Warm Weather Continues

Above-normal temperatures[1] will continue through the remainder of the week as a southwesterly flow aloft continues to pump relatively mild Pacific air over the Prairies.

Wednesday
17°C / 8°C
Increasing cloud with a chance of showers

Thursday
15°C / 7°C
Mainly cloudy

Friday
16°C / 5°C
Some morning cloud, then sunny

Unsettled Wednesday

Today will be the most unsettled day of the week thanks to a (very) weak cold front pushing eastwards across the Red River Valley today. A fairly sunny start to the day will become more mixed by mid-day with a slight chance of shower activity in Winnipeg mid-day into the early afternoon. It seems most likely that the activity will remain to the east of Winnipeg, with showers or even thunderstorms almost a certainty in the Whiteshell southwards to the US border.

Precipitation forecast for this afternoon from the Canadian RDPS model.
Precipitation forecast for this afternoon from the Canadian RDPS model.

The American NAM weather model has been an outlier for several runs in a row, producing a fairly potent band of showers and thunderstorms over the western Red River Valley and pushing eastwards through the day. Given the weak surface forcing, mediocre moisture and the rate and evolution of the upper-level destabilization, it seems that the NAM is probably over-doing things and not a likely forecast. It’s worth mentioning here as an outside possibility, though, given its consistency in producing that outcome.

Other than the showers, strong southerly winds at 40 gusting 60km/h will taper off this afternoon behind the weak cold front as they shift to westerly at around 20km/h. The temperature will climb to around 17°C today.

Skies will clear out this evening as the temperature drops near 8°C for the overnight low.

Pleasant End to the Week

Thursday and Friday will both be pleasant fall days – especially for late October. Dry weather will be the name of the game for both days with highs in the mid-teens and fairly light winds. Some cloud will push across the Red River Valley on Thursday night but otherwise things will be mainly sunny/clear. The temperature will dip to around 6 or 7°C on Thursday night and a bit cooler – near 5°C – on Friday night.

Heading into the weekend, the weather continues to look pleasant with highs in the teens, no real threat of rain and plenty of sunshine. Enjoy!


  1. Normal daytime highs for this time of year sit around the 8°C mark.  ↩

October Starts By Heading into Chilly Weather

Temperatures will be on the slide as a low pressure system bringing unsettled weather today draws in cooler air behind it, plunging southern Manitoba into yet another spell of unseasonably cool weather.

Wednesday
17°C / 10°C
Cloudy with a few showers

Thursday
16°C / 5°C
Mainly sunny, showers likely in the evening

Friday
10°C / 1°C
A few sunny breaks, otherwise mainly cloudy with light showers

Wednesday

Today will be a mainly cloudy day here in Winnipeg with rather pleasant temperatures – highs will be around 16 or 17°C – alongside a brisk southerly wind to 30–40km/h. The warmer temperatures are thanks to a strongly wound-up low pressure system lifting northwards near the Manitoba-Saskatchewan border. It will spread an area of rain through Manitoba, but the bulk of it should be isolated along the main deformation axis of the system, sliding northwards through SW Manitoba and Parkland Manitoba into the northern half of the province. Scattered showers will likely be seen through the Red River Valley, but it doesn’t seem like much organized precipitation will develop; as such, rainfall amounts should remain fairly low over the region.

Total precipitation forecast by the RDPS from 7AM to 7PM today.
Total precipitation forecast by the RDPS from 7AM to 7PM today.

Skies will remain mostly cloudy this evening with a chance for some shower activity continuing until around the middle of the night. Clearing will begin afterwards as we head to a low of around 5°C.

Thursday

Thursday will actually be quite a pleasant day; most of the cloud cover should be off to our east leaving us with quite a bit of sunshine through the day as we head to a high once again around 16°C. By late afternoon, though, skies should begin to cloud up in advance of a potent shortwave barreling down in the northwesterly flow behind today’s system. Showers will develop under the shortwave as it progresses southeastwards with much of the Red River Valley seeing some amount of rainfall before 9PM or so. There is a slight chance of seeing some lightning or small hail in some of the shower activity if it manages to develop intensely enough.

