Winter’s On The Way

The (seasonally) gorgeous weather we’ve been having to start off November will be coming to an end this weekend as a pool of cold air that’s been dammed up north of 60° spills southwards behind a storm system that will push across the province on Friday. The result will be an abrupt transition from temperatures in the mid-single digits on the warm side of zero to highs well below the normal 2°C. In addition the cooler weather, Southern Manitoba will move into a busier weather pattern that will produce multiple threats for precipitation over the coming week, including what may be our first snowfall that “sticks.” After a quiet 5 weeks, it looks like the weather is set to get much busier in Winnipeg!

Wednesday
3°C / -1°C
Cloudy

Thursday
3°C / -2°C
Mainly cloudy

Friday
4°C / -1°C
Morning snow changing to periods of rain

Before things begin to get busier, Manitobans in the Red River Valley will get another couple days of above-normal temperatures to enjoy. Both today and tomorrow will bring mainly cloudy skies thanks to persistent stratus cloud that will struggle to clear out of the region. A few sunny breaks may show up, but generally cloudy skies will be the common theme. Temperatures will climb to around 3°C for the daytime high today.

Another batch of flurries is expected to move through the Interlake tonight.
Another batch of flurries is expected to move through the Interlake tonight.

Another round of flurry activity is expected tonight as a trough pushes through the region. The overnight low will drop

Thursday will bring a repeat performance for the high, but with a few more clear breaks likely on Thursday night, the low will drop a bit lower to around -2°C. No significant precipitation is expected either day.

Friday: The First Snow?

Friday will mark the start of our transition into a stormier, colder weather pattern. A low pressure system moving from southeastern Saskatchewan into North Dakota will spread an area of snow eastwards into southwest Manitoba on Thursday night, pushing eastwards into the Red River Valley on Friday morning. It looks likely that the precipitation will reach from the American border into the Southern Interlake[1], however the bigger challenge as this system pushes eastwards will be what type of precipitation will be falling out of the sky.

5-10mm of liquid-equivalent precipitation is expected on Friday; how much of that falls as snow remains to be seen.
5-10mm of liquid-equivalent precipitation is expected on Friday; how much of that falls as snow remains to be seen.

With a high of just +1°C, it will be a fine line between rain and snow, with a shallow above-freezing layer right at the surface working to try and melt snow as it moves into the lowest levels of the atmosphere. As the morning progresses, warmer air will push in aloft and help snow transition into rain. All in all, it doesn’t seem like a ton of snow will fall; perhaps 2-4cm, however with the switch-over to rain and temperatures climbing above zero, it’s unlikely that it really has much of a chance to accumulate or stick around.

With temperatures hovering near or just above 0°C through the morning, exact timing of rain and snow will remain somewhat uncertain until much closer to this system’s approach.

Temperatures will dip below zero on Friday night as they head to the overnight low of -1°C or -2°C. The freezing temperatures following the rain or snow we see could end up creating quite slippery road conditions, so if you need to travel on Saturday, now’s a great time to brush up on your winter driving skills!

Weekend Brings First Taste of Winter

Behind Friday’s system, significantly cooler air will begin working its way into the province. Temperatures will fall below zero to around -3°C or so for daytime highs and around -8°C[2] for overnight lows. Some lake-effect snow may be possible in the lee of the lakes on Saturday with the cool northwesterly winds moving over the still-open water.

Another low pressure system will move through on Sunday, bringing the first chance for a significant snow event to the Red River Valley. It’s still too far out to try and speculate just how bad it will be, but current model output is showing the potential for anywhere from 10-20cm of snow by Monday morning. It’s still a long ways out, though, and this system could easily end up to our north or south. Consider it added to our storm watch list.

So, with the arrival of winter fairly imminent, enjoy the last couple above-zero days!


  1. There’s a little disagreement with some models suggesting the precipitation remains mainly south of Winnipeg, but at this point it looks like a fairly safe bet that Winnipeg will be impacted by this system.  ↩
  2. …-ish.  ↩

Another Cold Snap in Southern Manitoba

Moderately miserable, categorically cold; the weather leading into this weekend will be fairly miserable as a large low pressure system moving through Ontario exerts its influence over southern Manitoba causing strong northwesterly winds as the coldest shot yet of Arctic air plunges southwards into the United States.

Friday
5°C / -1 to 2°C
Cloudy with showers. Flurries possible in the morning. Strong NW wind to 50km/h.

Saturday
7°C / 0–2°C
Clearing except cloudy in the lee of the lakes

Sunday
9°C / 3°C
Mixed skies with a slight chance of isolated showers or drizzle

Friday: A Miserable Fall Storm

The Red River Valley will be under the grip of a miserable fall storm lifting northwards through Northern Ontario today, driven by a massive push of cold Arctic air sweeping through Manitoba. We’ll see a very cold start to the morning with temperatures hovering around 2–3°C, strong northerly winds at 40–50km/h with gusts as high as 70–75km/h and a band of rain stretching north-south through the region. Embedded within the band will likely be some convection, significant since increased precipitation intensity could mean that in addition to the rain, we might see brief bursts of snow as well.

The precipitation should taper off by early afternoon, but we’ll still be left with a strong northerly wind and temperatures struggling to get to our high of 5°C. If the sun manages to poke out at all, we may eke out a 6°C for a high, but that looks quite unlikely.

The RDPS clearly shows Winnipeg nestled between two bands of lake-effect precipitation on Friday night.
The RDPS clearly shows Winnipeg nestled between two bands of lake-effect precipitation on Friday night.

