Fall Arrives Early

Distinctly fall-like weather will dominate over Southern Manitoba through the rest of the work week as a (unfairly) cold low slumps southwards into Central Manitoba, spreading cool Arctic air southwards across the Red River Valley and into the northern Plains of the United States.

A cold low slumping southwards into Central Manitoba will bring cooler, distinctly fall-like weather to Southern Manitoba. Image depicts 700mb temperatures for midday today.

A cold low slumping southwards into Central Manitoba will bring cooler, distinctly fall-like weather to Southern Manitoba. Image depicts 700mb temperatures for midday today.

Today & Tonight

Wednesday

18°C / 8°C
Mainly cloudy with a chance of showers.

We’ll see mainly cloudy skies today as the upper low continues it’s southwards trek pushing cool, unstable air into the Red River Valley. There may be some drizzle or a few showers to the in the lee of Lake Manitoba and the south basin of Lake Winnipeg this morning, although there may be enough wind shear to prevent any lake-effect precipitation from forming in this cool air mass. Temperatures will climb to only around 18°C today with some scattered showers developing through the day in most areas of the Red River Valley. The clouds and showers will move out in the evening leaving us with clear skies and light winds as we drop down to a temperature of around 8°C.

Thursday & Friday

Thursday

20°C / 11°C
Mainly cloudy with a chance of showers.
Friday

22°C / 9°C
Cloudy with a chance of showers in the morning then clearing.

Thursday will start off nice and sunny but quite cool. Scattered clouds will develop midday before a more organized area of cloud begins work it’s way into the city from the north in the afternoon. The afternoon cloud will limit our daytime high to only around 20°C. By late afternoon or early evening we’ll see a chance of showers move into the Red River Valley as another batch of moisture wraps around the back-side of the upper low and down through the Interlake. The cloud cover will help keep our overnight low a little warmer – close to 11°C – instead of the cooler temperatures of Wednesday night.

Early Friday morning we’ll probably see mostly cloudy skies with a chance of showers. The cloud cover will push out in the mid-to-late morning and we’ll be left with sunny skies and a high near 22°C. Friday night will be cloudy with a low of around 9°C.

Hope For the Weekend?

While some long-range models are forecasting temperatures in the mid–20’s, at this point it doesn’t look like we’ll see a warm-up that quickly. While the cold air definitely begins to push off to the east through the weekend, no particularly warm air is pushing in to replace it. We’ll see gradual warming thanks to the sunny skies, but at the moment a more conservative forecast of temperatures climbing towards the mid–20’s – instead of rocketing past it – is probably a safer bet. At this point it does look like it will be nice and sunny through the weekend, though, so all in all it will be quite pleasant.

Nice Holiday Monday, but Then it Gets Ugly

The last day of the long weekend will be quite nice, but then conditions will turn ugly for Tuesday as a strong cold front pushes through.

Monday will be a Generally Pleasant Day in Southern Manitoba

Monday

Monday

Mix of Sun and Cloud. Chance of Showers.
25°C / 14°C

Today will be fairly nice in Southern Manitoba. Afternoon temperatures will be in the mid twenties under a mix of sun and cloud. The atmosphere will be a bit unstable later in the day, meaning that some isolated showers or thunderstorms may develop. These showers and storms are most likely to occur along and north of the Trans-Canada, though some areas south of the highway will still stand a slight chance of seeing an isolated cell move through. Wind speeds will be light, so overall it will be a quite a nice day in those areas that don’t see any showers or storms move through.

Tuesday

Tuesay

Rain early, then Decreasing Cloudiness
18°C / 5°C

The weather will be in transition on Tuesday as a strong cold front blows through early in the morning, setting up unseasonably cool weather for much of the week. There will likely be some showers, or perhaps even thundershowers, associated with this front as it passes through. However, amounts don’t look to be particularly high. In total, amounts will probably range from about 5 to 15mm, with locally higher amounts. Once the rain clears the region on Tuesday morning, temperatures won’t recover very much. Highs on Tuesday will only be in the mid to upper teens with a stiff northerly wind. Obviously Tuesday will be an unpleasant day, certainly not what we’d hope for in early August.

Wednesday

Wednesday

Increasing Cloudiness. Chance of Showers.
19°C / 9°C

Wednesday will be another cool day in Southern Manitoba from start to finish. Early morning temperatures will be in the mid single digits, with a recovery to the upper teens or perhaps twenty degrees by afternoon. Unfortunately, the atmosphere will quickly destabilize with daytime heating, prompting numerous showers to develop by afternoon. By this point you can probably recognize that this week isn’t going to be very nice.

Long Range

Medium range weather models suggest that the remainder of the work week will stay cool and showery. In the longer range models suggest we may begin to see temperatures trend back towards normal by next weekend, but that is still a bit far away to get overly excited about.

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.