The cold front is coming! The cold front is coming! After a pleasant weekend, things will turn sharply cooler this week as a potent cold front plows through southern Manitoba today.
22°C / 7°C
Mainly cloudy with chance of showers
Today will see a strong cold front sweep through southern Manitoba. The front will move through western Manitoba early in the morning, exiting the province by late afternoon or early evening. There may be a few showers along this cold front, but no significant precipitation is expected. However, temperatures will drop significantly behind the front, and winds will increase as well, marking an end to summery weather, at least for now.
10°C / 4°C
Mainly cloudy with showers
Tuesday will be a nasty day. High temperatures will struggle to reach double-digits and there will be a breezy north wind. To add insult to injury, we may also see some showers throughout the day, just adding to that nasty fall feel. This will be our first taste of fall weather since, well, last fall!
12°C / 2°C
Mix of sun and cloud
Wednesday will be another cool day in southern Manitoba. High temperatures in the low double digits are expected, with a breezy north wind once again.
After reading about the gloomy weather above, you’re probably hoping this isn’t it for summer…well, all hope is not lost, at least not yet! Long range models suggest that we may return to a more summery pattern at some point in the second half of September. Let’s hope the long range forecast is correct!
More unsettled weather is on the way as another generally unstable day gives way to the passage of a low pressure system and associated cold front that will finally result in a shift in the larger-scale weather pattern.
30°C / 18°C
28°C / 16°C
Mainly sunny; evening thunderstorms likely
25°C / 12°C
Generally unsettled weather will be in place over Southern Manitoba today as an unstable air mass continues to preside over the region. Shower activity will likely continue to remain elusive here in Winnipeg, but elsewhere, particularly northwards into the Interlake may see a few showers or thundershowers today. It will be hot with high temperatures near 30° combining with dewpoint values near 20°C making it feel more like the upper 30’s. Temperatures will dip just below the 20°C mark overnight under mainly clear skies.
Saturday will be another hot and humid day with plenty of sunshine. Increasing cloud in the afternoon ahead of an advancing cold front will restrain the daytime high to a couple degrees cooler than today. Winds will be the strongest they’ve been in a while, strengthening to 30-40km/h out of the south by late in the afternoon.
A line of showers and thunderstorms will develop along a cold front stretching from the northern Interlake into southwestern Manitoba late in the day and gradually push eastwards through the evening. It’s very likely that most places in the Red River Valley, Winnipeg included, will see some shower or thunderstorm activity as the front passes through. Rainfall amounts will be quite variable; it looks like 5 to 15mm will be fairly common, however higher amounts will be possible in thunderstorms. Skies will clear behind the cold front with temperatures dropping to the mid-teens.
Sunday will be a beautiful, albeit cooler, day. Southern Manitoba will see just a few clouds and a high near 24 or 25°C. Much of the humidity will be flushed out by the cold front, so it should also be a much more comfortable feeling day as well. There may be a slight chance of some isolated shower activity on Sunday night as a weak disturbance ripples southeastwards across the province. Temperatures will drop into the low teens on Sunday night.
Unsettled weather will mark the start of the last weekend of July, but conditions will improve for a rather pleasant end and persist into a fairly dry and seasonal start to next week.
Friday: Thunderstorms Possible
25°C / 15°C
Chance of showers or thunderstorms
Today is off to a cloudy start with a few showers likely through the Red River Valley as the remnants of the overnight activity push off to our east. Skies will remain mostly cloudy until the cold front that brought copious amounts of severe weather to Saskatchewan yesterday pushes through the Red River Valley early this afternoon.
As that cold front moves eastwards, it’s likely that more thunderstorms will fire up along it. Dewpoints in the upper teens will combine with daytime highs in the mid–20’s to produce MUCAPE values as high as 2000J/kg ahead of the front. Shear will be marginal with only around 25–30kt of surface-to–500mb bulk shear and the vertical wind profile isn’t particularly favourable for severe weather. The cold front will be enough of a trigger, although it will be weaker than yesterday and not offer nearly as much forcing as it did then.
As a result, thunderstorms will likely fire up somewhere in the central or eastern Red River Valley and push into the Whiteshell and far SE Manitoba this afternoon. At this point it doesn’t look like there will be an organized severe weather threat, but we’ll be taking a look a little later this morning to assess whether or not the severe threat needs upgrading.
Other than the storms, the day will be pleasant. Before the cold front passes the Red River Valley will be under a relatively light southerly or southeasterly wind. It will be fairly humid and temperatures in the low 20’s until the passage of the front, after which westerly winds at 30–40km/h bring in much drier air. The afternoon sunshine should help our daytime high climb to around 25°C.