Winds will begin to taper off tonight to around 20km/h. Combined with the cold air, the lake-effect machine will likely start up again, producing lake-effect showers or snow through the overnight period across regions in the lee of the lakes. At this point it looks like Winnipeg will remain safely between the two bands of lake-effect precipitation. The overnight low will be anywhere from –1 to 2°C, depending on exactly how much cloud remains in the area. Here in Winnipeg we should end up on the colder end of things under clearing skies.

A Chilly Weekend

It will be a chilly weekend in Winnipeg with temperatures on Saturday and Sunday both climbing only into the mid-to-upper single digits. Saturday should be a fairly nice day with mainly sunny skies in Winnipeg, but just to our west and east, lake-effect cloud (and likely precipitation) will be ruining a few people’s day. Temperatures will dip to the 0 to 2°C range Saturday night with just a few clouds. Again, lake-effect cloud will be present in the lee of the lakes.

Sunday will bring mixed skies as the whole storm system begins backing into Northern Manitoba from Ontario. Rain or snow will push through Central Manitoba into the Interlake through the day, spreading cloud ahead of it. Winds don’t look too bad this time – only around 20–30km/h – and precipitation should hold off in Winnipeg until overnight. Temperatures will drop to around 3–4°C on Sunday night, heading into a cool and showery Monday.

Fall-like Weather Returns

After a week of summer-like weather, conditions will return to reality. More fall-like temperatures are expected this week along with some rain.

Cool conditions will dominate our weather on Monday
Cool conditions will dominate our weather on Monday

Monday

Monday
12°C / 8°C
Mainly cloudy

Today will be mainly cloudy with a chance of an isolated shower or drizzle. Low-level moisture under a strong ridge of high pressure will be responsible for the cloud. We may see some clearing late in the day, but that won’t change the day’s expected temperatures. High temperatures today will be in the low teens, with a light easterly to south-easterly wind.

Tuesday

Tuesday
16°C / 10°C
Mainly cloudy

Tuesday will remain on the cool side, with temperatures in the low to mid teens. Despite the fact that these temperatures may seem cool, especially compared to last week, they are actually near normal for this time of year. Our next chance for rain will begin on Tuesday night as a compact, but intense, low pressure system spreads rain over southern Manitoba.

Wednesday

Wednesday
18°C / 8°C
Periods of rain

The aforementioned low pressure system will be the dominant weather feature on Wednesday. It is expected to bring light to moderate rainfall to southern Manitoba for most of Wednesday. It is too early to predict how much rain will fall, but at this point 5-10 mm looks most probable.

Long Range

The long range forecast looks very fall-like. Current modelling suggests we will see normal to below-normal weather as we move into October. That means temperatures in the low teens, plus or minus a few degrees.

Mild Weather Moderating; Rain Returns Sunday

Temperatures will remain well above normal for two more days before seasonal air begins pushing back into the province through the weekend as a cold front gradually progresses southeastwards. A chance for showers returns to southern Manitoba on Sunday as a disturbance developing in North Dakota causes the cold front to stall out over our area.

Friday
28°C / 16°C
Fog patches in the morning, then hot and humid

Saturday
26°C / 12°C
Chance of morning fog, then mainly sunny and warm

Sunday
⇘ 10°C / 6°C
Cloudy with rain likely

First the good news: after we burn off a little fog that developed overnight, today will be another beautiful, summer-like day with highs in the upper 20’s and surprisingly humid conditions for late September. Strong southerly winds at 40–50km/h with gusts as high as 70km/h will be tapping into a pool of moisture in the Northern Plains and drawing it northwards. Dewpoint values will sit near 17–19°C through much of the southern portions of the province.

Today will bring abnormally high late-September humidity to Southern Mantioba.
Today will bring abnormally high late-September humidity to Southern Mantioba.

Yesterday I erroneously tweeted that our dewpoint of 17.6°C broke the previous record of 16.8°C set in 2008 and that it had been the latest on record[1] such high humidity had been seen in Winnipeg. Rob’s Obs did a little digging and found that the actual record is still held by October 8, 1997 when the dewpoint climbed to 18.6°C. Whoops. I apologize for missing that.

That being said, today will give that record a run for its money; multiple models forecast our dewpoint to climb to 19°C, which if it happens would be the latest 19°C dewpoint on record.

Saturday will be a beautiful day in Winnipeg with a high in the mid–20’s and more comfortable humidity as a cold front gradually approaching begins flushing out some of the moisture in the region. There’s a chance of fog again in the morning and we may see a few clouds around, but the bulk of the day should be mainly sunny. Winds don’t look to be an issue.

This simulated RADAR image from the NAM shows a band of rain stretching across Southern Mantioba on Sunday afternoon.
This simulated RADAR image from the NAM shows a band of rain stretching across Southern Mantioba on Sunday afternoon.

Things change on Sunday as the cold front that was approaching on Saturday stalls out as a disturbance in North Dakota develops. A band of rain is expected to develop along the stalled out front, spreading from SW Manitoba eastwards through the afternoon until a band of rain stretches across the whole province. Temperatures will start off cool and only drop from there as the rain cools things off a little further and northerly winds at 20–30km/h continue to tap cooler air and bring it into the region. The rain should taper off late in the evening here in Winnipeg with anywhere from 5–15mm falling depending on the exact timing and speed of the system. Temperatures will dip down to around 6°C.

Unsettled Week Ahead Leading to A Cold Snap

Long-range forecasts don’t look particularly great. The first couple days of the week look seasonal temperature-wise. A series of Colorado Lows look to develop mid-to-late week which will bring a chance for showers, but more significantly, begin drawing down much cooler air from the Arctic. The end of the week looks like it will end with an Arctic outbreak bringing another shot of below-normal temperatures and brisk northwesterly winds.


  1. Records for seasonal dewpoint values go start in 1953.  ↩