Alberta Clipper Plunges Manitoba Into The Deep Freeze

Brad Leave a comment

An Alberta Clipper moving through the province on Friday into Saturday will pack a potent punch – likely the worst storm so far this winter for most places, including Winnipeg – bringing a decent shot of snow alongside strong winds producing significant blowing snow. To cap things off, a bitterly cold air mass will move into the region bringing extremely cold temperatures & wind chill.

Friday
-14°C / -21°C
Early morning flurries, then snow beginning late in the day
Saturday
⇓ -26°C / -32°C
Snow tapering off then clearing; windy & cold
Sunday
-27°C / -33°C
Mainly sunny

Friday will start off mainly cloudy as a brief shot of light snow exits the province. Amounts from this band will be just a couple cm or less and this leading impulse will be nothing compared to what will be moving in later in the day.

Before that, though, skies will become more mixed with temperatures gradually climbing to around –14°C. Winds will remain relatively light until the Alberta Clipper moves into the region tonight.

Snow will push into Southwestern & Parkland Manitoba this afternoon and quickly spread eastwards across the remainder of the province by the evening. Snowfall will be quite intense, with rates reaching as much as 2cm/hr in the heaviest band. The heaviest snow will fall through Friday night and then taper off from west to east through the day on Saturday.

Expected snowfall totals across Southern Manitoba. The heaviest snow is expected to fall within 50km or so on either side of the U.S. border.
Expected snowfall totals across Southern Manitoba. The heaviest snow is expected to fall within 50km or so on either side of the U.S. border.

By the time the snow tapers off on Saturday, up to 25cm of snow may have fallen through the heaviest band of snow which is centered along the international border and cuts across the Southern Red River Valley. Winnipeg will likely receive on the higher end of 10–15cm of snow while amounts then taper off through the northern Parkland region and central Interlake.

Measuring that snow may be quite difficult, though, as strong northwesterly winds to 40km/h move into the Red River Valley. With all the fresh snow, widespread blowing snow is very likely on area highways with the potential for significant restrictions to visibility. In areas of the southern Red River Valley, we may even see the development of a full-on blizzard with the higher amount of fresh snowfall and slightly stronger winds due to the funnelling of the valley. Driving conditions will likely be quite poor, so be sure to give yourself plenty of additional time if you need to travel and remember to always carry a winter survival kit in your vehicle.

There’s only one story once the snow tapers off on Saturday and skies begin to clear: bitter cold. It’s going to get very, very cold across the entire province with the coldest air mass of the season diving southwards behind the clipper. Saturday will see temperatures slipping through the day to around –26°C which will then plummet down to –32 or –33°C overnight. With winds of 10–20km/h persisting overnight, wind chill values of –40 to –45 will be widespread through Southern Manitoba.[1]

Sunday will bring barely any recovery with temperatures struggling to get to a paltry –27°C. Expect the low on Sunday night to dip back down to –32 or –33°C with wind chills agin in the –40 to –45 range.

No Warmth In The Long-Range

Looking ahead to next week, conditions look dry with little to offer as reprieve from the cold. Daytime highs will moderate towards the –20°C mark, but overnight lows in the low minus-twenties will be sticking around for a while.

The NAEFS 8-14 day temperature anomaly outlook.
The NAEFS 8–14 day temperature anomaly outlook.

Looking even further ahead, there are little in the way of strong signals. There’s about a 50/50 chance of below-seasonal temperatures continuing, but compared to this week, it’s at least a trend towards more seasonal temperatures. It’s not much, but when we’re getting as cold as we will this weekend, I’ll take what I can get.

  1. This will likely result in an extreme cold warning being issued by Environment Canada, as their criteria is a temperature or wind chill colder than –40.  ↩

Southern Manitoba 2014 Thunderstorm Statistics

Julien Leave a comment
This photo of a funnel cloud was taken just southwest of Winnipeg.
This photo of a funnel cloud was taken just southwest of Winnipeg.

