Warmer, Muggier, Unsettled Weather Coming Up

Temperatures will be on their way up as a warmer, more humid air mass begins moving in from the south, but ample cloud will keep sunshine relegated to “rare resource” status.

The cooler weather of the first half of the week is on it’s way out as a broad trough pushes across the Prairies. A southerly flow will spread through Saskatchewan and Manitoba today which will begin tapping into both warmer and more humid air pushing northwards through the American Plains.

The Canadian forecast model shows the muggy air expected to move in by Friday.
The Canadian forecast model shows the muggy air expected to move in by Friday.

The warmer and more humid air will, unfortunately, also result in more unsettled weather bringing plenty of cloud to the region. Multiple disturbances tracking into the region by week’s end will also result in the return of thunderstorm activity.

Wednesday
20°C / 14°C
Mostly cloudy with a chance of midday showers. Clearing overnight.

Thursday
25°C / 16°C
Increasing cloudiness in the afternoon. Chance of showers overnight.

Friday
26°C / 17°C
Mainly cloudy with showers or thunderstorms.

Another Cool, Cloudy Day

Today will be cool and mostly cloudy through much of the Red River Valley. A few sunny breaks may develop this morning, however with daytime heating more clouds will likely be generated to take their place. There is a slight chance of some showers in Winnipeg and the rest of the Red River Valley beginning late this morning through the afternoon, but anything that develops looks to be fairly light. The high today will be around 5°C below normal at 20°C.[1] Winds will gradually shift from northeasterly this morning to southeasterly by the end of the day, remaining relatively light throughout.

Skies should clear out a fair amount on Wednesday night as temperatures dip to a low near 14°C.

Warmer, Unsettled Weather Moves In

Thursday will be the transition day for the Red River Valley into a warmer, more humid air mass. The day will likely start off mostly sunny – or perhaps a high overcast – with winds out of the southeast increasing to 20-30km/h. The temperature should reach around 26°C, however more notable will the rising dew point[2] which should reach around 17°C by the end of the day. While not too high, the extra humidity will definitely be noticeable by the evening.

Total precipitation forecast by the GDPS for Thursday evening to Friday morning.
Total precipitation forecast by the GDPS for Thursday evening to Friday morning.

In addition to the rising humidity, cloud cover will spread into the Red River Valley from as a trough works its way into southwestern Manitoba. Showers and thunderstorms will be likely over southeastern Saskatchewan and southwestern Manitoba late in the afternoon and into the evening. Although it appears that the worst – and more likely to be severe – weather will remain in Montana and North Dakota, an isolated severe thunderstorm cannot be ruled out, particularly in SE Saskatchewan.

The afternoon storm activity will weaken after sunset but likely continue through the night pushing eastwards and northwards. There will be a fairly good chance of some shower or thundershower activity tomorrow night through most of the Red River Valley; no severe weather is expected at this point. Thanks to the more humid air, the overnight low will sit around 17°C.

Stormy Friday

Friday will mark a return to wetter weather as a low pressure system lifts northwards out of North Dakota through the Red River Valley, bringing with it a surge of warm, muggy air. Temperatures will climb into the high 20’s – likely around 26 or 27°C – while the dew point rises to around 21 or 22°C, making it feel very muggy.

Thursday’s overnight activity may be lingering in the morning, but it looks quite likely that things will become unstable late in the morning or early in the afternoon again, bringing more shower and thunderstorm activity. It’s still a little early to make very specific predictions, but if things pan out the way it looks now, there would be a very slight chance of severe thunderstorms in the Red River Valley with the main threats being torrential rain causing flash flooding[3] and large hail. We’ll be refining our convective outlook closer to the event since small changes between now and then – particularly with the night-time storms – can dramatically alter the forecast.

Friday night will be cloudier than not with an overnight low of 17°C. It looks fairly likely that a line of thunderstorms will develop through North Dakota along a weak cold front and track northeastwards through the overnight period. At this point it looks like that system will continue to bring a risk of thunderstorms to the Red River Valley through much of the night, but the best support for severe weather looks to remain in North Dakota/Minnesota.

Unsettled Weekend

The unsettled weather will continue through the weekend as yet another upper low begins building into the Prairies (the third in as many weeks). Saturday will likely see showers and thundershowers to the east and north of the Red River Valley to start the day. Much of the day may end up being fairly pleasant, so if that materializes get out and enjoy it!

A shortwave is forecast to move across the province on Saturday night, likely bringing another outbreak of thunderstorm activity. Severe weather may be possible.

