Cooler Weather Settling In

After a windy day yesterday, Southern Manitoba will see cooler weather through the remainder of the week as a fairly seasonal air mass sits anchored over the region. While cool, things will remain dry as any showery weather remains locked up in Central Manitoba & the Northern Interlake.

The Next Few Days

Wednesday

16°C / 3°C
Some cloudy periods.
Thursday

16°C / 3°C
Partly cloudy.
Friday

10°C / 2°C
Increasing cloud, cooler.

Today and tomorrow will be essentially carbon copies of each other. Highs will sit around 16°C with overnight lows near 3°C. Winds are expected to be fairly light both today and tomorrow. Both days will have some cloud around; today we’ll see some cloud pushing up from North Dakota through the Red River Valley while tomorrow we’ll see some cloud slumping southwards from the Interlake. While there may be some light shower activity with the cloud pushing southwards from the Interlake, at this point the entirety of it is expected to remain west of the Red River Valley in the Riding Mountain region slumping southwards into SW Manitoba.

Things will cool off a bit on Friday in the Red River Valley as an intensifying low pressure system in South Dakota/Minnesota draws cooler air from the north into the Red River Valley through the day. Any rain this system produces will remain south of the Canada/U.S. border in the Dakotas and Minnesota. We’ll see some cloud push into the Red River Valley through the day thanks to this system. Exactly who will see cloud and who won’t will be tough to call; the cloud will likely have quite a sharp edge thanks to a strong deformation zone. It will be fairly safe to say that places such as Steinbach and areas SE will end up overcast by day’s end while areas west of Winnipeg, such as Portage la Prairie, will likely remain fairly sunny. Here in Winnipeg we’ll likely sit somewhere near the edge of the edge of the cloud by day’s end.

Looking to the Weekend

The weekend looks fairly quiet over much of Southern Manitoba. Benign weather will dominate over SW Manitoba, things should remain fairly calm over the Red River Valley and the SE portion of the province will see a shot of getting some rain.

An area of rain looks to push northwards out of North Dakota and Northern Minnesota as a developing low lifts NE out of Minnesota on Friday night. The area of rain will have a very sharp edge on it’s northwestern flank thanks to the aforementioned strong deformation zone. Most models are keeping all of the rain in the United States, however some higher-resolution long-range and medium-range models are starting to creep the system a little further west and introduce some rain activity into SE Manitoba on Saturday, likely through the Sprague region. At this point, I’d say that the region has just a slight chance of some rain.

The Red River Valley looks to remain completely clear of the rain for this system with mostly clear skies and cool-to-seasonal temperatures.

October Won’t Have a Scary Start

October won’t start off with any scary weather, but I can guarantee the month will end on a frightening note!

Tuesday Will be a Very Windy Day in Southern Manitoba

Monday

Monday

Mix of Sun and Cloud. Chance of Showers Late.
22°C / 8°C

Today will be a nice day in Southern Manitoba. Temperatures will be in the low twenties, under a mix of sun and cloud. The wind will be breezy and from the south-west. A cold front will push through Southern Manitoba on Monday night, setting up a cooler Tuesday. There may also be some light rain showers associated with this front, but it will be a hit and miss type of rain event.

Tuesday and Wednesday

Tuesday

Increasing Cloudiness
17°C / 4°C
Wednesday

Mix of Sun and Cloud
15°C / 6°C

The first day of October will neither be really good, nor really bad. On the one hand it will be a seasonably warm day, with temperatures in the mid to upper teens. However, it will also be a very windy day, with westerly winds of 40-50km/h gusting to 60-70km/h (winds may reach 60km/h gusting to 80km/h on a localized basis). Unfortunately, that strong wind will make conditions much less pleasant than they otherwise would be.

Wednesday looks to be much less windy than Tuesday, but it will still be on the breezy side. Temperatures will be in the mid teens, with a westerly wind of 20-30km/h gusting to 40-50km/h.

Long Range

The long range forecast is looking more October-like. Another cold front is currently forecast to move through Manitoba on Wednesday night, bringing in cooler conditions to end the week. Models are also hinting at a strong low pressure system passing near or just south of Manitoba later this week. Should this system take a more northern track, it could impact Southern Manitoba…but it’s too early to say.

Uncertain Weekend Ahead

A complicated series of weather disturbances pushing across Southern Manitoba will provide a sensitive forecasting challenge as multiple batches of narrow bands of rain with sharp edges push across the Red River Valley and areas east.

This satellite shot shows the development of the next system in Colorado that will move along the existing frontal boundaries and bring more rain to Southern Manitoba.

This satellite shot from last night shows the development of the next system in Colorado that will move along the existing frontal boundaries and bring more rain to Southern Manitoba.

Friday

Friday

17°C / 9°C
Mainly cloudy. Chance of showers.

Today will bring the most disorganized batch of precipitation as a weak low pressure system pushes out of ND/MN into the Lake of the Woods area. This seemingly weak feature will be coupled with a 500mb jet streak that will advect across the Red River Valley and the Whiteshell.

The upper-level jet streak will advect over a quasi-stationary front aligned north-south over the the Red River Valley. The convergence along the front, when combined with the lift associated with the jet streak, will likely produce some isolated showers and starting midday and lasting through the evening hours. The showers will be tied very tightly to the jet, so depending on where that jet ends up exactly will dictate where the potential lies. If things shift east slightly, the showers could easily only happen over SE Manitoba (in the Sprague area) or we could even see no showers at all.