Welcome to our summary of the 2014 thunderstorm season across Southern Manitoba! This post will summarize these statistics and compare this year’s thunderstorm season to the last couple seasons. In case you are curious, a brief explanation of how I gathered these statistics can be obtained by following this link.

Thunderstorm Days

The number of days with thunderstorms across southern Manitoba broken down into 6 regions. Includes the date of first thunderstorms and last thunderstorms.
The number of days with thunderstorms across southern Manitoba broken down into 6 regions. Includes the date of first thunderstorms and last thunderstorms.

In total, there were 94 thunderstorm days across southern Manitoba in 2014 (southern Manitoba being defined as the area shaded in the map above). This was slightly higher than in 2013 (89 thunderstorm days) but still much lower than in 2012 (~ 109 thunderstorm days). This is mainly the result of a late spring and thus, a late start to the season in both 2013 and 2014. 2012 featured an early spring with numerous thunderstorm events in March and April. This year, no thunderstorms occurred in March and only 2 thunderstorm days occurred in April. In fact, southeastern, eastern and Interlake portions of southern Manitoba did not see their first thunderstorm until the third or fourth week of May, at least a month later than usual. Winnipeg didn’t get its first thunderstorm until May 20, the 8th latest first thunderstorm on record since 1953.

The distribution of thunderstorm days, as seen in the map above, was fairly uniform across southern Manitoba overall. Similarly to 2012 and 2013, the region east of Lake Winnipeg saw notably less thunderstorm activity.

Interestingly, there was a thundersnow event in January! Although lightning detection products did not record the lightning, lightning was reported by residents west and southwest of Winnipeg on the evening of January 15; more specifically between Carman and Winkler. This was associated with a very strong cold front behind a potent Alberta Clipper. This clipper also brought record winds and high temperatures across the Prairies. Unfortunately, I could not find any data on winter thunderstorm activity in Manitoba historically. The only other occurrence of lightning in January I could find was a report in the Daily Free Press of lightning on January 16, 1876 (Penziwol, 2004). This is not to say that lightning has never occurred in January since then, but that is the only other report I could find. Nonetheless, this year’s thundersnow event was extremely rare for Manitoba.

In Winnipeg, 23 thunderstorm days occurred at the airport in 2014. Although this is the most since 2010, it is still below the normal of ~26–27 thunderstorm days. In fact, we have not had an above normal season since 2007. The last thunderstorm recorded was on September 8, tying for 10th earliest last thunderstorm since 1953. This puts the season at 112 days long, the 5th shortest on record. However, this statistic is a bit misleading. Thunderstorms did occur in southern parts of the city 3 times after September 8, including 2 events in October. I recorded 27 thunderstorm days here in South St Vital this year and the season lasted 156 days.

Severe Thunderstorm Warning Days

The number of days in which severe thunderstorm warnings were issued through 2014 in Manitoba, broken down by forecast region.
The number of days in which severe thunderstorm warnings were issued through 2014 in Manitoba, broken down by forecast region.

In total, there were 34 days with a severe thunderstorm warning issued in southern Manitoba. This is similar to 2012 but much less than in 2013 (45 severe thunderstorm warning days). The first warning was issued on May 24 and the last on September 8, putting the season at 108 days long. This is a tad less than in 2013 (110 days long) and 2012. As has been the case the last few years, southwestern Manitoba saw the most severe thunderstorm warning days in 2014.

Tornadoes

The number of days tornado warnings were issued across Manitoba in 2014, broken down by forecast region.
The number of days tornado warnings were issued across Manitoba in 2014, broken down by forecast region.

There were 4 tornado warning days in 2014, half the number in 2013 (8 days) but double the number in 2012 (2 days). The Red River Valley area saw the most. In fact, the warning zone southeast of Winnipeg, which Steinbach is situated in, saw 3 tornado warning days, the highest of all warning zones in Canada this year. However, only one of these warnings actually produced a confirmed tornado (an EF–0 southeast of La Salle on July 26).

From what I could find, 4 EF–0 tornadoes were confirmed in Manitoba this year. However, it is likely that there were more (many go unconfirmed). July 26 was the biggest tornado day of the year with 3 landspout tornadoes confirmed (all EF–0). 2 were in the Interlake near Waterhen and the other was southeast of La Salle.