Sunday looks to be a nice day, with the sun likely finally making an appearance and a high near the mid-20’s. The humid air should be off into Ontario by Sunday, so it will likely be quite a comfortable afternoon here in the Red River Valley.


  1. Unless a little more sun develops, then we may see 21 or even 22°C before showers take over.  ↩
  2. Dew point is a measure of how much water is in the air. Compared to relative humidity, it’s a more consistent representation of how humid it is.  ↩
  3. Which wouldn’t be particularly difficult, given the high water levels already in place.  ↩

More Unsettled Weather

Although nothing as notable as this past weekend’s rain event is in store, unsettled weather returns for the second half of the week.

Another sizeable low pressure system is making it’s wet presence felt, but this time the hardest hit area will be Southern Alberta where some portions in the foothills may receive as much as 200mm of rain this week. This system will slowly lumber eastwards through the next few days, slowly weakening as it does so but still producing thunderstorms and showers as it goes.

Wednesday: Severe Thunderstorm Risk for Extreme SW Manitoba

Wednesday
25°C / 13°C
More cloud than sun. Warm & breezy.

Winnipeg will see fairly pleasant weather today with mixed skies, likely leaning towards more cloud than sun, and a high near 25°C with a fairly stiff easterly wind at 30-40km/h thanks to a surface trough building southeastwards through North Dakota.

The main upper low, the heart of this large disturbance, will gradually edge eastwards through the day and will trigger thunderstorms, with some severe storms possible, through portions of southern Saskatchewan and southwestern Manitoba. Shower activity will start off the day in much of Southern Saskatchewan, but the southeast portion of the province will likely see things destabilize enough through the day that thunderstorms are likely by mid-to-late afternoon. The storm activity is most likely to initiate through western North Dakota and then build north/northwestward along the surface trough into SE Saskatchewan and into extreme SW Manitoba through the early evening.

There is an organized threat of severe weather with these storms; we’ve gone with a slight risk due to almost every severe weather parameter looking fairly good except lacking in some subtle way. The main threats will be strong winds and large hail, especially out of any storms that develop early and are sustained as discrete supercells. If the storms develop into a cohesive line, the severe threat will be diminished, although non-zero. There will be a very slight chance for tornadoes thanks to excellent low-level shear, low cloud bases, and a vorticity rich environment being advected eastwards by the upper-level low.

Today will bring a slight risk of severe thunderstorms into SE Saskatchewan and SW Manitoba.
Today will bring a slight risk of severe thunderstorms into SE Saskatchewan and SW Manitoba.

The severe storm threat will push eastwards into the Virden & Melita regions of Manitoba in the early evening with the main threats being strong winds and large hail. It does look like the tornado threat should be restricted to the Saskatchewan side of the border. Southwest Manitoba is in for quite a soaking overnight as the storms expand into an area of convectively driven rain; around 15-20mm is likely for most areas south of the Trans-Canada Highway and west of the Red River Valley (RRV), with as much as 40-50mm possible in areas that see thunderstorm activity as well.

As the area of showers pushes eastwards, it will gradually weaken into an area of showers with possible embedded thundershowers. It looks to reach Winnipeg by Thursday morning.

Thursday: Back to Wet Weather

Thursday
23°C / 14°C
Periods of rain. Around 10mm.

Thursday will be a cloudy day with a high near 23°C. Shower activity will be in the region in the morning and lift off to the northwest, however while that happens a new batch of rain will be develop to our south and lift northwards through the RRV. Around 10mm seems most likely through the day across most of the region, although if heavier shower activity ends up developing we may see closer to 15mm here in Winnipeg.

The shower activity will taper off on Thursday evening as it all lifts northwestwards into the Interlake and Parkland regions of the province. Winnipeg will see some clear breaks and a low near 14°C.

Friday: Cold Low Showers

Friday
23°C / 14°C
Mixed skies; showers or thundershowers developing midday.

Friday will see us underneath the upper-level low which essentially means that there will be a bunch of cold air high up in the atmosphere. With mixed skies, we’ll see temperatures increase towards our high of 23°C fairly quickly through the morning. By mid-day, we’ll likely have hit our high temperature and the atmosphere will become quite unstable. Expect widespread shower and thundershower activity through the Red River Vally. Rainfall amounts will be highly variable and dependant on how many showers any one spot sees and how fast things move along.

Overnight, the shower activity will consolidate to right around the upper low on Friday night as it drifts through our region and into Minnesota. The temperature in Winnipeg will drop to around 14°C.

