Tag: Cooling Trend

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.  ↩

Warmer than Normal, but Still Cool

Scott Leave a comment

Conditions will remain at or above normal this week, unfortunately “normal” continues to get colder by the day.

A cool westerly flow will dominate southern Manitoba on Monday

A cool westerly flow will dominate southern Manitoba on Monday

Monday

Monday
8°C / 2°C
Mix of sun and cloud

Today will be mild by early November standards, but that doesn’t mean it will be warm. Temperatures will be in the mid to upper single digits in southern Manitoba with a brisk westerly wind. Skies will be a mixture of sun and cloud as an upper-level weather system moves across Manitoba.

Tuesday

Tuesday
4°C / 0°C
Mainly cloudy with chance of showers or flurries

Tuesday will be cooler than Monday as we see a brisk north-westerly flow behind a departing low pressure system. Temperatures will generally be in the mid single digits under mainly cloudy skies. There may be a few flurries or rain showers, but no significant accumulations are expected.

Wednesday

Wednesday
3°C / 1°C
Mainly cloudy with chance of showers/flurries

Wednesday will see continued cool weather in southern Manitoba with temperatures in the low to mid single digits, but lighter winds than what we saw earlier in the week. Skies will remain mainly cloudy and we may once again see some light flurries or rain showers.

Long Range

The long range forecast suggests we’ll continue to see normal to above-normal weather for at least the next week or so. Beyond that model solutions diverge, with equal chances of us ending up above or below normal.

Pleasant Weekend Before Big Cool Down

Brad Leave a comment

After a dreary evening last night, conditions will gradually improve to quite a pleasant weekend for Winnipeg & the Red River Valley.

The RDPS model is forecasting a line of showers & thunderstorms through the Red River Valley by 5-7PM this evening.
The RDPS model is forecasting a line of showers & thunderstorms through the Red River Valley by 5–7PM this evening.

Today will start off with a bit of cloud through the Red River Valley thanks to the Manitoba lakes. We won’t see completely sunny skies, though, as a combination of increasing instability and some cloud moving in ahead of a trough moving across the province produce mixed skies through much of the day.

Friday
18°C / 5°C
Increasing cloud; a chance of showers or thunderstorms in the afternoon.

This afternoon into early this evening will bring a slight chance for showers or thunderstorms across the Red River Valley as that trough line works its way through the region. At this point it doesn’t look like severe weather is likely. Once the trough swings through, northerly winds at around 30km/h will move into the region and general clearing will take place.

Cooler air aloft will once again slump over Southern Manitoba tonight, bringing with it a chance for lake-effect cloud and drizzle once again. Winds, in general, don’t look particularly favourable which will likely limit or exclude their development. Winds will taper off overnight and low temperatures will be near 4 or 5°C.

Improving for the Weekend

Saturday
21°C / 8°C
Cloudy periods

Sunday
23°C / 12°C
A few clouds

Warmer weather will move in for the weekend as multiple low pressure systems draw warmer air eastwards across the Prairies as they move across Central Manitoba. Precipitation is expected to remain through Central & Northern Manitoba, leaving us dry with seasonal highs in the low 20’s. Overnight lows look to dip to around the 10°C mark, give or take a couple degrees.

Big Cool Down Next Week

Unfortunately, the pleasant weather will not be sticking around. Colder air builds into the Northern Prairies behind the systems tracking through during the weekend, which will then be driven southwards early in the week as an Alberta-clipper type system races across the Prairies.

The CPC 6-10 day temperature & precipitation anomaly outlook calls for below normal temperatures and near- to slightly above-normal precipitation.
The CPC 6–10 day temperature & precipitation anomaly outlook calls for below normal temperatures and near- to slightly above-normal precipitation.

850mb temperatures are forecast to drop into the 0°C to –5°C range by mid-week, resulting in daytime highs dropping towards the low teens and overnight lows likely dipping towards the 0°C mark. By mid-week, frost will be a definite concern across Western Manitoba and into the Red River Valley. The big question here in Winnipeg & the RRV will be exactly how much cloud the lakes produce when the cold air slides over them.

At this point it looks like a brief moderate at the end of the week before another cold blast potentially moves through.

Major Low Brings Cooler and Unsettled Weather

Brad Leave a comment

A major low pressure system developing in the United States and forecast to lift northwards into the Eastern Prairies through the weekend will bring generally unsettled weather ahead of a more cohesive area of precipitation that will move through on Saturday night.

Friday
22°C / 15°C
Mostly cloudy with a chance of scattered showers

Saturday
19°C / 15°C
Mostly cloudy

Sunday
23°C / 15°C
Rain ending in the morning; sunny breaks with a risk of strong-to-severe thunderstorms thereafter

Perhaps the single most important thing to keep in mind with today’s forecast is the fact that weather models have little consensus on what’s going to happen over the next few days other than the fact that there will be a large low pressure system that will impact an area somewhere between the Rocky Mountains and the Great Lakes.

That being said, it looks like the next several days will bring mixed weather to Winnipeg. Today will see a chance for scattered shower activity as a weak shortwave rolls across the Red River Valley, but nothing nearly as bad as what hit the city last night, where up to 80mm of rain fell in a rapid deluge through portions of the city that resulted in wide-spread flooding through the hardest hit areas.

Temperatures will climb to around 21 or 22°C this afternoon with a light wind out of the north. Tonight will be mainly cloudy with fairly light winds and a low near 15°C.

Saturday: The Low Approaches

Tomorrow will see mainly cloudy skies with a high of just 19 or 20°C. Winds will pick up out of the northeast to 30-40km/h as the main low pressure system for the weekend strengthens and lifts northwards through the Dakotas. By supper time, rain with the chance for embedded thunderstorms will spread through North Dakota into Southern Manitoba, reaching Winnipeg later in the evening.

The RDPS is forecasting an intense convective complex with substantial rainfall amounts on Saturday night. Who knows if it's correct.
The RDPS is forecasting an intense convective complex with substantial rainfall amounts on Saturday night. Who knows if it’s correct.

The rest of Saturday night will be quite rainy with 10-20mm of rain likely across most of Southern Manitoba with localized amounts in excess of 30-40mm due to embedded convection in the precipitation shield. Some models, such as the RDPS pictured above, want to produce upwards of 50-75mm of rain, although at this point that’s likely overdone and a symptom of what’s known as “convective feedback” in the model, something that ends up causing the model to produce too much precipitation when there is widespread convection occurring. Temperatures will drop to around 15°C again with winds out of the northeast at around 30km/h.

More Unsettled Weather on Sunday

The weather on Sunday will likely improve as the low pressure system lifts through the Red River Valley and pushes off to our northeast. Rain will taper off in the morning and Winnipeg will be left under mostly cloudy skies in what’s known as the “dry slot” — the area behind the cold front located between the frontal precipitation and wrap-around precipitation denoted by descending dry air aloft. The high will climb to around 22°C with some strong northeasterly winds becoming light in the afternoon.

Significant instability associated with the low pressure system will be in place, and even with temperatures climbing only into the low 20’s, it will be enough when coupled with the significant moisture in place to present a risk for strong-to-severe thunderstorms. We’ll have more information in the comments on Sunday.

Things will begin to clear out on Sunday night as the temperature drops to around 13°C.

Into next week looks fairly benign with temperatures gradually returning towards normal by week’s end. There will be a couple cool nights in the coming week with overnight lows dipping into the single-digits.

We’ll be keeping an eye on this system as it develops; slight alterations in the track of the system could dramatically impact forecasts, so if any changes are needed we’ll note them below in the comments. All in all it will be a mediocre weekend followed by an improving week.