Rain Brushes Southern Manitoba

A powerful low pressure system drenching North Dakota and Minnesota will brush the southeastern portion of the province today. For the rest of us, fairly quiet weather will prevail with slightly below-normal temperatures.

Wednesday
17°C / 8°C
Mainly cloudy. Outside chance of some light showers.

Thursday
18°C / 6°C
Mainly sunny.

Friday
23°C / 13°C
Sunny, then increasing cloud late in the day.

The main weather story today will be the low pressure system working its way through North Dakota and Minnesota. Although this system will spread cloud through the entirety of the Red River Valley, rainfall will be constricted to the southeastern portion of the Red River Valley into SE Manitoba. At this point, it looks like the main area of rain will remain south and east of Steinbach. There’s a slight chance of showers backing into Winnipeg and the SW Red River Valley (Altona, Winkler), but if any precipitation managed to push that far north or west, it would remain very light.

Forecast rainfall amounts for the system clipping southeastern Manitoba through June 11th and 12th.
Forecast rainfall amounts for the system clipping southeastern Manitoba through June 11th and 12th.

Otherwise, it will be a mainly cloudy day with perhaps a few sunny breaks through the first half of the day. Winds will be a little breezy out of the north at 20-30km/h. Temperatures will top out around 17°C. Clouds will begin to push off to the east overnight, however the bulk of the RRV won’t see complete clearing until Thursday morning. Overnight lows will be near 8°C.

Cool But Pleasant End to the Week

Thursday and Friday both look to be quite nice, with temperatures some 5°C below normal returning to seasonal values. Thursday will see clearing skies as temperatures climb to 18°C. Winds will be light out of the north as a ridge of high pressure begins working its way eastwards into Manitoba. There may be a slight chance of some shower or thundershower activity over western Manitoba, but here in the Red River Valley things look sunny and dry. The overnight low on Thursday will generally sit around 6°C; this will likely be the coolest night for the next while.

Friday will be another mainly sunny day with warmer weather returning as the ridge of high pressure shunts off to the east and a southerly flow redevelops over the province. Under mainly sunny skies the temperatures will climb to near 23°C. Cloud will move into the Red River Valley late in the afternoon or the evening and the next system pushes into southwestern Manitoba. Temperatures will drop to around 13°C.

Unsettled Weekend

This weekend will be marked by unsettled weather as a major low pressure complex moves into Southern Manitoba and the Northern Plains of the United States. Rain, with the chance of thundershowers, will push into southwestern Manitoba on Saturday morning. There’s uncertainty as to what will happen after that, but at the time it appears that rain will likely slide eastwards along the international border through the day.

GDPS 24hr. precipitation amounts from Saturday evening to Sunday evening. The GDPS is forecasting 5-10mm of rain in the RRV for this period, with higher amounts west, south and east.
GDPS 24hr. precipitation amounts from Saturday evening to Sunday evening. The GDPS is forecasting 5-10mm of rain in the RRV for this period, with higher amounts west, south and east.

Afterwards, the general trend looks to be a shift northwards with the precipitation towards the northern Red River Valley, and then things push out late in the day on Sunday. Daytime highs on the weekend should rest in the low 20’s while overnight lows hover near the 11-12°C mark.

Warm Weather to Continue

Seasonal to above seasonal weather will continue this week, a nice change from the miserable first part of May.

There will likely be a chance of thunderstorms in southern Manitoba on Tuesday
There will likely be a chance of thunderstorms in southern Manitoba on Tuesday

Monday

Monday
24°C / 13°C
Mix of sun and cloud

Today will feature much calmer weather than what was experienced on the weekend. High temperatures will be in the low to mid twenties in southern Manitoba under a mix of sun and cloud. The wind will generally be light and from the north or east.

Tuesday

Tuesday
27°C / 15°C
Mix of sun and cloud with risk of a thunderstorm

The threat for thunderstorms will resume in southern Manitoba on Tuesday. At this point there is still a lot of uncertainty as to how the thunderstorm risk will evolve. At the high end, there could be numerous severe storms, and even a slight tornado risk. At the low end, storms would likely just produce small hail and gusty winds. It’s too early to say what the storm mode will be on Tuesday, but bear in mind that severe storms are a possibility. The chance of thunderstorms on Tuesday will make the temperature forecast a bit uncertain as well. If there are no storms, and therefore no additional cloud cover, then we’re looking at temperatures in the upper twenties. However, if there is additional cloud from thunderstorm activity, then highs will probably be in the mid twenties. More details on Tuesday’s potential for storms will no doubt be found in the comments below over the next couple days.

Wednesday

Wednesday
25°C / 16°C
Mix of sun and cloud with risk of a thunderstorm

Wednesday is another tricky forecast, as rain may or may not affect the forecast again. Some weather models bring an area of rain and thunderstorms through southern Manitoba in the morning, which would greatly impact the temperature forecast. Like Tuesday, it’s too early to say if this will happen, but it’s certainly a possibility. High temperatures in the mid twenties look most probable, but that outlook could change depending on what happens with the chance of rain.