Fairly Normal Start to the Week

This week will start out with fairly normal conditions for early June with a chance for rain, and moderate temperatures.

Monday will be a nice day in southern Manitoba
Monday will be a nice day in southern Manitoba

Monday

Monday
22°C / 13°C
Mainly sunny

Today may start out with a bit of rain in the morning as a piece of upper-level energy swings through but skies should quickly clear, making for a pleasant day. Any rain that does fall in the morning will be light, so it won’t be a big deal. By the afternoon we should see mainly sunny skies with temperatures in the low twenties and light winds.

Tuesday

Tuesday
23°C / 10°C
Chance of showers or thundershowers

Tuesday will see the chance for showers and thundershowers in the Red River Valley and south-eastern Manitoba ahead of an approaching trough. Any thundershowers that develop will present the risk of small hail and gusty winds. For those areas that miss out on the showers and thundershowers, it will be a nice day with temperatures in the low twenties and a breezy south-west wind.

Wednesday

Wednesday
19°C / 5°C
Mix of sun and cloud

A cold front will blow through southern Manitoba early Wednesday morning, setting us up for a slightly cooler day. Highs on Wednesday will be in the upper teens in most areas (perhaps a few readings in the low twenties), with skies being a mix of sun and cloud by the afternoon. The wind will be breezy and from the north.

Long Range

The long range forecast suggests we’ll continue to see normalish weather for the foreseeable future. That means high temperatures in the low to mid twenties and the frequent chance for rain or thunderstorms (albeit generally of the non-severe variety).

Sunshine Gives Way to Unsettled Weather

The beautiful summer weather will stick around for one more day before a large upper trough pushing across the Prairies spreads showers and generally unsettled weather into Southern Manitoba.

Forecast precipitation for Wednesday night from the RDPS.
Forecast precipitation for Wednesday night from the RDPS.

Today will be an almost ideal summer day across much of the Red River Valley. Sunny skies will gradually see increasing cloudiness through the afternoon hours, however before things cloud up temperatures will climb all the way up to around 27 or 28°C while light winds begin picking up in the afternoon to 20-30km/h.

Wednesday
27°C / 14°C
Increasing cloudiness in the afternoon.

The story will be a little different over southwest Manitoba today, where an incoming surface trough will combine with warm weather and moderate instability to produce mid-to-late afternoon thunderstorms. Around 1250J/kg of CAPE will combine with 25kt of bulk shear and a 25-30kt LLJ to support upscale growth from a few isolated thunderstorms to an eastward moving line by the evening. This line will weaken fairly quickly as it moves into the Red River Valley thanks to the loss of daytime heating and the storms moving away from their main support.

The overall threat of severe weather in southwest Manitoba is marginal. The main risks will be large hail, but that seems like a fairly off chance at best. A rogue wind gust can’t be ruled out either, but again, I don’t have particularly high expectations for severe weather. Were I the SPC, it would be a “See Text” sort of day.

This line will bring a chance of showers or thunderstorms to Winnipeg and the Red River Vally through the overnight hours. No severe weather is expected. Temperatures will drop down to around 15°C or so.

Thursday & Friday

Thursday
25°C / 10°C
Cloudy periods; slight chance of showers.
Friday
21°C / 8°C
A mix of sun and cloud.

Tomorrow will bring cloudy periods with a slight chance of showers through the day. The precipitation risk will increase towards evening as a second impulse digs the upper trough into Manitoba, leaving us with a chance of showers on Thursday night.

Cooler air will also start filtering in. Thursday’s high of 25°C will be replaced by cooler weather for the remainder of the week and weekend. The temperature will drop to around 10°C on Thursday night.

Things should push off to the east on Friday morning leaving behind some sunny skies, but skies look to become mixed midday. There may be a chance of seeing some rain on Friday afternoon, but guidance is very mixed right now as to whether or not a band of rain will push northeastwards out of North Dakota. At this point it seems more likely that things will stay dry than not. We’ll see highs across the Red River Valley top out around the 21°C mark. The overnight low on Friday night will drop into the high single digits.

The Weekend

The weekend across the Red River Valley is looking fairly nice, albeit a little cool. Saturday will see afternoon cloudiness bring a slight chance of late-day showers. Sunday looks fairly sunny, although cloud will likely increase in the evening ahead of another system forecast to push through the region on Monday. Highs will sit near the 20°C mark with overnight lows in the mid-to-high single digits.