Last week’s forecast got the general weather pattern correct but again missed out on the details. The temperatures ended up warmer than forecasted, especially over Alberta. The push of cold air last weekend missed Alberta entirely pushing further east than expected. This resulted in colder temperatures for Manitoba. The models were correct on a return of mild Pacific air across the Prairies by the start of this forecast period. Unfortunately the weather models have shifted towards a colder medium range outlook.
We start this forecast period with an area of low-pressure sliding southeastwards through the southern Northwest Territories and into northern Manitoba. This low is pulling mild air northwards, which means a continuation of mild temperatures in Alberta, while Saskatchewan and Manitoba are seeing a rapid rebound from the cold start to the week.
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On Thursday, the weather models show an area of low pressure moving off the Pacific. This will push inland and help to develop a strong area of low pressure over northern Alberta. This low is forecast to quickly move southeast overnight Thursday and through the day Friday before exiting into northwestern Ontario. Precipitation from this low will fall over the northern half of Alberta, along with central Saskatchewan and Manitoba.
Once this low pushes through, the door will open for Arctic high pressure to drop southwards over the weekend. Once again, the coldest air looks to be over Saskatchewan and Manitoba, but Alberta won’t totally miss out. It looks, like the cold snap will be short lived, with milder Pacific air forecasted to move back in by the middle of next week.
Alberta
Another couple of days of above freezing temperatures are in store as energy moves in off the Pacific. This energy will help develop an area of low pressure over the northern half of the province on Thursday. The counterclockwise rotation around the low will continue to pump mild air northwards with daytime highs pushing near 10 C over far southern regions and around 3 to 5 C over central and northern regions. Snow will develop over the northern half of the province during the day Thursday and linger into Friday. Areas to the north of the lows track could see upwards of 10 to 15 cm of snow while other regions will likely only see 2 to 5 cm.
Once the low departs to the east on Friday, Arctic air will slide southwards. While the core of cold air will be over Saskatchewan and Manitoba, temperatures will drop significantly over Alberta. Expect daytime highs by Saturday or Sunday to be in the -20 C over central and northern regions and around -15 C over the south. Overnight lows are forecasted to be in the -24 to -27 C range. By Monday, the center of the Arctic high will have dropped into the northern U.S. which means the flow around the high will begin pulling milder Pacific air back into the region. Expect daytime highs to warm back into the -5 C range on Monday and then rise back to around or even above the freezing mark by Tuesday or Wednesday.
Saskatchewan and Manitoba
After a cold start to the week, mild Pacific air is making a rapid return. The mild air began moving into Saskatchewan on Tuesday and will make it presence felt in Manitoba by Wednesday. Expect daytime highs to be around the freezing mark on both Wednesday and Thursday with overnight lows only falling to around -5 C. The area of low pressure forecast to form over northern Alberta on Thursday will quickly drop southeastward overnight Thursday and into Friday morning. Central regions of Saskatchewan and the Interlake regions of Manitoba will see most of the snow from this system. Accumulation may reach 10 cm. Due to the quick motion of this system I don’t think the amount will be much higher.
As the low passes, Arctic high pressure will begin to drop southwards. The pressure gradient between these two systems will bring some strong northerly winds to Saskatchewan beginning Thursday night. These will arrive in Manitoba on Friday, making for some fairly unpleasant conditions.
The weekend looks to be cold as Arctic high-pressure slides to the south. Expect daytime highs only to be in the -20 to -24 C range with overnight lows falling to around -32 C or possibly a bit colder on Sunday and Monday morning. As the high slides to the south, mild air is forecasted to begin flooding across the Prairies on Tuesday with daytime highs by Wednesday expected to be in the -5 to -8 C range. The big question is whether the mild air will stick around or if we’ll see a repeat of Arctic air moving back in by the following weekend.
— Daniel Bezte is a teacher by profession with a B.A. (Hon.) in geography, specializing in climatology from the University of Winnipeg. He operates a computerized weather station near Birds Hill Park, Man. Contact him via email with your questions and comments.