It seems fairly likely there will be some isolated to scattered showers, though. With mainly cloudy skies the temperatures will struggle to warm up and we’ll likely see a high of only – and perhaps this isn’t all that bad since it’s close to seasonal for this time of year – around 17°C. Winds won’t be much of an issue today.

We’ll see plenty of cloud tonight alongside that chance for showers in the evening with temperatures dipping to around 9 or 10°C.

Saturday

Saturday

15°C / 5°C
Cloudy. Slight chance of rain.

Saturday will be another rain event for Southern Manitoba as the upper trough that has been bringing the unsettled weather to the Prairies over the last week finally begins pushing eastwards. A low pressure will eject out of the upper trough on Friday night and rapidly lift northwards towards the Lake of the Woods and intensify. Rain will push into southeastern Manitoba on Friday night with a sharp western edge as the rain stays tightly associated with a strong upper-level jet. There’s some uncertainty on exactly where this jet is going to set up and how it will move through the day; some models keep the entirety of the rain over the SE RRV and Sprague/the Whiteshell while other models dig the upper trough a little more and pull the jet westwards, backing the rain into Winnipeg.

12hr. QPF panel from the RDPS model showing forecast rainfall accumulations through the daytime on Saturday.

12hr. QPF panel from the RDPS model showing forecast rainfall accumulations through the daytime on Saturday and the position of the low and associated fronts at day’s end. Winnipeg sits on the very edge of the main area of precipitation.

At this point, it seems like there are two rainfall scenarios for Winnipeg:

  1. The rain advects into Southern Manitoba further west than currently forecast and Winnipeg sees some rain (potentially somewhat heavy) early Saturday morning before it pulls off to our east and sits over SE Manitoba for the rest of the day.
  2. The main band of rain remains east of Winnipeg with us potentially seeing some light shower activity through the day as we get brushed by the edge of the system. Light winds and ample moisture may result in some on-and-off drizzle through the day.

While there is a chance that the main rain band may back further west and we’ll see a rainy day, I don’t think that outcome is very likely. It will be a cool, damp day with a high of only around 14 or 15°C. Clouds will clear out in the evening/overnight period as we drop to around 5°C for a low.

Sunday & Beyond

Sunday

22°C / 10°C
Mainly sunny & warming up.

Sunday will bring much more pleasant weather as we see mainly sunny skies and a high in the low–20’s. It will mark the beginning of another stretch of fairly sunny weather with well above-seasonal daytime highs. We’ll see a low of around 10°C on Sunday night with clear skies.

The start of next week will bring sunny skies and temperatures climbing into the mid–20’s, as much as 10–11°C above the seasonal daytime high of around 14–15°C for this time of year!

Beautiful Start To Fall Continues

Our beautiful start to fall – a start that has seen two days in a row a full 9–10°C above normal – will continue with well above-normal temperatures continuing through the week. A powerful storm system moving into Saskatchewan will lead to more unsettled weather as we move towards the end of the week, but rain is far from guaranteed here in Winnipeg.

Wednesday

Wednesday

25°C / 16°C
A mix of sun and cloud; windy out of the south.

We’ll see another pleasant but breezy day today under a mix of sun and cloud as some patchy cloud cover moves eastwards from a powerful storm system taking shape over central Saskatchewan. Temperatures should climb to around 25°C this afternoon as gusty winds pick up to 30–40km/h out of the south. The winds will let up a little bit overnight but will still be noticeable which, when combined with increasing cloudiness, will conspire to keep our overnight low around a balmy 16°C – which is coincidentally the average daytime high for this time of year.

Thursday

Total accumulated rain from the GDPS on Thursday 12Z - 00Z.

12 hour rainfall accumluations depicting rainfall during the daytime on Thursday. Under 2mm is forecast by the GDPS for Winnipeg.
Thursday

24°C / 12°C
Cloudy with gradual clearing. Chance of showers midday through the afternoon.

Thursday will bring mostly cloudy skies as the Saskatchewan storm edges eastwards slowly. While showers will push in over Western Manitoba, here in Winnipeg we’ll see just a slight chance of seeing some shower activity. The chance will start midday and last through much of the afternoon, but if we do get any rain it shouldn’t accumulate to anything significant.

The day will start mainly cloudy, but we should see mainly sunny skies by the evening as everything lifts off to the north. Our temperature will climb to around 24°C with winds around 30km/h diminishing through the afternoon. Thursday night will start with mainly clear skies but we’ll see increasing cloudiness by Friday morning as cloud streams in from the southwest ahead of yet another disturbance.

Friday

Friday

18°C / 7°C
Cloudy periods. Very slight risk of a morning shower.

We’ll see some cloudy periods on Friday as another disturbance spreads cloud ahead into Southern Manitoba. Our temperature will be a bit cooler; the daytime high is expected to hit around 18°C as a cold front pushes across the Red River Valley.

Friday night holds some promise of seeing some precipitation, which is rapidly becoming needed in Winnipeg. Only 4mm of rain has fallen in Winnipeg so far this September, not even 10% of the average of 45.5mm that falls in this month. The last significant rainfall in Winnipeg was the heavy thunderstorms that occurred through the morning of Sunday, August 18th which brought 15–30mm to the city. Since then, only 6mm of rain has fallen.

The GDPS is currently the only system that’s bringing rain into Winnipeg on Friday night, however there are some indications that other models could begin to fall in line with that thinking as well. Unfortunately, it’s going to be yet another system that has a very sharp cutoff on it’s edges. This system will be very sensitive to track, so we’ll be sure to keep an eye on things as they develop. Be sure to check back in the comments below for updates closer to the weekend.