Tag: Lake-Effect Snow

Winter’s On The Way

Brad Leave a comment

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.  ↩

Stuck In A Cool Pattern

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A high-ampltude jet stream is bringing unseasonable weather to much of Canada.

A high amplitude jet stream is bringing unseasonable weather to much of Canada.

Temperatures will remain fairly cool through the next few days as Southern Manitoba remains entrenched in a pattern that has the jet stream diving through Saskatchewan well to our south, trapping cooler air over the area. In addition, snow will enter the picture as snow squalls batter areas in the lee of the lakes – in particular Lake Winnipeg – and a weak disturbance slides down from the North and brings flurry activity to many regions tonight.

Today

Wednesday

3°C
Mainly cloudy. Chance of flurries in the afternoon.

Through much of the Red River Valley today we’ll see mainly cloudy skies – perhaps with a sunny break or two – with the weather pattern being dominated by snow squalls coming off the lakes. While some squall activity is expected off of Lake Manitoba, with a band of snow extending SSE from the lake positioned between Portage la Prairie and Elie. More vigorous activity is expected off of Lake Winnipeg, where cooler air aloft will combine with favourable winds which will bring air not just over the South Basin, but over the North Basin as well. The cooler air aloft coupled with the air being over water for longer will combine to produce vigorous convection that will push SSE off the lake into areas around Beausejour and east.

The snow has the potential to be very heavy, producing near-whiteout conditions and rapid snowfall accumulation. Fortunately it will be confined to a fairly narrow corridor in the lee of the lake, but if you are expecting to travel east towards the Whiteshell today, you should be prepared for potentially encountering treacherous winter driving conditions.

Wednesday Night

-2°C
Light snow beginning in the evening.

Embedded above these local features will be a weak frontal wave sliding southwards along the baroclinic zone that is dividing the Prairies. This weak wave will bring light snow activity to the Interlake through the daytime today, pushing southwards and entering the northern Red River Valley by late in the afternoon or early evening hours. This light snow will push all the way south to the US border through the evening and persist through much of the night. No significant accumulation is expected from this system, although if it ends up intense enough then its possible some areas may awake to a cm or two on Thursday morning.

High temperatures will be around 2–3°C today throughout the Red River Valley while the ample cloud cover and light snow will limit our overnight lows to just around –2°C.

Thursday & Friday

Thursday

4°C / -4°C
A mix of sun and cloud; chance of flurries in the morning.
Friday

7°C / 0°C
Sunny becoming a mix of sun and clouds. Chance of showers.

Thursday will bring a mix of sun and cloud as the cloud from the overnight snow clears out but ample low cloud continues to flow off the lakes. There will be a chance of flurries in the morning as the overnight disturbance leaves the province, but little is expected otherwise. Some light snow may fall out of any clouds that wander through Winnipeg in the afternoon, but it would likely be exceptionally light if that were to happen.

Overall it will be a relatively nice, albeit cool, day. We’ll drop down to around –4°C under partly cloudy skies on Thursday night.

Friday will start with relatively clear skies but we’ll see things become more mixed as the day progresses. A significant low pressure system will be pushing through Northern Manitoba into NW Ontario dragging warm air with it across the Prairies; we’ll see southwesterly winds of 20–30km/h bring warmer air into the region as we head to a seasonal high of 7°C. There will be a chance of showers here in Winnipeg, although we look to be on the periphery of the system with the bulk of the precipitation falling through the Interlake into Southeast Manitoba. Friday night will bring partly cloudy skies and a low of about 0°C.

Cool Weekend Ahead

Brad Leave a comment

Arctic air will keep temperatures cool through the weekend with daytime highs some 5-7°C below normal. Scattered flurries will be common through the weekend, while a significant lake-effect snowfall event will impact portions of the Whiteshell and Eastern Manitoba.

850mb Temperatures Valid Saturday Morning

850mb temperatures valid Saturday morning. A deep pool of Arctic air will flood across the Prairies this weekend.

As the low that brought rain to Southern Manitoba the past few days pushes northwards into Hudson Bay, it will intensify quite considerably1 and induce a strong northwesterly flow over the Canadian Prairies. This cold air will likely produce isolated scattered flurries, however the largest effect will be strong lake-effect snow bands, primarily from the basins of Lake Winnipeg. These lake-effect bands will mainly effect the Bisset region and slowly push northwards towards Berens River as the winds back slightly to westerly through the weekend. Substantial amounts of snow are possible with these bands, with the potential for anywhere from 15-30cm of snow possible in areas that see a band have a particularly long residence time over them.

Daytime highs over the next few days will sit within a degree or two of 0°C, with overnight lows near -6 or -7°C. No significant improvement in temperatures is expected until potentially early next week as a low pressure system moves through the Central Prairies and brings ever so slightly warmer air back to the region.

  1. It’s currently forecast to deepen from a 982mb low this morning to a 967mb low tomorrow morning. ↩

More Snow On The Way For Southern Manitoba

Brad Leave a comment

A system tracking across the Northern Plains of the United States will bring another shot of snowfall to Southern Manitoba tonight and tomorrow.

A low pressure system in Montana has pushed snow into most of North Dakota and is beginning to push the snow northwards towards the International border.  Snow should be slow to start this evening, with a dry northeast flow undercutting the moisture pushing up into Southern Manitoba, but by mid-to-late evening, the snow should have pushed all the way up to Winnipeg.


12Z GEM-REG Model Output Valid 12Z Sunday Morning (12H QPF)

Residents in Winnipeg can expect to see close to 5cm of snow fall on their freshly plowed streets, while areas closer to the border, such as Morden, Gretna, Altona, and Steinbach, will see closer to 7-10cm tonight.  The show will be lighter tomorrow, with only another 2-4cm falling in most areas.  Current indications are that this event won’t deliver warning-level amounts of snow; however people near the U.S. border will want to keep an eye on what Environment Canada does.

As the system moves out on Sunday, a concern again will be lake-effect snow flurries.  The sudden onset of cold weather is allowing the lakes to produce heavy flurries giving near-zero visibilities at times.  The exact location is too early to tell, however it looks like Winnipeg may be spared from them, with a more northerly wind expected behind the system.

After this, cold weather will return until mid-week, when it looks like there is another chance for snow.

Drive safe!