Temperatures will drop to around 14°C under clear skies and light winds tonight.
24°C / 13°C
Mainly cloudy with widespread showers
Tomorrow will be the least pleasant day of the next few. A strong upper-level low will slide across Southern Manitoba through the day, producing widespread showers underneath it. There may be a few isolated thunderstorms, but for the most part most areas in Southern Manitoba will be seeing a fairly wet day. Winds will generally be 20–30km/h through much of the day, shifting from southwesterly or westerly to northerly through the day and overnight.
Skies will begin to clear overnight as the temperature drops to around 13°C.
24°C / 13°C
Sunday will likely start off with some low cloud trapped in the boundary layer making for mixed to mostly cloudy skies. As the temperature rises through the morning, the clouds will gradually break up leading to a mainly sunny afternoon with some scattered clouds. Highs will be around the 24–25°C mark and temperatures will drop to around 13°C once again on Sunday night.
This pleasant weather will continue through the first half of next week. Another strong ridge is forecast to build into BC/Alberta, which will keep temperatures seasonal and the weather dry.
Full discretion: I’m writing this on Thursday evening, and still unsure on how much of Thursday night’s convective activity will survive to the Red River Valley. ↩
Seasonal highs in Winnipeg right now are around 26°C. Seasonal lows are around 13°C. ↩
After enjoying a well above-normal –2°C daytime high on Monday, things are set to plunge back into the deep freeze as an Alberta Clipper low pressure system tracks into Ontario and allows a new supply of very cold Arctic air to surge southwards across the Prairies.
A potent Alberta Clipper will move through Manitoba today with the bulk of it’s snow falling along a line from Flin Flon through Norway House and Beren’s River where anywhere from 4–10cm can be expected. Further south, we’ll see light snow through the Parkland and Interlake through much of the day, but the snow won’t start in earnest until the afternoon along and south of the Trans-Canada Highway when the cold front associated with this system moves through.
And what a cold front it is! Yesterday saw genuine flash-freezes in the high plains of the Rockies; Dawson Creek, BC had it’s temperature fall from +5°C to –16°C in just 3 hours. In Grand Prairie, AB temperatures plummeted similarly, with temperatures falling from +5°C to –15°C in just 3 hours as well. It’s this intense blast of arctic air which will help this system produce snow despite the fact it is lacking considerable moisture.
While temperatures won’t be set to plummet quite so dramatically further east in Manitoba, we’ll certainly see the cold air return with a blast. We’ll be dealing with snow, wind, blowing snow and bitterly cold temperatures/wind chill by the end of the day today. Here’s what you can expect:
Snow: We’ll likely see scattered light flurries through the morning and early afternoon. Marginally more organized snow will try to push in through the afternoon along the cold front, but the system will have difficulty producing much snowfall anywhere other than along the northern edge of the track of the low pressure system. By the time things taper off this evening, anywhere from just a trace of snow to 2–3cm will likely have fallen in Winnipeg & the Red River Valley.
Wind & Blowing Snow: Winds will remain fairly light through the day until the passage of the cold front early this afternoon. Behind the front the winds will flip to the northwest and pick up strength to 30–40km/h with gusts as high as 60km/h. This wind will couple with the loose snow on the ground and the falling snow to produce widespread blowing snow through much of the Red River Valley. The worst areas for blowing snow will be the western and central RRV on any west-east running roads, including the Trans-Canada Highway between Winnipeg & Portage la Prairie. If you have plans to travel west on the Trans-Canada Highway today, be prepared for slippery roads with snow and blowing snow producing very poor visibilities.
Falling Temperatures/Wind Chill: Temperatures will fall quite aggressively behind the cold front with temperatures dropping from our daytime high of around –9°C to an overnight low of around –26°C. The cold temperatures coupled with the wind will produce wind chill values near –35 through the overnight hours.
The Remainder of the Week
-21°C / -28°C Sunny & cold.
The remainder of the week through the beginning of next week will be marked by the presence of yet another significant Arctic air mass entrenched over the Prairies. We’ll see mainly sunny skies on Thursday with light winds but temperatures will be very cold. Our high will only climb to around –22 or –21°C before plummeting back down to –28 or –29°C for our overnight low on Thursday night.
-17°C / -25°C Some afternoon cloud.
Temperatures will climb a little higher on Friday as a very weak disturbance ripples down the northwest flow, spilling a little bit of cloud across Southern Manitoba by the afternoon hours. The temperature will climb up to around –17°C and we’ll see the temperature drop to around –25°C on Friday night.
Things look clear and cold for the weekend. Another shot of Arctic air will push into the Red River Valley bringing another batch of bitterly cold temperatures and overnight lows near –30°C.
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