Long Range

The long range forecast continues to look stormy through the end of the week. Most weather models suggest that there will be a risk of severe thunderstorms in southern Manitoba on Thursday and/or Friday. I feel like I’m saying this a lot, but there is still a lot of uncertainty in this part of the forecast. Models are still not correctly resolving the speed of this system, and until that happens it will be tough to say much about the thunderstorm potential with any certainty. Beyond this week, the weather will likely stay near, to slightly above seasonal values, a nice way to transition into June!

Another Week, Another Rainstorm

The final day of the Victoria Day long weekend will see rain over much of southern Manitoba. It seems that early-week rain is becoming a new tradition of sorts.

A low pressure system will bring rain to much of southern Manitoba on Victoria Day
A low pressure system will bring rain to much of southern Manitoba on Victoria Day

Monday

Monday
16°C / 9°C
Periods of rain.

A low pressure system moving out of the northern United States will bring moderate rain to most of southern Manitoba today. Accumulations of 5-15mm are expected in Winnipeg and the Red River Valley. Areas further west, in south-western Manitoba, can expected accumulations of 15-25mm. There’s a slight chance of a thunderstorm in areas near the international border, but they should amount to little more than a rumble or two and slightly heavier rainfall.

Tuesday

Tuesday
13°C / 10°C
Showers.

The low pressure system from Monday will remained stalled out over southern Manitoba on Tuesday. That means we’ll see showers continue through the day on Tuesday, but actual rainfall accumulations will generally be light.

Total rainfall expected from Sunday evening to the time everything tapers off on Tuesday evening.
Total rainfall expected from Sunday evening to the time everything tapers off on Tuesday evening.

Wednesday

Wednesday
16°C / 4°C
Mainly sunny.

The weather will finally begin to relent on Wednesday, as skies clear and temperatures climb into the mid or upper teens. There will be a breezy north wind on Wednesday, but it will be a nice day overall. Wednesday’s return to reasonable weather signals a major pattern change that is expected to bring much warmer conditions by the weekend.

Long Range

The long range forecast is finally looking hot for a change. Medium-range weather models suggest we could reach the upper twenties, or near thirty degrees by the weekend. There’s still some uncertainty in terms of how hot it will get, but it definitely looks like some above normal weather is finally on the way!

Moderating Trend Gives Way to Rainy Holiday

Temperatures will moderate to seasonal values by the end of the weekend, but the Victoria Day holiday may end up being quite wet.

Relief is in store for Southern Manitobans weary of the prolonged cold weather as milder air is finally set to return to the region. The intense upper-level cold trough over Ontario that has been bringing a strong northerly flow and cool weather to the region will finally begin to collapse, allowing milder air to work its way eastwards again. Temperatures will remain fairly mild while the weather takes a turn for the worse on Victoria Day as a low pressure system brings the potential for substantial rains across much of Southern Manitoba.

Friday
14°C / 0°C
Mainly sunny.

Saturday
18°C / 6°C
A few clouds.

Sunday
18°C / 8°C
Mixed skies.

Today and tomorrow will see daytime highs climbing towards the high teens with minimal in the way of cloud cover. Both days will also see light winds thanks to a ridge of high pressure situated over the province. We’ll likely see temperatures dip to the freezing mark tonight[1], but milder air will be in place for Saturday night making the overnight low around 5°C warmer.

Sunday will be a more unsettled day. Most places in Southern Manitoba will see cloudy periods with a very marginal chance of a shower. Winds will shift out of the south to 20-30km/h as a warm front lifts northwards through the day. Temperatures should climb to around 18°C and the temperature will drop to around 8°C on Sunday night.

Potentially Stormy Victoria Day Holiday

Monday
15°C / 10°C
Mainly cloudy; rain likely.

A powerful low pressure complex will develop over Saskatchewan on Monday which will bring wet weather to Southern Manitoba as a conveyor belt of warm, moist air sets up all the way from the Gulf of Mexico. We won’t see that warm, humid air at the surface, but thanks to a strong southerly flow aloft, strong isentropic ascent over the warm front will produce a very saturated, potentially unstable atmosphere over Southern Manitoba.

Rainfall forecast (in inches) from NOAA's WPC for Sunday evening through Tuesday evening. The WPC is forecasting as much as 25-30mm of rainfall for Southern Manitoba.
Rainfall forecast (in inches) from NOAA’s WPC for Sunday evening through Tuesday evening. The WPC is forecasting as much as 25-30mm of rainfall for Southern Manitoba.

What does this mean? We could see fairly heavy rainfall on Monday. There is still enough time for things to change substantially between now and then, but amounts anywhere from 5-25mm seem quite possible. The rainfall does seem quite convectively driven, and with a moderately strong 850mb jet there’s always the possibility the rainfall becomes attached to the left-exit region and ends up remaining to our south/southeast. We’ll be tracking this system through the weekend and have updates below when things begin to take shape.


  1. Hopefully for the last time until the fall.  ↩