in looking this far into the future, but at least this may provide a little hope for those wishing for more snow.

Usual temperature range for this period: Highs, -17 to -3 C; lows, -26 to -12 C.

About the author

Co-operator contributor

Daniel Bezte

Daniel Bezte is a teacher by profession with a BA (Hon.) in geography, specializing in climatology, from the U of W. He operates a computerized weather station near Birds Hill Park.



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