A simulated RADAR image from the NAM depicting the potent shortwave moving through on Thursday.
A simulated RADAR image from the NAM depicting the potent shortwave moving through on Thursday.

A brief reprieve will be in store for the middle of the night, but more shower activity is expected to move through later overnight into Friday morning on the back-side of the shortwave. The temperature will dip to around 5°C.

Friday

Friday will start off cloudy with a few remnant showers from the shortwave pulling off to the east. The shower activity should move off relatively quickly, but there’s a slight chance things will linger a little longer if the shortwave stalls out over SE Manitoba. Afterwards we’ll be entrenched in a northwesterly flow with Arctic air spilling southwards into the province. Our temperature will top out around 10°C with some lake-effect drizzle/showers likely in the lee of the lakes.[1]

The Arctic air mass moving in will be the coldest air mass of the season so far in Southern Manitoba. Temperatures will drop to 0–2°C on Friday night under mainly clear skies and a brisk northwesterly wind. Some areas will see cloud streaming off of the lakes, again though where that cloud goes will depend exactly on which way the wind blows.

Cool Weekend Ahead

This weekend will be a cool one as cold Arctic air entrenches itself over the province. Daytime highs will sit in the low teens with overnight lows in the low single digits, perhaps even dipping just below 0°C. Sunday may bring the chance for some shower activity pushing in from the east, but things look rather uncertain at this point.


  1. The wind direction makes it look unlikely that the lake-effect activity will push into Winnipeg; keep in mind that which areas see lake-effect precipitation is extremely sensitive to wind direction.  ↩

Warm & Unsettled Weather

The weather over the next couple days will be two things: warmer than normal for this time of year and somewhat unsettled. While no major rain-makers are expected, a couple rounds of showers will make for some damper spells. Fortunately, daytime highs near 20°C will be above the seasonal 17°C through the weekend!

Friday
22°C / 12°C
Mixed skies; chance of showers or thunderstorms

Saturday
20°C / 10°C
Mixed skies; chance of showers or thunderstorms

Sunday
20°C / 10°C
Mainly sunny

Today will bring mixed skies to Winnipeg as a broad trough of low pressure works its way across the province. There will be a slight chance of showers this morning if any of the overnight activity manages to linger on and/or push far enough north, however nothing significant is expected. We’ll see mixed skies heading into the afternoon with a high near 22°C with winds tapering off to light.

The RDPS is forecasting a line of thunderstorms along the advancing cold front this afternoon.
The RDPS is forecasting a line of thunderstorms along the advancing cold front this afternoon.

Later in the afternoon the threat of showers or thunderstorms returns as a weak cold front begins slumping southwards. Severe weather doesn’t look likely, although if stronger thunderstorms manage to develop some marginally severe hail could be a possibility.[1]

Skies will clear out a bit in the evening and we’ll be left with partly cloudy skies on our way to a low of around 12°C.

Saturday will start off with just a few clouds around. We’ll warm up to around 20°C for an afternoon high with winds gradually increasing out of the west-northwest to around 20–30km/h. By mid-to-late afternoon the threat for shower or thunderstorm activity will increase as a shortwave sliding down in the northwest flow aloft begins triggering activity over Parkland Manitoba and the Interlake. That activity will slide southeastwards through the afternoon into the evening with scattered showers or thunderstorms looking fairly likely.

This map of a feature called vorticity – essentially a measure of spin – shows a potent shortwave moving across Southern Manitoba on Saturday afternoon.
This map of a feature called vorticity – essentially a measure of spin – shows a potent shortwave moving across Southern Manitoba on Saturday afternoon.

Some thunderstorms may be surprisingly strong given the relatively meagre convective indices for the day. The key will be the favourable storm-relative winds in place. Suitable turning will be in place that it’s possible — not necessarily likely, but possible — for an isolated supercell or two to develop with strong winds and large hail being the primary threats.

