Tag: Blowing Snow

Major Winter Storm Moving In

Scott 1 Comment
Environment Canada has issued a Winter Storm Warning for this system.

A major winter storm is moving in as you read this article. It will bring the first serious snowfall of the year to the Red River Valley, with heavy blowing snow or even blizzard conditions possible in many areas. You may want to reconsider any travel plans early this week!

A strong low pressure system will bring heavy snow and strong winds to southern Manitoba early this week
A strong low pressure system will bring heavy snow and strong winds to southern Manitoba early this week

Today

Monday
0°C / -2°C
Snow beginning

A strong low pressure system will move off the Rocky Mountains and into North Dakota today. It will spread moderate to heavy snowfall into parts of western Manitoba this morning, before snow spreads over the rest of southern Manitoba later in the day. Snowfall will fall for the entire day in most of western Manitoba, with total accumulations of 10-15 cm expected in most areas. Further east, the Red River Valley will see lesser amounts today, with 2-5 cm in the Winnipeg area and more like 5-10 cm near the International border. Local amounts of 15 cm may occur along the International border in south-central Manitoba. Winds will be gusty from the east at 20-30 km/h, producing some blowing and drifting snow.

Tuesday

Tuesday
-2°C / -4°C
Blizzard Developing with Heavy Snow

Conditions will really begin to deteriorate early Tuesday as winds shift to the northwest. Snow will continue to fall as well, with an additional 10-20 cm possible in the Red River Valley on Tuesday. Snow will taper off in southwestern Manitoba, but another 2-5 cm will be possible. The northwesterly winds that develop will be strong at 40 km/h gusting to 60 km/h, with higher values of 50 km/h gusting to 70 km/h in some treeless areas. This will likely result in blizzard conditions over large parts of southern Manitoba, especially south and west of Winnipeg. Those areas that don’t quite meet blizzard criteria will certainly see heavy blowing and drifting snow, with travel becoming difficult or impossible in some areas. Road closures are likely, especially the Trans-Canada Highway west of Winnipeg and Highway 75 south of Winnipeg. Conditions will not improve significantly until early Wednesday.

Expect storm-total snowfall accumulations by Wednesday morning.
Expect storm-total snowfall accumulations by Wednesday morning.

Wednesday

Wednesday
-12°C / -20°C
Snow and blizzard ending

Snow should finally taper off on Wednesday morning in all of southern Manitoba, but not until most areas have received significant accumulations of snow. Southwestern Manitoba can expect 15-25 cm, while Winnipeg can expect 10-20 cm. Areas along the International border in south-central Manitoba can expect to receive 20-30 cm. Locally higher amounts may occur where heavier bands of snow persist for a longer period of time. Large snow drifts will be a problem on Wednesday, even once the snow ends. Some rural roads may be impassable due to heavy drifting. Blowing snow will persist on Wednesday, but winds will slowly decrease throughout the day. Temperatures will have dropped noticeably on Wednesday as this system begins to pull down a cold arctic air mass.

Long Range

Conditions will finally calm down on Thursday as winds taper off. However, in the wake of this strong low we’ll see a blast of arctic air, with temperatures likely dropping into the minus twenties on Thursday and Friday. This frigid pattern is expected to persist for awhile, so make sure to get out those winter clothes!

Weekend Storm To Bring Snow & Warmer Weather

Brad Leave a comment

Warm weather is on the way for Winnipeg this weekend as a strong low pressure system developing over Northern Alberta spreads mild air eastwards through the Prairies. This storm system will then slide southeastwards across the Prairies, bringing a moderate snowfall event to Manitoba primarily through Saturday afternoon and Sunday, followed by falling temperatures, gusty winds and blowing snow.

Winnipeg will see mainly cloudy skies today as the city remains locked underneath a tight baroclinic zone. [1] There will be a continued chance of occasionally seeing some of the flurry activity that developed last night over the city, however no real accumulations of snow are expected today. Temperatures will be fairly pleasant with a daytime high near -6°C, which is 4°C above the normal high of -10°C for this time of year.

