Warm, Humid, and Unsettled Weekend Ahead

Southern Manitoba will see humid conditions develop this weekend as a warm and unsettled pattern develops over the region.

RDPS 2m Dew Point Temperature Forecast valid 21Z Saturday June 15, 2024
Humid conditions will develop across southern Manitoba on Saturday.

To end the work week, an area of high pressure will gradually shift east out of the province through the day. This will bring a warm and settled day to the region with a high in the 25 to 30 °C range and partly cloudy skies. Southerly winds will begin to pick up later in the day and mark the beginning of the weather pattern that will persist through the weekend.

An upper trough will dig southwards over western North America through the weekend; this will support a prolonged southerly flow at the surface while disturbances eject northeast across the region over the next few days.

Humid Weather Arrives This Weekend

The southerly winds at the surface will draw heat and humidity northwards through the weekend. Daytime highs won’t be excessive through the weekend, likely in the mid-20s, but the region will likely see its first surge of humid conditions.

The humidity will be comfortable today with dew points in the low teens, but more humid conditions will quickly develop on Saturday. Dew point values will climb into the mid- to upper teens on Saturday, then hover in the 16 to 20 °C range overnight Saturday, then increase towards 20 °C ahead of a cold front on Sunday. As the cold front sweeps through on Sunday afternoon, drier air will sweep into the region and bring relief.

The humidity will keep temperatures warm on Saturday night with overnight lows in the 18 to 22 °C range across many parts of southern Manitoba.

Stormy Conditions Possible

Weather-wise, there will be several chances for stormy weather through the weekend. The first disturbance will be a weak area of low pressure that pushes into southern Manitoba tonight. Scattered showers and thunderstorms will be possible through the second half of the night into Saturday morning.

The activity will taper off on Saturday afternoon, then another disturbance will bring another chance of showers and thunderstorms to the region on Saturday evening and overnight. Sunday will be more settled, but there will be a low chance of showers or thunderstorms with the cold front as it sweeps east.

Long Range Outlook

Next week will start unsettled as the deep upper trough remains over western North America. Waves of rain and thunderstorms will be possible across southern Manitoba on Monday and Tuesday, then more settled conditions will move in for the middle of the week.

Today’s seasonal daytime high in Winnipeg is 23 °C while the seasonal overnight low is 11 °C.

Heat Builds in for the Weekend

An upper ridge building into the eastern Prairies will bring hot conditions to southern Manitoba this weekend.

RDPS 2m Temperature Forecast valid 21Z Sunday July 2, 2023RDPS 2m Dew Point Temperature Forecast valid 21Z Sunday July 2, 2023
Sunday will bring the warmest weather of the next few days as hot temperatures and high humidity build into the region.

Seasonably warm conditions will build into southern Manitoba over the next few days with daytime highs climbing towards the 30 °C mark. In Winnipeg, today will bring mainly sunny skies that give way to some cloud in the afternoon while a ridge of high pressure brings sunny skies for Saturday.

Temperatures both days will climb into the upper 20s. Humidity levels will be comfortable in the mid- teens both days. For those heading out to enjoy Canada Day ???????? on Saturday, it will be a beautiful day to spend time outdoors!

On Sunday, the heat will really arrive as temperatures climb into the low 30s with increasing humidity. By the late afternoon, dew point values could reach as high as 20 °C, which would make it feel more like the upper 30s.

On Sunday afternoon, a warm-sector trough — typically an area of lower pressure near the middle of a large area of warmer air — will begin pushing across southern Manitoba. This feature will be an area of concern for severe thunderstorm development later on Sunday.

The thunderstorm potential will be significant on Sunday thanks to ample heat and humidity at the surface and relatively cool temperatures aloft. MLCAPE values could exceed 2,000 J/kg in an environment with 20 to 30 knots of 0–6 km bulk shear. Veering wind profiles would support supercell structures, but moderate westerly forcing along the line would likely support upscale growth into the evening hours. Capping will be marginal — 700 mb temperatures are forecast to be around 9 °C — so there is uncertainty with where the southern end of the line would develop. Wind profiles aren’t overly backed at the surface, so this setup wouldn’t likely produce a widespread tornado threat. If a thunderstorm was able to tap into all the available energy, though, an isolated tornado threat could develop. More likely, these thunderstorms would be capable of severe hail and torrential rainfall.

The details of this could change between now and Sunday, but at this point it looks like Sunday will be the hottest day of the next few and bring an organized severe weather risk to the region for late in the day.

Long Range Outlook

A weak cold front will push through Sunday night easing the humidity across the region.

Through the start of next week, temperatures should sit closer to seasonal values with variable cloudiness as cooler air moves in under a slow-moving upper trough that moves into the region. Some showers could be possible, but right now it looks like the start of the week will be mostly dry for Winnipeg.

Today’s seasonal daytime high in Winnipeg is 25 °C while the seasonal overnight low is 13 °C.

Severe Thunderstorm Threat Followed By More Unsettled Weather

Hot and humid weather over southern Manitoba will lead to a thunderstorm outbreak on Tuesday afternoon. A cold front will slowly push across the region on Wednesday, bringing more showers with a risk of thunderstorms again, though severe weather is less likely. One last blast of unsettled weather will develop Thursday evening in North Dakota and spread into Manitoba overnight. By Friday, Winnipeg will see some more settled conditions.

RDPS 2m Temperature Forecast valid 21Z Tuesday June 20, 2023
It will be another hot day over the Red River Valley with highs in the 30s with dew points climbing over 20 °C.

