Tag: Snow

Clipper-Like System To Bring Snow, Threat of Freezing Rain, to Southern Manitoba

Brad Leave a comment

A clipper-like system ejecting from the Rockies and set to race eastwards across the Prairies will merge with a low pressure system stalled over Southern Manitoba produce widespread snow over the region Wednesday night into Thursday morning.

Cloud cover will increase late this afternoon as the incoming low pushes into southern Manitoba, with an area of precipitation spreading eastwards across the region. Initial phases of precipitation will likely be rain or freeing rain before switching over to snow in the second half of the night. Temperatures will hover near the 0°C mark for much of the night, bottoming out at just –1 or –2°C.

Freezing Rain Potential for December 9-10, 2015
The best chance for some freezing rain tonight looks to run from the Parkland region of Manitoba, eastwards across the Interlake & Red River Valely towards the Ontario border. Freezing rain will be limited south of the international border.
Freezing rain potential exists, but overall it looks like actual amounts would be fairly limited, with just 1–2mm in the worst-hit areas. This will still be enough to make roads quite slippery, though, so if you’re driving tonight, be sure to take extra care.

Snowfall will be limited south of the Trans-Canada highway and likely more characterized by a passing band of snow, then a pause before wrap-around snow pushes in on the back-side of this system. Further north, somewhere near the Trans-Canada highway, a west to east band of snow will set up along the northern edge of the low track and will produce the most snow, with general amounts of 5–10cm expected. There will be the risk of amounts in the 10–20cm range for localized areas of upslope flow along the eastern slopes of the Riding Mountains.

AWM Storm-Total Snowfall Forecast valid December 10, 2015
A swath of 5-10cm of snow is expected across Southern Mantioba by the end of tomorrow afternoon.
The snow will continue falling through much of Thursday here in Winnipeg and the Red River Valley before tapering off in the evening. The snow will be accompanied by gusty northerly winds of 30 gusting 50km/h. Expect the winds to taper off and skies to clear on Thursday night with temperatures dropping to about –6°C.

Friday will be a relatively nice day, however we’ll be stuck between a low pressure system passing to our south and an Arctic ridge to our north. This will keep temperatures limited to around –3°C for a daytime high and bring a chance of some flurry activity through the afternoon as mixed skies develop over the region. Fortunately, winds won’t be too much of an issue. Clouds will likely hang around on Friday night as we head to a low near –7°C.

Long Range

While the cooler temperatures in the forecast may be disappointing to some who have been enjoying this stretch of incredible early-winter warmth, there’s not too much room for complaining as the overnight lows this week are just dipping towards what the normal daytime high is for this time of year.

There’s some uncertainty as to what the weekend will bring, but overall it should be a fairly quiet weekend with seasonal to slightly above seasonal temperatures. Little to no snow is expected.

NAEFS 8-14 Day Temperature Anomaly Forecast
The NAEFS is forecasting a return to above-seasonal temperatures in the 8-14 day time span.
Over the next week, no additional snow is expected, and again, above-seasonal temperatures are expected to build back into the region. The fresh snowpack that will develop after tonight’s snow will likely preclude significant stretches of above–0°C weather, but with daytime highs dropping by the day, it’s nice that the –30°C deep freeze isn’t anywhere to be seen.

A Brief Cold Snap Before Weekend Warmth

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The passage of a low pressure system to the east of Winnipeg this morning will usher in cooler air as an Arctic ridge of high pressure builds in across the Prairies. As the ridge builds over Manitoba, temperatures daytime highs will end up falling quite a bit below the seasonal value of –5°C for this time of year, possibly not even breaking the minus double-digits on Thursday. The colder weather will be short-lived, however, as a potentially breezy Saturday holds promise of returning above-seasonal temperatures to the region just in time for the 103rd annual Grey Cup on Sunday.