The chance for any flurry activity will diminish tonight, but the cloud will stick around as temperatures dip to around -11°C for the overnight low.

Storm System Moves in on Saturday

Saturday will bring the arrival of both warmer weather and the storm system that will bring a new batch of snow to the region. First the good news: temperatures will be on their way up through the entire day. From the morning low near -11°C, temperatures will gradually climb to near -5°C midday and then up to near -1°C by evening. Temperatures will then remain fairly steady through the night, wavering around the -1°C mark. Cooler air will begin working into the region on Sunday, dropping the temperatures in Winnipeg to around -8°C by the evening.

AWM Snowfall Forecast for February 6/7, 2016
Updated AWM Snowfall Forecast for February 6/7, 2016 (Original here)

While some flurries are possible through the morning, the real snow will develop through the afternoon hours as the low centre of the storm begins moving into Southern Manitoba. Snow will intensify into the evening and the heaviest snow of the storm will be through Saturday night. On Sunday morning the snow will likely begin to ease, but continue to persist much of the day. By the time all is said and done, it looks quite likely that essentially all of Southern Manitoba will have seen at least 5cm of new snow before things taper off on Sunday night.

The heaviest amounts will fall to the north of the low track, which, given that it’s still a day and a half out, could change. The current agreement seems relatively dependable, however if it does end up shifting south even just a little, it’s possible that Winnipeg could surpass 10cm.

Although this system has the potential of producing a lot of snow, it doesn’t look like it will qualify for a snowfall warning from Environment Canada, which requires 10cm to fall within a 12hr. time period. This system will produce higher amounts more through it’s longer residency time than its intensity. That said, it’s still early for a lot of things with systems like these; we’ll be keeping an eye on it and updating forecasts if it looks like it’s going to change significantly from current expectations.

Lastly, there will be a bit of wind with this system too. Winds won’t be too bad on Saturday, however for a short while in the afternoon winds may climb up to around 30-40km/h out of the southeast. Winds will diminish overnight before picking up on Sunday out of the northwest. Blowing snow will be an issue on Sunday as the northwesterly winds increase to 40 gusting 60km/h and combine with the fresh snow. Through the Red River Valley, the strong winds will be in place by mid-day Sunday and persist into the late evening hours, so if you have plans to travel on Sunday afternoon or evening, prepare to give yourself some extra time to account for poor visibilities and driving conditions. For those reading this in southwestern Manitoba, the stronger winds will be in place by Sunday morning and persist into the overnight period as well, making blowing snow an issue all the way west into southeastern Saskatchewan.

Long Range: Colder Weather…But Only Briefly

Behind this storm system, cooler air will begin slumping into the Prairies, returning temperatures to seasonal values. Another batch of snow is possible Tuesday night as another disturbance moves through the region, which will usher in a pattern change that will see southwestern Manitoba clipped by several systems while even colder air works into the Prairies.

NAEFS 8-14 Day Temperature Anomaly Forecast — Valid February 13-20, 2016
NAEFS 8-14 Day Temperature Anomaly Forecast — Valid February 13-20, 2016

Into the second half of next week, below-seasonal temperatures will begin moving into the province with daytime highs slumping into the low minus teens and overnight lows dipping below -20°C. This cooler weather will likely persist into the early parts of the following week before a moderating trend begins, shown by the higher probabilities of cooler-than-normal weather in the NAEFS forecast above.

The seasonal daytime high for February 5th in Winnipeg is -10°C, while the seasonal overnight low is -21°C.

  1. A baroclinic zone is an area where there is a strong temperature gradient across relatively short distances, either at the surface or aloft.  ↩

First Major Snowstorm of the Winter Incoming

Brad 5 Comments

Southern Manitoba has its first major snowstorm of Winter 2015/16 on the doorstep as a Colorado Low moves northeastwards through the American Plains and is poised to produce 10–20 cm of fresh snow through the Red River Valley.

