We’re in a slack pressure pattern with no strong features controlling the weather, which you’d think would make for an easy forecast. That is not the case. Sure, it’s easy in the sense that not much is going on. But the devil is in the details, and with this type of pattern the details are hard to figure out.
This forecast period starts with high pressure slowly sliding to the east of the Prairies, an area of low pressure over northern Saskatchewan and another area of low-pressure moving northeastward into North Dakota. There’s also some weak ridging over Alberta and western Saskatchewan.
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The low over northern Saskatchewan and its accompanied warm front near the Saskatchewan-Manitoba border will be the focus of showers and thunderstorms as it slowly tracks eastwards. The North Dakota low may trap some of the moisture moving northwards , which would keep the heaviest rainfall to our south but provide plenty of clouds.
As the weekend approaches, weak upper-level ridging will be in place across the central and eastern Prairies while over Alberta a weak upper low will be tracking southeastwards out of the Yukon. This upper low will set the stage for showers and thunderstorms on Friday and Saturday before it moves into Saskatchewan and Manitoba by Sunday or Monday.
The slack or weak pattern looks to continue into much of next week, which makes it difficult to pinpoint which areas could see showers or thunderstorms, and on which days. Best chances for precipitation look to be over the eastern Prairies. This type of pattern also makes it difficult to predict where forest fire smoke will be.
Alberta
Weak upper-level ridging will bring sunny to partly cloudy skies on Wednesday and Thursday with northern regions seeing a good chance of smoke. Temperatures will be in the mid to upper twenties with overnight lows falling into the mid-teens.
On Friday, a weak upper low or disturbance is forecasted to begin dropping southeastwards out of the Yukon. This feature will destabilize the atmosphere, which should result in a good chance of showers, thundershowers, and a few thunderstorms. With all the clouds and precipitation, expect cooler temperatures. Daytime highs are forecasted to be around 20 C with overnight lows falling to around 12 C. This system should move off east by Sunday.
The weather models are showing weak upper-level ridging rebuilding over Alberta early next week. This should bring sunny to partly cloudy skies along with seasonable temperatures. Expect daytime highs to be in the mid-twenties with overnight lows in the 10 to 14 C range. Southern regions could see the odd afternoon shower or thundershower on Monday as a weak system skirts by to the south, but confidence in this feature is low.
Saskatchewan and Manitoba
As stated earlier, this region will be the focus for showers and thunderstorms to start this forecast period as an area of low pressure over northern Saskatchewan slowly slides to the east. This low will push a warm front through eastern Saskatchewan and into southwestern Manitoba during the day on Wednesday and through eastern regions of Manitoba by Wednesday night and into Thursday. The front will be the focus for showers and thunderstorms as it pushes through.
Timing of the front will determine the amount of rainfall. If the front moves through later in the day, there’ll be the best chance of seeing heavier rain amounts. Currently the weather models are showing total amounts from storms in the 10 to 15 mm range, but the slow motion of some storms could result in locally higher amounts. Even with the clouds and possible precipitation, daytime highs will continue to be in the mid to upper twenties.
Behind the front, weak upper-level ridging will begin to re-establish itself, which will bring sunny to partly cloudy skies over much of Saskatchewan and Manitoba on Friday and Saturday. A disturbance moving out of Alberta will bring increasing clouds and the good chance of scattered showers or thundershowers to Saskatchewan late Saturday and into Sunday morning. This feature should move into Manitoba on Sunday.
Skies should clear on Monday as weak high pressure works in, but another weak disturbance is forecasted to track by to our south on Tuesday and Wednesday. This should bring a return to partly cloudy skies along with the chance of widely scattered showers or thundershowers. Temperatures look to remain seasonable during this period with daytime highs in the mid-twenties and overnight lows in the low teens.
— 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.Â
