Quiet, Mild Weekend Ahead

A very benign weather pattern will move over Southern Manitoba as a ridge of high pressure builds into Manitoba bringing increasingly sunny skies and temperatures slowly trying to climb towards seasonal.

Friday

21°C / 9°C
A mix of sun & cloud.
Saturday

24°C / 11°C
Mainly sunny.
Sunday

24°C / 11°C
Mainly sunny

We’ll see a mix of sun and cloud today as daytime heating is able to produce some shallow convection, but there won’t be enough instability remaining to produce any precipitation as subsidence moves in ahead of the approaching ridge of high pressure. Today will be our coolest day with temperatures only climbing into the low 20’s. Tonight will be quite cool with our temperature dropping just under 10°C by tomorrow morning.

Tomorrow we’ll be under the influence of the high and we’ll see mainly sunny skies as temperatures climb back towards more seasonal highs – which for this time is around 26°C – of around 24°C. Sunday will be nearly a carbon copy of Saturday with a high near 24°C and an overnight low of around 11°C.

Next Week

We’ll start next week with a fairly nice day on holiday Monday with highs in the mid–20’s under a mix of sun and cloud.

NAEFS 8-14 Temperature Anomaly Outlook produced at 12Z August 1, 2013

NAEFS 8–14 Temperature Anomaly Outlook produced at 12Z August 1, 2013. Areas in red indicate above-normal temperatures, while areas in blue indicate below-normal temperatures, expected for the week after next (8–14 days from now).

The rest of the week looks to be fairly steady temperature-wise, however some models are hinting at a system that may bring some showers or thunderstorms to the region mid-week. No significant warm-up is in sight as a persistent vortex continues to redevelop over northern Ontario and Hudson Bay, keeping a persistent northwesterly flow over the eastern Prairies.

Slightly Cool Weather Continues

A persistent low-pressure centre over Hudson Bay will continue to bring cool nights and mild, but not hot, summer days to Winnipeg as it blocks the jet stream from pushing northwards into the southern Prairies.

Wednesday

23°C / 13°C
Partly cloudy with a slight chance of late-day showers.
Thursday

22°C / 12°C
Partly cloudy with a tiny chance of late-day showers.
Friday

22°C / 10°C
Partly cloudy.

The next few days will see very little variation as cooler air ever so slowly slumps southwards into the Southern Prairies. We’ll see a chance of late-day showers in the Red River Valley today and tomorrow, however the chance is pretty minuscule and by no means will the showers be widespread. Temperatures will climb into the low 20’s for highs and start around 13°C for overnight lows and drop towards the 10°C mark by the end of the week. By friday the chance for showers drops off and we’ll likely just see a few clouds in the afternoon.

No Heat on the Horizon

Looking ahead to the long-range it doesn’t appear we’ll see any hot summer weather headed our way for the next 7–10 days. The low that’s keeping us cool is going to stick around for a couple days before backing up to the west, grabbing another batch of cool Arctic air and then diving southwards towards Southern Manitoba…at least, that’s how it looks now. It seems somewhat reasonable as most models have locked into a fairly consistent west-coast ridge and mid-continental toughing pattern for the next while.

Personally, I love the warm but not hot days and cool nights, although given our long-delayed spring, I’m not going to complain if nature can throw another blast of hot and humid weather our way again.

Sunny Weekend Ahead

Sunny weather will dominate the Red River Valley as a ridge of high pressure moves into Manitoba. Temperatures will be below-normal through the next 3 days as we remain entrenched in a cooler air mass originating from the north while the jet stream remains locked up in the United States.

Friday

20°C / 7°C
Mainly sunny.
Saturday

22°C / 11°C
Mainly sunny.
Sunday

24°C / 13°C
Mainly sunny.

Temperatures will slowly climb back towards the mid-20’s by the end of the weekend, while overnight lows will start at an extremely unseasonably cool 7 or 8°C and warm to around 13°C by Sunday night. Skies will be mainly sunny the next several days with no precipitation in sight.

A Chance to Dry Off

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:

City/Town Rainfall (mm)
Deerwood 101
Morden 89
Somerset 81
Winkler 77
Manitou 76
Sprague 73
Letellier 71
Killarney 69
Carman (Ag.) 68
Altona 67
Boissevain 62
Carman (EC) 58
Gretna 58
Deloraine 55
Emerson 55
Morris 54
St. Pierre 52
Kleefeld 46
Treherne 41
Pilot Mound 40


Winnipeg 18–24 (Official)
29–34 (Unofficial)
Portage la Prairie 18
Brandon 16

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.