The incoming Colorado Low has spread snow across South Dakota this evening which is now pushing into North Dakota and Minnesota. This area of snow will intensify as it heads northwards courtesy a steadily organizing weather feature called an inverted trough. This trough of low pressure extends north/northwest out from the centre of the Colorado Low and will draw moisture into the Red River Valley and produce a swath of heavier snow through the region.

Mayville RADAR @ 10:29PM CST on December 15, 2015
At 10:29PM CST, Mayville RADAR in North Dakota shows a broad area of snow pushing northwards towards Manitoba.

At this point, it looks like the snow will begin pushing across the U.S. border sometime between 2 and 4 A.M. and then spread into Winnipeg before 4 and 6 A.M.. The heavier snow will build into the Red River Valley between 6 and 9 A.M. and persist until near lunch time. Through the first half of the day, as much as 10 cm could fall; that’s a fairly intense snowfall rate and will undoubtedly have significant impacts on transportation. The snow will ease slightly for the afternoon, but still be fairly persistent, dropping another 2–5cm or so.

Winnipeg Forecast Sounding for 11Z December 16, 2015
The forecast soundings for Winnipeg on Wednesday morning show very favourable thermodynamic profiles for moderate to heavy snow.

Heading into the evening and overnight hours, the snow will begin to become a little bit more disorganized save for one area known as the deformation zone. This feature will be the western-most extent of the snowfall and will typically have slightly more organized precipitation along it. Best indications at this point are that the deformation zone will line up through the Interlake and Red River Valley, meaning it’s fairly likely that more persistent light snow will last through the night. This snow could produce anywhere from 1–3cm more.

AWM Snowfall Outlook for December 15-17, 2015
AWM Snowfall Outlook for December 15-17, 2015 with verification overlaid.

By Thursday morning, the snow should be tapering off to flurries and moving out of the region. When all is said and done, it’s likely that anywhere from 10 to 20cm of fresh snow will have fallen in the Red River Valley. Localized amounts could possibly exceed 20cm in a few particular locations, namely anywhere that may see upslope enhancement in the northerly winds: the western escarpment of the Red River Valley and north side of Turtle Mountain being to of the most likely places. These higher amounts would be very localized, though, and are not reflected in the above snowfall forecast, which is looking more at large-scale snowfall totals.

Snowfall Warning Highlights
The highlights of this Colorado Low storm system

Environment Canada has issued a snowfall warning arcing across the Red River Valley with the discussion showing very similar thinking: 10–20cm of snow, heavy first thing Wednesday morning, then blowing snow and cooler temperatures heading into Thursday.

Cooler with Blowing Snow Behind the Colorado Low

Beginning Wednesday evening, northwesterly winds will begin moving into southern Manitoba. Despite the cooler temperatures pushing in and the relatively strong winds aloft, winds will likely only reach around 30 gusting to 50 km/h overnight.[1]

By Thursday morning, the wind will strengthen to 40 gusting 60 km/h, which when combined with the fresh snow, will almost undoubtedly produce fairly widespread blowing snow through the Red River Valley. These stronger northwesterly winds will also be ushering in a much cooler air mass that will drop temperatures to –20°C by Saturday morning.

This colder weather, while an abrupt change from what we’ve been seeing for the past month and a half, is actually not all that uncommon. Normal daytime highs for Winnipeg this time of year are around –10°C with normal overnight lows near –20°C. So while we’ll see temperatures dropping 10–15°C, they’ll be seasonal to just slightly below seasonal for this time of year.

Fortunately this cold snap will be brief. Early next week it looks like a weak system will move through bringing a chance for some light snow and a return to slightly above-seasonal temperatures.

  1. This is due to the cyclonic curvature of the surface pressure gradient which can act to diminish wind speeds.  ↩

Winter Arrives

Brad Leave a comment

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.