Forecast: Chance of major winter storm?

Issued November 20, 2017: Covering the period from November 24 to November 30

This map shows the forecasted temperature anomalies for December across the United States and southern Canada produced by the CFS model. Looking at the map you can see that the warmest temperatures, compared to average, are forecasted to be just to our southeast. Most of agricultural Manitoba is forecasted to see temperatures that are 1 to 2 C above average, with southeastern parts of Manitoba expected to see December temperatures around 2.5 C above average.

It looks like we’ve settled into an early winter pattern that has seen a dominant area of high pressure over western North America and a trough of low pressure over eastern North America. Under this pattern we have seen the main storm track cutting across north-central Canada, placing much of southern and central Manitoba into a pattern of fairly dramatic swings in temperature. This pattern looks to continue right through to the end of the month.

This forecast period begins with an area of high pressure building in behind the area of low pressure that brought snow to central and northern regions earlier in the week. Temperatures will start off on the cool side as the high slides across our region on Wednesday, but will start to warm up once again as another area of low pressure begins to organize to our west. This low is forecasted to track across the northern prairies on Friday, placing all of southern and central regions in the warm sector. Expect daytime highs to soar into the low single digits. We’ll see some rain or freezing rain late in the day Friday as a cold front drops through the region.

There will be a slight cool down over the weekend as the western ridge of high pressure quickly rebounds, shunting the coldest air off to our northeast. Expect daytime highs to be in the -3 to -6 range, with overnight lows around -12 C. The weather models then show a weak low tracking across central regions on Monday that should help to boost daytime highs back above the zero-degree mark.

Attention then turns to a much stronger storm system that is forecasted to develop to our southwest by next Wednesday and then track northeastward into northwestern Ontario on Thursday. Confidence in this system is low, but the potential does exist for this to become a major winter storm.

Usual temperature range for this period: Highs -12 to 1 C, Lows -21 to -7 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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