Nice Start to the Week

This week will start out fairly nice, with the exception of some showers on Monday.

A weather system will bring showers to Manitoba on Monday



Mainly cloudy a chance of showers, then clearing.
21°C / 10°C

Today will be a mixed day weather-wise. Showers are likely in the morning as a strong upper-level jet stream induces lift over the area. These showers are expected to taper off by this afternoon, with clearing skies thereafter. Once skies clear, temperatures should warm into the low twenties.

Tuesday and Wednesday

Tuesday and Wednesday look to be fairly similar days in Southern Manitoba. Both days should be mainy sunny with temperatures in the mid twenties. The wind should be fairly light, making conditions ideal.


Mainly Sunny
25°C / 13°C

Mainly Sunny
25°C / 12°C

Late Week

The late week forecast is unclear at this point. A strong longwave trough[1] will come onshore late in the week. This trough may generate a series of thunderstorm days across the Canadian Prairies and Northern US Plains. At this point the location and timing of storms is not known, but more details on this situation will be available as the week progresses.

  1. A longwave trough is a large-scale dip in the jet stream that is usually associated with strong weather systems and/or severe weather outbreaks.  ↩

Mixed Weekend Ahead

The warm, mostly sunny weather of the past few days will give way to more unsettled conditions as a low pressure system anchors itself in Central Saskatchewan allowing a trough to sit over Southern Manitoba as a second low works it’s way across the Northern Plains of the United States. Showers will try to get going across Southern Manitoba but their coverage will be heavily limited by a lack of upper-level support over the region.


24°C / 12°C
Sunny with cloudy periods. Chance of showers or a thunderstorm in the afternoon.

We’ll start off with some lingering clouds this morning with a chance of a few scattered showers as the remnants of a weak cold front wash out over the Red River Valley. We’ll then see a bit of short-lived clearing before skies cloud up this afternoon once we get warm enough to get some convection going. There will be enough instability around to produce a few afternoon showers or perhaps even a weak thunderstorm or two. Lifted Index values will be sitting at only –1 or –2°C which represents only marginal instability and CAPEs agree with values only around 500–750J/kg.

With little forcing in the area, the most favourable area for showers or thunderstorms will be near subtle convergence features; in our case, that will mean near either the western escarpment of the Red River Valley or any lake breeze convergence lines that form to the north and northwest of the city. At the moment it’s looking like the most potential for a thunderstorm sits west of Winnipeg in the Red River Valley, but there’s certainly a chance we may see an afternoon thunderstorm here in the city. Aside from the potential showers & thunderstorms, it will actually be a fairly pleasant day. Winds will be fairly light through the day and we’ll be climb to a high near 24°C. Skies will clear tonight as we head to a low of around 12°C.

Saturday & Sunday


23°C / 12°C
Increasing cloudiness then a few showers or rain.

24°C / 12·C
Mix of sun and clouds. Showers likely southwest of Winnipeg.

After a sunny start, skies will cloud over on Saturday as a trough connecting a low pressure system in central Saskatchewan and a low pressure system pushing into the Dakotas. There will some showers ahead of the trough line that will push through the Red River Valley in the afternoon. Rainfall amounts won’t be anything significant, but a localized 5–10mm can’t be ruled out. We’ll see a high near 23°C and an overnight low once again sitting near 12°C under clearing skies. Sunday will be a mix of sun and clouds with showers likely south and west of the Red River Valley. The high for the day will be around 24°C with an overnight low into Monday morning of about 12°C once again.

Pleasant End to the Week

A pleasant second half to the week is on the way with near-normal temperatures and lots of sunshine. Daytime highs will sit near 22°C through the rest of the week with overnight lows around 10 or 11°C. Winds will remain light through today and tomorrow then start to pick up to 20–30km/h out of the south by Friday afternoon. Not a whole lot to say other than it will be quite pleasant!


21°C / 10°C
Mainly sunny.

22°C / 11°C

22°C / 11°C
Mainly sunny.

The Weekend

Looking ahead to the weekend, it’s looking more and more likely it will be showery with with a risk of thunderstorms. An upper low is forecast to track across Southern Manitoba on Saturday supporting two lows: one that will track through the Interlake region tied closely to the upper low and a second low pressure system that will track through North Dakota tied to the associated frontal wave[1].

Lifted Index for Saturday Afternoon from the GFS

Lifted Index for Saturday Afternoon from the GFS.

At this point, strong instability is forecast through the Northern Plains of the United States with LI values (shown above) near –10°C showing some fairly significant instability. CAPE values south of the border are also forecast to climb into the 2500–3000J/kg range.

Further north, instability is forecast to be sitting over Southern Manitoba, although the weaker LIs of only of only around –2°C mean that we’ll need stronger forcing to get any significant storms going; with the frontal wave in the US I’m inclined to say that we’ll see more cloudy/showery weather than the potential for any significant storms. Rainfall amounts shouldn’t really come close to the last two systems, although convection in the United States is expected to feed moisture northwards into the upper low and it will spread it out into a band of showery rain again. As the system passes through, more showers are expected on the back side on Sunday.

That’s all still a long ways out, though. We’ll keep an eye out and be sure to give more details by week’s end.

  1. The frontal wave of a system is it’s associated warm & cold fronts.  ↩

A Cool But Dry Start to the Week

Below-seasonal temperatures will persist through the beginning of this week but that gloomy news will be offset by the fact that we should see plenty of sunshine over the next couple days. A disturbance tracking through the Dakotas will bring a chance of showers for the Red River Valley on Wednesday as it pushes the coldest air out of the Red River Valley and pushes us back towards seasonal temperatures.

19°C / 6°C
Sunny. Increasing cloud overnight.
18°C / 7°C
Mainly cloudy. Chance of showers near the U.S. border.
16°C / 7°C
Clearing in the afternoon. Channce of showers near U.S. border.


We’ll see nothing but sun today as a ridge of high pressure dominates the weather over the Red River Valley. Daytime highs will sit near 18 or 19°C. We’ll have another cool evening tonight with lows dipping to around 5°C.

Tuesday & Wednesday

Cloud will begin to push in on Tuesday as a low pressure system begins to work it’s way into North Dakota. The chance for precipitation in Winnipeg is very minimal, but closer to the international border it’s more likely that a shower or two will be seen. A sharp cutoff is expected from accumulating rain to nothing, and while the models have been trending towards keeping all the rain on the US side of the border, it’s important to note that around 10mm of rain is forecast for areas only 75–100km south of the Canadian border.

GDPS Precipitation for Tuesday.

Rainfall expected through the day on Tuesday. A sharp cutoff is expected from the accumulating rainfalls in North Dakota and little-to-no rainfall in Southern Manitoba.

While just a few spits of rain is most likely for soaked communities in the southern Red River Valley, we’ll definitely be keeping our eyes on it. If the system ends up just a bit further north than forecast, areas such as Treherne, Morden, Gretna, Altona, Letellier & Emerson could see some light rain. For now, though, I’m expecting just a chance for a shower or two.

Rest of the Week

Heading through the rest of the week it looks like we’ll see couple of mainly sunny days on Thursday & Friday with temperatures climbing back to seasonal[1]. The weekend is worth keeping an eye on as another strong upper low is forecast to move into the region bringing showers and the potential for a few thunderstorms.

  1. The normal daytime high for Winnipeg at this time of year is around 22°C.  ↩