Skies will clear out on Saturday night as we drop to around 10°C.

Sunday will be a nice day with not a whole lot to say about it! A ridge of high pressure moving into the province will bring clear skies and relatively warm temperatures with a high near 20°C. The temperature on Sunday night will drop to around 10°C.


  1. Environment Canada considers severe hail to be 20mm or larger in diameter.  ↩

Week to End with Summer-Like Weather

Patience will be rewarded heading towards the end of the week as above-normal temperatures[1] are poised to return to Southern Manitoba thanks to a low pressure system that will push across the Central Prairies. In addition to the warmer weather, the chance for some wet weather, possibly even thunderstorms, will make a return as well.

Warmer air is forecast to spread eastwards across the Southern Prairies over the next 48 hours.
Warmer air is forecast to spread eastwards across the Southern Prairies over the next 48 hours.
Wednesday
14°C / 3°C
Mainly cloudy & cool; clearing in the afternoon

Today will be the coolest day of the next few as we remain on the periphery of a large pool of Arctic air. Plenty of stratus cloud will persist in Winnipeg until this afternoon; afterwards we’ll see clearing skies and a high temperatures near 14°C. Another chilly night lies ahead with temperatures dropping to the 3 or 4°C mark under continued clear skies.

Thursday
20°C / 16°C
Increasing cloudiness with a breezy southerly wind

Thursday will mark our entry into warmer weather. Gusty southerly winds will develop ahead of a warm front that will gradually push eastwards through the day. Winds will peak at around 30–40km/h with the potential for gusts to around 50km/h. Much of the day looks fairly sunny which will help temperatures climb to around 20°C by late in the afternoon, but by mid-to-late afternoon clouds will noticeably begin thicken up.

The potential for thunderstorms returns Thursday night, but it’s conditional and will be mainly confined to southwestern Manitoba. Substantial mid-level instability will couple with a strong low-level jet (LLJ) in the evening to attempt to produce thunderstorms. While many severe weather parameters output by various models look fairly impressive, there are a few concerns I have with development, somewhat related to each other:

  1. Even lifting from the low-level jet, convection looks capped. If lift is strong enough to break through the cap and taps into the mid-level instability, then strong to severe storms could be possible, but…
  2. Synoptic lift looks uncertain. While the LLJ is forecast to be quite strong at 25–35kt, deeper synoptic lift looks uncertain. Some models hint at a shortwave rippling through the region on Thursday evening, which could help initiate thunderstorms if true.
The NAM is forecasting winds in excess of 40kt at 850mb over Southern Manitoba on Thursday evening.
The NAM is forecasting winds in excess of 40kt at 850mb over Southern Manitoba on Thursday evening.

If thunderstorms did manage to initiate over southwestern Manitoba, they would have a chance of becoming severe, with the main threats being large hail and strong winds. As the system pushes eastwards overnight, the chance for showers or thunderstorms will spread into the Red River Valley. The thunderstorm potential will diminish as the system moves eastwards.

With all the cloud, potential precipitation and breezy winds moving through overnight, temperatures will remain fairly mild, only dipping down to the mid-teens.

Friday
22°C / 9°C
Chance of morning showers; afternoon clearing

Friday will continue the pleasant weather. A slight chance of showers may persist into the morning from Thursday night, but skies should quickly being to clear out, leaving us with partly cloudy to mixed skies for the remainder of the day. Daytime highs will climb into the low 20’s without too much wind to worry about.

Temperatures will drop just under 10°C on Friday night under mainly clear skies.

The Weekend Ahead

The coming weekend looks great! Mostly sunny skies will dominate through the weekend with daytime highs continuing to sit in the low 20’s and overnight lows in the mid-to-high single digits. It will be a beautiful late-September weekend, so get out and enjoy it!


  1. Normal temperatures in Winnipeg for this time in September are around 18°C for high temperatures and 6°C for low temperatures.  ↩