We’ll see sunny skies through the rest of the week and a chance to dry off after as much as 100mm of rain fell over Southern Manitoba over the weekend. The heavy rain caused a few problems of the weekend, mainly constrained to rapidly rising streams and rivers (which rose as much as a meter) and significant overland flooding. Thornhill, MB was particularly hard hit with enhanced rainfall occurring from the upslope enhancement of the western Red River Valley escarpment under northeast winds. It has been reported that 200mm or greater fell in the region, but with such sharp contrast to how much fell in nearby Morden (89mm) and CoCoRaHS reports totalling 2–3” (~ 50–80mm), it has to be considered an extremely localized event. Nonetheless, areas very close to the western escarpment were hit very hard by this rainfall event.

All that to say it was a very wet weekend that was easily the biggest rainfall event of the year. Some notable rainfall totals:

It’s easy to see that the heaviest rainfalls fell in the SW Red River Valley, with lesser amounts east of the Red River and rapidly diminishing amounts near the Trans-Canada Highway. Fortunately, no rainfall is in the forecast for this coming week, which should provide the opportunity for things to dry off and a chance to get out there and cut your grass which, if it’s anything like mine, decided to grow about 4” over the past few days.

Wednesday

20°C / 3°C
Mainly sunny & breezy.

Thursday

17°C / 4°C
Mainly Sunny

Friday

19°C / 9°C
Mainly Sunny

We’ll see mainly sunny skies the next few days as a large surface ridge pushes through the province. High temperatures will be restricted into the mid-to-upper teens as cooler air aloft dominates along with a northeasterly wind that will keep cooler, dryer air feeding into southern Manitoba. Winds will still be a factor today as they increase to around 30–40km/h once we warm up a little bit. Winds will be a lesser issue on Thursday as the surface ridge lies right on top of us and the light winds slowly shift to southeasterly as we enter the return flow on the back-side of the ridge. For Friday, winds will likely pick up late in the day or overnight as the surface pressure gradient tightens up over southern Manitoba again as a low pressure system pushes into eastern Montana/the western Dakotas. Before then, though, the winds will likely be quite calm. Our high on Friday will push back towards the 20°C mark, but likely stop just short of it.

The return flow also looks to be tapping into a bit of moisture in the Central Plains which will begin increasing our dew points heading into the weekend. For us, it will just mean the assurance that we’ll stay much warmer at night (closer to 10°C than 5°C), but for further west in Eastern Saskatchewan it looks like the moistening air may provide fuel for the first organized thunderstorm events of the year.

The Weekend

The weekend looks to be fairly benign at this point over Southern Manitoba. It looks like the atmosphere is setting up into a weak blocking pattern once again with a large upper low spinning over the B.C. Interior and Alberta with upper ridging over the Eastern Prairies. There may be a few shortwaves that ride up the ridge, but at this point it looks like if any shower activity were to push into Southern Manitoba, it would be constrained close to the Saskatchewan border. At this point, I’m comfortable saying that we’ll probably see a mix of sun and cloud with highs in the low 20’s here in the RRV this weekend, with more showery, stormier weather confined mainly to our neighbours in Saskatchewan.