Turning Up The Heat

A long-deserved taste of summer is in store for Southern Mantioba as the temperature rises with little chance of precipitation until the end of the week.

An upper-level ridge of high pressure building into the region will tap some of the record-breaking heat over British Columbia and slowly spread it eastwards over the Prairies. While we won’t see temperatures nearly has hot as the 40°C+ they’ve seen in B.C., temperatures will push towards the 30°C mark by week’s end. While some scattered thunderstorm activity is possible Thursday night, in general it looks like it will be quite dry in many places over the next couple days. With all the heat, it does look like a more organized thunderstorm threat is set to re-develop on Friday in the Red River Valley.

26°C / 15°C
Mainly sunny

29°C / 17°C
Mainly sunny

30°C / 16°C
Chance of showers or thunderstorms.

Today will be a beautiful summer day with a seasonal high of 26°C and relatively light winds out of the south at 15-25km/h. Tonight will be mainly clear with light winds and a temperature dropping to around 15°C.

Thursday will see the heat really begin to show up with temperatures climbing into the upper 20’s to just over the 30°C mark across much of Southern Manitoba. Winds will be out of the south or southwest at 20-30km/h. By evening, a weak cold front will move in from the northwest and will likely spark of some scattered thunderstorm activity over Western Manitoba that may slowly spread SE into the Red River Valley overnight. At this point, it doesn’t appear that there will be a significant threat of severe thunderstorms with Thursday’s activity.

Thunderstorm Threat Returns Friday

Friday will start off with a slight chance of showers or thundershowers if Thursday night’s convection manages to make it this far east, but then see temperatures once again approach 30°C with winds building out of the south to around 30km/h. The cold front that moved in Thursday will lift back northwards ahead of another approaching low pressure system and the associated incoming upper-level trough will likely generate thunderstorm activity through the Red River Valley on Friday afternoon into the evening.

GFS-forecasted upper-level winds (500mb) for Friday evening.
GFS-forecasted upper-level winds (500mb) for Friday evening.

With in excess of 1500J/kg of CAPE, 30-40kt of bulk shear, fair surface moisture and the strong dynamical forcing of the upper-level trough coupled with enhanced lift in the right entrance region of the jet, it looks like there will probably be a slight risk for severe thunderstorms. At this point, the main threats look to be wind and hail, although if things continue to trend in a similar direction, the Red River Valley could see one of it’s first organized tornado threats of the year. We’ll be keeping a keen eye on things and have updates later in the week.

Weekend to Bring A Break From The Heat

Slightly cooler weather will move in this weekend behind a low pressure system forecast to move through tonight and tomorrow. In addition to the cooler temperatures, this system will bring a chance of rain and thunderstorms to the Red River Valley.

Tonight & Tomorrow


27°C / 18°C
Increasingly cloudy; risk of a thunderstorm late in the afternoon into the evening. Humid.

We’ll see gradually increasing cloud today as the surface trough associated with a low pressure system pushing into the northern Interlake approaches. There may be some ongoing thunderstorm activity along the trough this morning as it pushes through SW Manitoba and that threat will move eastwards into the Red River Valley by the late afternoon or early evening. A southerly wind ahead of the trough coupled with a capping inversion will draw moisture northwards once again and trap it near the surface, making for another hot, sticky day here in Winnipeg. Our high temperature will only climb to around 27 or 28°C, though, thanks to the increasing cloudiness through the day. That hot, humid weather will bring the threat for thunderstorms – potentially severe – late in the afternoon into the evening hours. At this point, it seems like somewhere between 8PM and 11PM seems like the most likely time for seeing any potential storm activity. After that we’ll see our temperature drop to around 18°C under a partly cloudy sky.


25°C / 12°C
Becoming cloudy, good chance of showers or thundershowers. Humid again.

Saturday will be another humid day as we remain in the moist air mass ahead of the cold front. We’ll see a fairly good chance of showers or thundershowers beginning later in the morning and through the afternoon. Skies will start off as a mix of sun and cloud but should become fairly cloudy in the afternoon as things become more unstable with the approaching cold front. We’ll see a high of around 25°C which will mark the last day in our hot, muggy air mass. The threat for showers or thunderstorms will persist until the cold front passes.

500mb Winds for Saturday Afternoon

500mb winds forecast by the NAM show an intense upper-level low pushing into Southern Manitoba which may be the catalyst for showers and thunderstorms on Saturday afternoon and evening.