There is a notable severe thunderstorm threat today in southern Manitoba as a hot and humid air mass continues building into the region. The main drivers of the weather today will be a warm sector trough that will arc from north-central North Dakota into the Interlake this afternoon and a cold front that is gradually shifting eastwards from the Manitoba/Saskatchewan border.

Along and east of the trough — which includes the Red River Valley — very hot and humid conditions will develop today. Daytime highs will climb into the low to mid-30s with dew points climbing up to around 20 °C. This will produce widespread humid values in the upper 30s or low 40s across much of south-central and southeast Manitoba. As this air mass cooks, it will bump up against the warm sector trough as it slowly shifts eastwards through the day.

By mid-afternoon, very significant amounts of energy for thunderstorm development will have built up in southern Manitoba. A quick summary of the afternoon’s convective parameter forecasts: MLCAPE values in the 2,000–3,000 J/kg range, bulk shear values of 25–45 knots, shear vectors aligned roughly along the convergence boundary, and STP values ≥ 1.

NSSL-WRF Forecast MLCAPE valid 21Z Tuesday June 20th, 20233km NAM Simulated Reflectivity valid 02Z Wednesday June 21, 2023
The NSSL-WRF model (left) shows clearly the axis of significant instability that develops on Tuesday afternoon. By 7PM CDT, thunderstorms will begin to develop and quickly grow into a complex of [potentially severe] thunderstorms within a couple hours (right).

The end result of all the parameters is this: thunderstorms will redevelop this afternoon and there will be numerous severe thunderstorms. Primary threats today will be very large, damaging hail and torrential rain. With so much energy to work with, it’s also likely that some thunderstorms will be able to produce damaging wind gusts. An isolated tornado or two is possible today, particularly early in the storm development later today.

Be sure to be aware of any severe weather watches or warnings issued by the Meteorological Service of Canada through the day today.

The thunderstorm activity will continue into the night, growing upscale along the trough and slowly shifting eastwards. Activity will refocus further south overnight where another disturbance riding northeastwards along the cold front, spreading more showers with the risk of thunderstorms into southern Manitoba by Wednesday morning. With the cold front further east, Winnipeg will see cloudier conditions through the day but temperatures could still be quite warm with highs in the upper 20s. Thunderstorm activity on Wednesday will be weaker overall than today, with a much lower risk of any severe-level activity.

More rain and thunderstorms is possible overnight Wednesday into Thursday as another disturbance rolls into the province along the slow-moving frontal boundary. It will support an area of nocturnal convection that will push into southern Manitoba, bringing what could be another widespread area of precipitation. There will be much less instability by this point, so little to no severe weather is likely with this final round of showers. This system will also bring cloudy skies to the region for much of Thursday with highs finally dipping back down into the mid-20s. The humidity stuck in the region will also finally begin to ease as the cold front slowly shunts southeastwards.

Long Range Outlook

More unsettled weather is likely this weekend as an upper low treks northeastwards out of the American Rockies, bringing a broad area of rain into southern Manitoba. There’s still some uncertainty associated with this system, but at this point it looks like a widespread 25 to 50 mm could be possible across many parts of southern Manitoba through a combination of rain and embedded thunderstorm activity. This system will clear out of the region to start next week, followed by another chance of showers on Monday evening as a cold front slumps into the region.

All in all quite an unsettled week ahead of us with numerous chances for showers and thunderstorms across the region. Particularly today, be sure to keep aware of the day’s thunderstorm development given the notable risk of severe weather.

Today’s seasonal daytime high in Winnipeg is 24 °C while the seasonal overnight low is 11 °C.

Hot and Unsettled Weather Continues

Hot and muggy weather will stick around in Winnipeg for a few more days along with more chances for thunderstorms. Some relief is on the way for the end of the week, though, with more seasonal conditions arriving on Friday.

A hot and humid air mass will remain in place over southern Manitoba on Tuesday.

An upper high entrenched over the eastern Prairies means little change is on the way for Winnipeg over the next few days. That said, there is a change on the way. A developing low pressure system over the southern Arctic is beginning to push cooler air into the northern Prairies. As it matures in the coming days, that cooler air will continue to slump southwards through the Prairies. By Friday, this cold front will sweep through southern Manitoba, clearing out the humidity and lowering temperatures back towards more seasonal values.

Before we get to that, though, there will be a few more days of hot and unsettled conditions in the Winnipeg area. The daytime high will reach the low 30s again today, then ease into the upper 20s for the next couple days. That humid air mass will keep overnight lows mild with lows in the 18 to 20 °C range.

Each of the next few days will also continue to bring a risk of thunderstorms across the region. Here in the Red River Valley, scattered thunderstorms are possible today, but not likely until closer to the evening. Much of the activity will stay west of the region on Wednesday, but an isolated thunderstorm is possible. On Thursday, a chance of thunderstorms will develop across the region later in the day as a cold front pushes through.

With the heat and humidity in the region, there will be a risk of severe thunderstorms over the region. That being said, most will likely be non-severe. Any that manage to organize to severe limits will mainly pose a torrential rain and hail threat.

Long Range Outlook

A break from the heat and humidity will stick around for the weekend, a welcome relief for many. Daytime highs will vary from the low to mid-20s this weekend, feeling very comfortable thanks to lower humidity levels. That drier air mass will also allow overnight lows to cool off into the low to mid-teens.

Warmer weather is expected to return next week with daytime highs climbing back into the 30s.

Today’s seasonal daytime high in Winnipeg is 23 °C while the seasonal overnight low is 9 °C.