A tornado might have touched down (unconfirmed) southwest of Winnipeg July 5. Part of the A Weather Moment team (Scott, Matt, Julien & Kyle) watched the storm as it evolved and managed to capture at least 2 funnel clouds. One of these is seen in Matt’s funnel cloud picture at the top of this post. After reporting this funnel to Environment Canada, a tornado warning was issued for the City of Winnipeg.

Monthly Frequency

Thunderstorm-related days per month (thunderstorms, severe thunderstorms and tornadoes) for Southern Manitoba in 2014.
Thunderstorm-related days per month (thunderstorms, severe thunderstorms and tornadoes) for Southern Manitoba in 2014.

For the first time since I started gathering these statistics in 2010, the busiest month of the year for thunderstorm activity across southern Manitoba was in June. The maximum is typically in July, but this year there was an unusual local minimum in activity in July with just 18 thunderstorm days. Residents in southwestern Manitoba were especially hard hit in June with multiple rounds of heavy thunderstorms and rains mid-late month. Over 150 mm of rain fell in the heaviest hit areas in just a period of 2 weeks. 251.6 mm of rain fell in June in Brandon, the rainiest June on record since 1890. 219.8mm of this fell in just the last 12 days of the month. Extensive overland and river flooding occurred as a result, as many of you likely still remember well.

If interested in comparing, follow these links for the 2013 and 2012 graphs: 2013, 2012.

Reference Cited
  1. Penziwol, Shelley. (2004). Storm Signals: A History of Weather In Manitoba. Great Plains Publications. Winnipeg, Manitoba. Page 3.

Mid-Week Warm-Up Gives Way to a Stormy Return to the Cold

Brad Leave a comment

Manitobans can enjoy slight relief from the bitter cold that has been in place the last few days as more seasonal temperatures are in place thanks to a fairly large low pressure system passing through Hudson Bay that has dragged the warm air all the way east from the Rocky Mountains. Unfortunately, the milder weather will be short lived as a series of cold fronts sweep southwards into the United States ushering the colder air back into the region.

Wednesday
-11°C / -17°C
Mixed skies with a slight chance of flurries
Thursday
-14°C / -17°C
Increasing cloud
Friday
-15°C / -19°C
Partly cloudy

Temperatures will climb to around –11°C today with mixed skies as a warm front slides through the region from the northwest. There will be a slight chance of flurries, particularly first thing in the morning and again in the evening into the overnight period, but otherwise it will be a seasonally nice day with westerly winds at 30–40km/h. Expect temperatures to drop to around –17°C tonight.

Thursday will be a bit of an in between day; a weak cold front passing through will bring daytime highs cooler than Wednesday – somewhere around –14°C or so – and a fairly sunny start to the day. By the afternoon, more cloud should begin working its way in from the west alongside the next low approaching from Saskatchewan. Little in the way of snow is expected here on Thursday or Thursday night and winds will be relatively light. Temperatures will dip back down to –17°C once again on Thursday night.

Friday will be the sunniest day of the second half of the week. A slight chance of some morning flurries will quickly clear out as we head to a high of around –15°C with light winds. However, a storm is brewing, and by Friday evening an Alberta clipper will be making its way into Southern Manitoba, set to pack a compact wallop as it moves through Friday night and Saturday.

End-of-Week Alberta Clipper Brings Winter Storm to Manitoba

An Alberta Clipper is forecast to track across Southern Manitoba Friday night into Saturday, bringing with it a significant shot of snow, strong winds, and then a plummet back into frigid Arctic air.

Note: Alberta clippers are compact systems whose impact depends significantly on their track. As we’re still several days out from this system, please take the following as just general guidance and remember that with a slight change in track, significant changes in the weather could be seen for any one location.

Snow will spread eastwards into southwestern Manitoba and the Parkland region on Friday evening, progressing across the remainder of the province through the evening hours. A relatively sharp deformation zone will set up across the Parkland & Interlake regions, limiting the northward extent of the snow. While many regions will see accumulating snow, the greatest amounts will be along the Trans-Canada corridor and the western escarpment of the Red River Valley.