The cold front will push through overnight, bringing northwesterly winds that will clear out much of the moisture and drop us to a comparatively cool 12°C for an overnight low with clearing skies.

Sunday & Holiday Monday


23°C / 8°C
Sunny. Cooler and much less humid.

25°C / 13°C
Sunny and warm.

Sunday and Labour Day Monday look absolutely beautiful. Sunday will be slightly cool with a high of only around 23°C and lead into a chilly night with a low dropping into the single digits bottoming out around 8°C. The heat starts to return on Monday with sunny skies continuing as we climb to a mild 25°C.

The Trend Next Week

Looking further into the week, it looks fairly nice overall as the upper ridge begins rebounding back northwards into the Prairies. Highs will push back into the upper 20’s with humidity staying fairly low until late in the week. Things look fairly dry through the first half of the week, with a few weak disturbances bringing the threat for isolated-to-scattered thunderstorms late in the week. For the most part, though, it looks to be a beautiful, warm week. Summer may be late, but it doesn’t look like it’s going anywhere soon!

A Bit of A Mixed Bag For The Long Weekend

Fairly nice weather is ahead for the long weekend with plenty of sunshine and hot temperatures. The only chance for rain will come on Saturday night as a low pressure system passes through the Interlake.

GFS Precipitation for Saturday Night

12 hour rainfall accumulations from the GFS for Saturday night, depicting the showers expected to develop over southern Manitoba.

Temperatures will climb to 30°C today across the Red River Valley as southerly winds build over the region and advect in slightly warmer air. We’ll see an overnight low of around 15°C with clear skies tonight. Tomorrow will likely be a few degrees cooler than today as cloud cover works it’s way into the area in the afternoon. We’ll see slightly stronger winds closer to 30km/h, develop by the afternoon as a low pressure system begins to push across Saskatchewan.

A strong low-level jet (LLJ) is forecast to develop on Saturday evening. Current consensus is that a 40kt LLJ will develop over central North Dakota and slowly push eastwards overnight. An area of showers and thundershowers look to develop on the nose of the LLJ, mainly through areas between the International Border northwards towards Riding Mountain Provincial Park eastwards across the Interlake. There is one great uncertainty with this system, though: Isaac. The storm previously known as Hurricane Isaac will be pushing northwards towards Iowa before shifting it’s track eastwards on Sunday. The moisture required for us to be able to see precipitation on Saturday night sits along a narrow boundary left behind across the Northern US. As it stands now, the LLJ that forms tomorrow evening is supposed to tap into that pool of moisture and transport it northwards into the RRV. Should the track of Isaac change significantly between now and then, the location of the moisture pool may change and move to an area that the LLJ wouldn’t be able to tap into. Should that happen, it’s unlikely we’d see much more than scattered showers over the RRV with little accumulation.

Things will clear out early Sunday morning and we’ll have some sunshine before a few clouds bubble up in the afternoon. We’ll have a cooler day with a high of 25°C.

Holiday Monday looks like a beautiful day with plenty of sunshine and a high once again near 25°C and breezy westerly winds gusting to 40-50km/h.

Hot Weather Returns

After a period of cool weather over the last while, warmer conditions are set to return.

30C temperatures are expected on Tuesday in Southern Manitoba

The NAM model is predicting that Southern Manitoba will see temperatures of 30C or higher on Tuesday

A ridge of high pressure will build over the Prairies this week, allowing for some of the warmest weather we’ve seen this August to develop. Monday will be a pleasant day, with high temperatures in the mid to upper twenties. By Tuesday many areas should see their first 30C readings this month, as warmer air pushes in from the west.

The ridge will begin to break down on Wednesday and Thursday as a series of impulses move in from the Pacific. These impulses with have one or more low pressure systems associated with them, causing some unsettled weather to start developing over the Prairies later this week. It looks like an easterly flow will develop over Southern Manitoba on Wednesday out ahead of an approaching low. Depending on how the frontal features setup on Wednesday we may or may not see another 30C day. At this point it looks most likely that Wednesday will have temperatures in the upper twenties, rather than thirty, but there is the potential for warmer weather. On Thursday we may see our first risk of thunderstorms in a while as a strong southerly flow draws up more humid air from the south ahead of an approaching low pressure system.

As we move toward the weekend weather models show a series of fairly strong low pressure systems moving through our region. Should these systems develop more or less as predicted it would likely mean a rainy and cool last weekend of August.