Temperatures will be on a downward slide today as northerly winds to around 30km/h—with gusts up to the 50km/h mark—usher in cooler air and a large ridge of high pressure sourced from the Arctic. There will be some light snow or flurries around this morning, but they’ll be light and should taper through the morning. By supper time, temperatures will have fallen to around –7°C with the northerly winds still blowing. Heading into the overnight period, the winds will start to taper off with the cloud cover breaking up a bit, but there will be plenty of cloud streaming southwards off Lake Manitoba & Winnipeg through the night.

RDPS Surface Pressure Pattern for 12Z Thursday November 26, 2015
By Thursday morning, a large ridge of high pressure will be moving over Southern Manitoba.

Thursday may end up being the coldest day so far this November with temperatures struggling against the Arctic air entrenched over the region. Temperatures will climb to around –10°C by the afternoon with winds out of the north to around 20km/h. Skies will be partly cloudy thanks to a continued stream of cloud cover coming off of the lakes, in particular Lake Winnipeg. If you find yourself underneath any of the lake cloud, you’ll likely see some snow, however it looks fairly light and probably won’t accumulate much. Temperatures will dip to only about –13°C on Thursday night as slightly warmer air begins moving in as the ridge slumps to our south.

Seasonal weather will return to Winnipeg on Friday with mainly sunny skies and a high near –6°C. Winds will be fairly light. Temperatures will fall to around –9 or –10°C on Friday night with winds picking up out of the south.

Looking Towards the Grey Cup

The story for this weekend will be warmer weather returning to Southern Manitoba. On Saturday, gusty westerly winds will bring daytime highs approaching –2 or –3°C.

Grey Cup Sunday is a bit of a trickier forecast at this point, but the best guess I have this far out is that temperatures will likely be seasonal with a high somewhere near –6°C or so and light winds. By the time the football game starts, temperatures will probably be somewhere near the –10°C mark, so bundle up!

Winter Settles In

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After the blustery entrance of winter that saw the first substantial snowfall of 2015 in the Red River Valley alongside winds gusting anywhere from 70 to 90 km/h, significantly cooler weather will settle over the region for the coming days. There good news is that temperatures won’t be too far from seasonal for this time of year, despite being nearly 15°C colder than they were earlier this week.

Mainly cloudy skies will persist through the Red River Valley today with northwesterly winds of 20–30 km/h with gusts up to around 45–50 km/h. The snow we’ve seen the past couple days is over, but a couple light flurries can’t be ruled out through the day; that said, it wouldn’t be much that will accumulate. The only threat of accumulating snow will come as the winds align and lake-effect snow develops off of Lake Manitoba and Lake Winnipeg. Who will see the snow will depend on exactly what the wind direction is, and at the time it looks like Winnipeg may see a bit of snow from these features. Daytime highs will be slightly below the seasonal normal of –3°C, topping out at –5°C or so.

RDPS 12hr. Precipitation Accumulations
The RDPS precipitation totals for today clearly show the two bands of lake-effect snow off of lake Winnipeg & Lake Manitoba.

The clouds will start breaking up tonight as we head towards a low of –12 to –15°C.

Saturday brings less wind, a little less cloud, but more cold. Mixed skies will preside over a day that sees temperatures climbing to –6°C or so and calm winds. The cooler, calmer weather is thanks to a ridge of high pressure that will be sliding through the area. Despite the cooler weather, the lack of significant winds and a bit of sunshine may end up making Saturday a relatively pleasant day overall. Expect a low near –12°C under partly cloudy skies on Saturday night.

GDPS 12hr. Precipitation Accumulation valid midday Sunday through Sunday evening.
The GDPS is showing a large area of snow pushing through Manitoba on Sunday afternoon and evening.

Sunday’s weather will be largely influenced by the approach of the next low pressure system to impact Winnipeg and the Red River Valley. Starting fairly early in the morning, winds will begin picking up out of the south and will strengthen to around 30–40 km/h by midday.[1] Cloud cover will push in from the northwest while temperatures climb close to the freezing mark. By later in the afternoon, it appears that there will be a fairly good chance that the Red River Valley will see an area of snow push through, possibly dropping another couple cm over the region.