First-guess snowfall amounts for the upcoming storm system this weekend.
First-guess snowfall amounts for the upcoming storm system this weekend.

By the time the snow stops on Saturday evening, around 10–15cm of snow may have fallen in a large swath encompassing much of the Trans-Canada corridor and areas south to the U.S. border. An area of higher snowfall will likely develop somewhere near the US border, perhaps just south into North Dakota, depending significantly on where & when the system pivots and begins heading E/NE instead of SE. In the core of heaviest snowfall, as much as 15–25cm of snowfall looks possible. Much of the Parkland and southern Interlake will see between 4–8cm, with amounts tapering off fairly quickly north of that.

In addition to the snow, this system will have fairly strong winds associated with it. Ahead of the low, easterly to northeasterly winds will strengthen to a gusty 30–40km/h. As the system passes through, winds will strengthen out of the northwest to around 50km/h with gusts as high as 70–75km/h. The strong northwesterly winds coupled with the ample fresh snow will likely produce blizzard conditions and make travel dangerous on Saturday. If you have travel plans, make a plan B in case this forecast happens to be right.

Temperatures will reach a high around –15°C on Saturday and then plummet to around –30°C on Saturday night with wind chill values near –45. Sunday looks clear and bitterly cold with a high of only around –26°C coupled with 20–30km/h winds that will produce wind chill values in the –35 to –40 range. If these wind chill values materalize, we’ll likely see extreme cold warnings issued for much of Southern Manitoba through the weekend.[1]

As mentioned, there is potentially significant variability to this forecast and what I’ve presented is the current most likely scenario. I’ll be keeping tabs on this system through the week and provide updates in the comments below and another full look at it in Friday morning’s blog post.

  1. If the extreme cold occurs while blizzard conditions are ongoing, the blizzard warning would “include” the extreme cold.  ↩

Winter Chill Settles Over Southern Manitoba

Brad Leave a comment

A strong Arctic ridge has brought the coldest weather so far this winter into the province. Temperatures will be well below seasonal[1] for much of the coming week.

Monday
-21°C / -31°C
Sunny

Tuesday
-23°C / ⇑ -18°C
Mainly sunny

Wednesday
-12°C / -22°C
Mixed to cloudy skies

Today’s post will be a relatively brief one since there simply isn’t much weather to talk about. Today and tomorrow will both be very cold days with highs not even hitting –20°C under mainly sunny skies. Tonight will bring lows dipping below the –30°C mark and winds at 10–15km/h creating wind chill values near or just below –40.[2] Tomorrow night will be quite a bit different, though, as an approaching low pressure system brings increasing cloud and climbing temperatures. By Wednesday morning, skies should be mixed to mainly cloudy with temperatures near –18°C. Through the remainder of Wednesday we should continue to see mixed to cloudy skies with temperatures climbing to around –12 or –11°C. There’s a slight chance for some flurry activity, but in general temperatures look a bit on the cool side for the kind of snow that would be possible. Skies clear on Wednesday night as temperatures drop into the –20 to –25°C range.

New Year, Same Story

Despite the promise of a new year beginning on Thursday, the story will be one we’ve heard before: a return to the deep freeze.

The NAEFS shows a high probabilty of below-normal temperatures next week.
The NAEFS shows a high probabilty of below-normal temperatures next week.

Another shot of bitterly cold Arctic air will begin working its way into the Prairies through the latter half of the week, with daytime highs dropping from the low minus teens into the –20 to –25°C range by the weekend. Overnight lows will follow suit, also dropping through the week and likely dipping below –30°C by the weekend. Little to no snow is expected. The exceptionally cold weather is expected to persist into next week.

  1. Seasonal daytime highs for this time of year in Winnipeg sit near –12°C  ↩
  2. –40 is Environment Canada’s threshold for extreme cold warnings, so we may see Southern Manitoba once again blanketed in warnings this afternoon.  ↩