Temperatures will hover at seasonal to slightly above-seasonal values until a low pressure system moves through on Friday and kicks off a major pattern change that will bring significantly cooler weather to the region.

Winnipeg has a couple nice days ahead as a ridge of high pressure keeps skies fairly clear and temperatures continue slightly above normal with highs in the mid-to-upper 20’s. Winds will be light today, but pick up out of the south on Thursday to around 30-40 km/h as a trough of low pressure moves into Saskatchewan. Tonight will see a low near 12°C, but on Thursday night a combination of cloud cover moving in, continuing windy conditions, and increasing dew points will keep lows much higher at around 17°C.

Friday’s main focus will be a low pressure system tracking eastwards through the province. At this point, it appears that it will likely develop an area of thunderstorms over Saskatchewan on Thursday afternoon, then track into Manitoba overnight. The exact placement and timing of the system has a lot of uncertainty at the moment simply due to the unpredictable nature of convection in the long-range, but in general it appears that Winnipeg will see a chance of showers or thunderstorms from fairly early in the morning until mid-afternoon or so, followed by winds shifting out of the northwest and clearing skies. It will also be a bit of a muggy day with dew points climbing into the upper teens. We’ll be able to paint a much clearer picture of this system in our next forecast post.

Long Range

The biggest weather story for the region will be the transition that takes place behind Friday’s system. Once it moves through, the upper-level ridge over western Canada is expected to amplify quite significantly, bringing another heat wave to B.C. and portions of Alberta. The flip-side to that will be the digging of a long-wave trough over central Canada, which will bring a northwesterly flow to our region and allow much cooler air to spill southwards out of the Arctic.

This could bring daytime highs as cool as 15-16°C by early next week, around 5°C below normal. This pattern would also likely bring partly cloudy to mixed skies and occasional chances for showers. It appears conditions will begin returning towards normal late next week and through the weekend.

Winnipeg’s seasonal daytime high is currently 22°C while the seasonal overnight low is 9C.

The weekend will bring a fair amount of warmth to Winnipeg and the Red River Valley, but alongside it will come some chances for isolated to scattered showers or thunderstorms.

Today will begin with an upper-level disturbance sliding out of southwestern Manitoba into North Dakota. As it moves eastwards, it will spread some cloud into the Red River Valley along with along with a low chance of isolated to scattered showers or thunderstorms further south in the valley towards the Morden-Winkler-Altona area. The partly cloudy to mixed skies will clear out through the morning and early afternoon, leaving sunny skies as temperatures climb to a high near 28°C. Winds will be relatively light out of the west to northwest at 10-20 km/h. Expect clear skies tonight with calm winds as temperatures head to a low near 15°C, kept relatively mild by a warm front that moves through in the evening and overnight hours.

Saturday will be a scorcher over southern Manitoba as we move into the warm sector of a low pressure system tracking across the northern Prairies. Temperatures will climb towards a high near 32°C under mainly sunny skies with winds becoming fairly breezy out of the south at close to 30 km/h for the afternoon. Fortunately, humidity shouldn’t be too much of an issue. Late in the afternoon, a cold front will begin pushing across southwestern Manitoba into the Red River Valley, and that will bring with it a risk of thunderstorms. At this point, it looks like there will be a slight chance of strong to marginally severe thunderstorms moving from west to east through the Red River Valley from around 6-7PM until midnight. Temperatures will then head to a low near 15°C again with gusty northwesterly winds behind the cold front tapering off overnight.

Sunday will bring cooler temperatures to the region as breezy westerlies at 20-30 km/h develop and highs reach a near-seasonal 25°C or so. Skies will partly cloudy and there may be an isolated shower or two passing through, but no particularly intense rain is expected. Expect mixed to cloudy skies on Sunday night as temperatures dip to a low near 14°C.

Long Range

Next week will start with mixed skies and near-seasonal temperatures and continue that way through much of the week, albeit with a bit more sunshine working in as the week progresses. It looks fairly dry at this point with no significant threats for rain on the horizon until next weekend. It appears that temperatures will creep towards the upper 20’s once again as the week progresses. Overall, it looks like it’ll be another warm and dry week.

Winnipeg’s seasonal daytime high is currently 25°C while the seasonal overnight low is 11°C.

A disturbance moving through Southern Manitoba today is bringing showers and thunderstorms across many areas this morning, and will be the focus for the redevelopment of more significant thunderstorm activity this afternoon. Once the disturbance leaves the region tonight, it’s nothing but beautiful weather ahead for Winnipeg & the Red River Valley.

A frontal wave collapsing southwards through the region is bringing scattered showers and thunderstorms to the region this morning, and will continue to for much of the day. The focus for most of the thunderstorm activity will be a shortwave spinning up along the international border. This feature will support an area of slow-moving thunderstorms this afternoon; these storms will potentially be capable of producing significant rainfall totals due to their slow speed.¹ Where exactly these thunderstorms develop will depend exactly on the track o the shortwave; at this point though it looks like the most likely area is south of the Trans-Canada Highway between Pilot Mound and Emerson.

Other than the rain, today will see temperatures climbing to a below-seasonal high near 20°C with winds out of the northeast at 20 gusting to 40 km/h.

The showers and thunderstorms will head out of the province to the southeast later this afternoon into the evening. Skies will clear as temperatures head to a low near 10°C with light winds.

Thursday and Friday will bring pleasant weather back to the region with plenty of sunshine, highs near 25 or 26°C, and lighter winds. Expect a low near 11°C on Thursday night and near 14°C on Friday night.

Long Range

Looking further ahead, the general trend will be for the upper-ridge over B.C. to gradually work its way eastwards, bringing mild and dry weather to the region. Expect to see seasonal to above-seasonal temperature build in through the weekend with the potential for more humid weather to arrive next week. It also looks fairly dry precipitation-wise with little chance of rain until the latter half of next week.

So make it through today and there’s plenty more sunshine and summer warmth to enjoy ahead!

Winnipeg’s seasonal daytime high is currently 26°C while the seasonal overnight low is 12°C.

1. Anywhere from 25 – 75 mm seems possible with today’s thunderstorms. ↩