  1. At this point, winds of 30–40 km/h seem reasonable, however if a little more cold air damming occurs in the Red River Valley, which will dependent on the exact track and strength of the ridge of high pressure moving through on Saturday, then stronger winds of 40–50 km/h could possibly develop. We’ll keep an eye on it as the weekend progresses.  ↩

Winter Arrives

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Environment Canada made headlines with the special weather statement for Winnipeg issued Monday with a referential start: winter is coming. And how.

Today will mark the beginning of a harsh slide into winter after a essentially a month of temperatures well above seasonal for this time of year. The change in the pattern will be brought courtesy a rather peculiar weather setup that will see a relatively weak Colorado Low moving north through Minnesota into Northwestern Ontario merge together with an Alberta Clipper quickly moving eastwards across the Prairies. Each system is moderately potent in their own right, but when combined, they will form a new storm system that will rapidly intensify, driving strong northwesterly winds through the province alongside the first significant snowfall for many regions of Southern Manitoba.

Today will start deceptively. Relatively light winds and temperatures climbing towards 5 or 6°C will give a false sense of security betrayed only by the increasing cloud cover that will build in through mid-day into the afternoon. Some light rain will develop over the Red River Valley this afternoon, which will mark the end of our above-seasonal temperature streak and usher in winter. As the rain moves into the region, winds will pick up out of the northwest to around 50km/h sustained with gusts as high as 70–80km/h. The rain will switch over to snow sometime in the evening and likely begin piling up fairly quickly as the strong winds rapidly cool the ground and other surfaces.

The strong winds and snow will persist through tonight as temperatures dip down towards –3°C or so as colder air begins filtering into the region. With snow piling up and such strong winds in place over the Red River Valley, it’s quite likely that driving conditions become quite poor as roads freeze, become ice covered, and see reduced visibility in blowing snow.

AWM Snowfall Forecast issued November 18, 2015
AWM Snowfall Outlook issued November 18, 2015

Thursday will continue to bring light snow and strong winds to the region as temperatures remain around –4°C or so. The winds will be a bit lighter than at their peak, but will likely remain near the 40 gusting 60km/h mark through much of the day before beginning to taper off in the evening. Overnight, other than some lake-effect snow streaming southeastwards off of Lake Winnipeg, there’s likely to be just a few flurries lingering in the region. Temperatures will dip down to –6°C for the overnight low.

In general, around 5–10cm of snow is likely to fall with this system through southeastern Manitoba, the Red River Valley and northwestwards into Parkland Manitoba. Exact amounts will depend on the timing of the change-over from rain to snow and how quickly the snow begins accumulating instead of melting on the ground.

Friday will be a mainly cloudy day with just a very slight chance of light, scattered flurries. Temperatures will recover only a degree or two from the overnight low with highs around –4°C. There may be a few clear breaks through the Red River Valley on Friday night, but overall there will still be a fair amount of cloud as temperatures head towards an overnight low near –10 or –11°C.

Colder Weather Continues Through The Weekend

The cooler weather, which while a significant drop from what we’ve been experiencing is, in actuality, just a couple degrees below seasonal values for this time of year, will persist through the weekend.

NAEFS 8-14 Day Temperature Anomaly Outlook valid for November 25 to December 2, issued 12Z November 17, 2015
The NAEFS is showing a trend towards seasonal temperatures for the remainder of November.

Daytime highs around –5 or –6°C will be in place over Winnipeg & the Red River Valley this weekend, with a chance of some more flurries on Saturday improving to sunnier fare on Sunday. Overnight lows will be in the low minus single digits. So, while it may be a huge change from the weather we’ve been having, we’ll be shifting to more seasonal weather for the end of November.