Summer Returns to Southern Manitoba…For a Short While

Beautiful weather is on tap for Southern Manitoba with plenty of sunshine the next couple days and positively summer-like temperatures. Things will return back to normal on Friday, after a cold front sweeps across the province on Thursday night.

500mb Winds/Height for Wednesday Evening

500mb Winds & Heights from the GEMGLB, valid for 00Z Thursday 10 May. The upper ridge has been highlighted over Manitoba.

A deep southerly flow has moved into Southern Manitoba underneath an upper ridge sliding east over the Prairies, pushing warmth from the Central Plains of the United States into our area. Temperatures will climb to around 20°C today with winds increasing to 20-30km/h out of the south by the afternoon. Temperatures will only drop to around 10-12°C tonight as the southerly winds keep our temperatures up in this warmer air mass.

Tomorrow the real heat moves in, and we’ll see temperatures soar in the Red River Valley, with daytime highs between 24 – 27°C. We’ll see a bit more cloud, though, and dewpoints in the low teens will make it feel closer to 30°C.

Day 2 Thunderstorm Outlook valid 21Z May 10 to 12Z May 11

Day 2 thunderstorm outlook, valid from 21Z May 10 (Thursday afternoon) to 12Z May 11 (Friday morning). No severe thunderstorms are expected.

By tomorrow evening, a cold front sweeping across the province will move into the Red River Valley. With the extra moisture in the air from the higher dewpoints, CAPE values will be enhanced slightly, and we’ll be looking at 500-750J/kg of CAPE as the front pushes into the RRV. A band of showers and thunderstorms will fire along the cold front on Thursday afternoon over SW Manitoba and continue eastwards through the evening, crossing the RRV through the evening and pushing through the Whiteshell overnight.

Seasonal conditions are expected to return for Friday into the weekend.

The Upcoming Week

Sunshine and warm temperatures are the name of the game this week.

There’s not much to say for this week other than enjoy the nice weather.  A broad upper ridge will dominate the weather over the southern Prairies through most of the week.


12Z GEM-REG 500mb Heights & Speed valid 12Z Wednesday Oct 6.

A broad upper ridge sitting over the southern Prairies is bringing temperatures into the low to mid 20’s over Southern Saskatchewan and temperatures near 20 for Southern Manitoba.  This upper ridge will give way to a weak upper trough that will move across the Prairies Tuesday and Wednesday, however any rain associated with it will stay well north of the RRV and not effect our temperatures too much with them being limited only to the high teens.  After the trough moves by, then the upper ridge begins to build back and temperatures should head back into the low 20’s for the week’s end.

A warm and dry outlook is sure to be welcome news for farmers who have been battling waterlogged fields through much of the summer.

Mostly Sunny

Models indicate that there is a chance of showers late overnight and into tomorrow morning, and then we should return back to mostly sunny skies before cooler air pushes in for the weekend.


The GEM-REG model is currently the most aggressive in pushing rain through southern Manitoba tomorrow morning, as shown above in the 12H precipitation accumulation map valid 12Z Wednesday morning.

Sunny skies this evening should cloud up overnight as a cold front passes through southern Manitoba.  Most models lean towards just a slight chance of showers for the RRV, with a majority of the precipitation occurring in Northwestern Ontario.  The GEM-REG model, however, fires up a fair line of showers along the front as it passes through overnight, giving up to 5mm of rain to the RRV.  This solution currently looks to be an outlier, however so far this cold front has had a good history of precipitation along it.

Either way, it’s fairly certain that any accumulations that do develop should stick to the 5mm range, and will certainly be less than 10mm.   After the front passes through, we should see another mostly sunny day with a few clouds scattered around.

By Friday, as an upper ridge builds in the western Prairies, we should see a brisk northerly flow develop as a cold front slumps down through the province.  Expect cloudier skies than the forecast currently suggests in the afternoon.  The good news is that despite the chill in the air, precipitation is looking like it should stay north of Winnipeg.  Saturday looks to be a chilly day with 850 temperatures struggling to get above 0 for most of the RRV, and then we begin to transition back to warmer weather for the beginning of next week as the upper ridge moves east.