Tag: Thunderstorms

Saskatchewan Severe Storm Outbreak; Quiet in the Red River Valley

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We’ll move into a slightly quieter pattern after a low pressure disturbance moves through central Manitoba. This system is currently moving through western Saskatchewan and will produce a dangerous outbreak of severe thunderstorms along the Highway 11 corridor between Saskatoon and Regina today with torrential rain, hail possibly bigger than baseballs and a very real threat for an isolated tornado or two. The severe weather threat will be mostly confined to Saskatchewan today unlike Saturday when the substantial severe storm threat was expected to push into SW Manitoba.

Today & Tonight

Monday

30°C
Clearing then mainly sunny.
Monday Night

20°C
Cloudy periods with a chance of showers.

We’ll see a beautiful day toaday in the Red River Valley with sunny skies dominating after a few isolated showers move out of the area this morning. We’ll see temperatures climb to around 30°C this afternoon before some clouds move in in the evening ahead of the storms moving out of Saskatchewan. There will be a slight chance of showers tonight through the Red River Valley along the tail end of a thunderstorm complex that will be moving through the Interlake. As the low pushes across central Manitoba, the Red River Valley will move into the warm sector of this system, bringing much warmer, more humid air into the region. Thanks to this, we’ll see overnight lows quite a bit warmer than the past couple nights. We’ll eventually drop to around 20°C with noticable humidity.

Severe thunderstorms will move into western Manitoba this evening along a dryline pushing eastwards out of Saskatchewan. Storms are expected to stay well north of the Trans-Canada Highway, moving more through the Dauphin & Minnedosa areas then pushing eastwards into the Interlake overnight as an MCS capable of producing large hail and strong damaging winds. The storms will have trouble moving southwards thanks to a layer of dry air in place over the Red River Valley that will likely either kill or substantially weaken any weather that tries to push our way.

Tuesday & Wednesday

Tuesday

27°C / 15°C
Clearing then mainly sunny.
Wednesday

27°C / 15°C
Sunny with cloudy periods.

We’ll see more stable weather for Tuesday & Wednesday as a surface ridge begins working it’s way into the province. A fairly light northwesterly wind will kick in on Tuesday morning which will slowly push out much of the humidity in place over us making this feel quite a bit more comfortable outside. Wednesday will bring more sun than cloud with daytime highs pretty much the same as Tuesday. There will be a slight chance of light showers near the International Border through the period but no significant accumulations are expected.

Severe Thunderstorms Ravage Saskatchewan and Manitoba

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A line of severe thunderstorms tore across southeastern Saskatchewan and southwestern Manitoba yesterday producing widespread damage due to rain, hail, and what is increasingly likely a tornado.

A verification of the AWM Severe Thunderstorm Outlook issued on Saturday morning. Green dots: Severe Hail Reports. Blue dots: severe wind reports. Red dots: tornado reports.

A potent severe weather setup was in place yesterday as a trough of low pressure began to move it’s way from Alberta into the hot, humid air that was pushing into SE Saskatchewan. Ample moisture, heat, instability and wind shear was in place for the development of severe thunderstorms and – given the strongly veering wind profile – the likely development of tornadic supercells. With this in mind, we issued our morning severe weather outlook with a moderate risk for severe thunderstorms in the Estevan, Carlyle, Moosomin, Virden & Melita forecast regions, with a slight risk extending further eastwards into the Pilot Mound & Brandon regions.

Saskatchewan Pounded By Large Hail

Supercell thunderstorm developing just SW of Weyburn, SK at 1900Z.

Supercell thunderstorm developing just SW of Weyburn, SK at 1900Z.

Storms developed earlier than expected; by 1900Z there was a supercell taking shape not too far SW of Weyburn, SK. This supercell ended up being the storm of the day, lasting over 8.5 hours before finally dying near the U.S. border near Gretna, MB. A line of storms quickly developed extending from the main supercell SW into Montana. It rapidly developed into a line of 5 or 6 supercells that all began rotating quickly and producing torrential rain and extremely large hail. Environment Canada had issued a tornado watch for the region around 9:30AM local time which mentioned the threat for supercell thunderstorms capable of producing torrential rain and large hail in addition to the threat for tornadoes.

The reports began flooding in on #SKstorm as the severe storms began impacting larger communities. Environment Canada issued a timeline of reports it received that went like this:

Location Time (Local) Report
Weyburn 1:49 PM Quarter size hail
Hume 2:00 PM Loonie hail
Weyburn (8 km W) 2:21 PM Golf ball hail
Arcola 2:43 PM Funnel cloud
Kisbey 2:45 PM Quarter size hail
Weyburn (5 km W) 2:55 PM Golf ball hail
13 km SE Weyburn 3:00 PM Grapefruit size hail
16 km SE Weyburn 3:00 PM Golf ball hail
Minton (13 km S) 3:15 PM Possible brief tornado
Forget 3:20 PM Golf ball hail
Lampman 4:19 PM 50 mm rain, 80 km/h gust
Redvers 4:29 PM Toonie size hail
Oxbow (8 km N) 4:45 PM 50 mm rain in 15 minutes

Photos that began coming in on Twitter were pretty incredible. Tight lowerings on storms were showing that they were spinning quite intensely and numerous funnel clouds were spotted. But int the end, the big story in SE Saskatchewan was the rain and hail.

Large hail near Weyburn, SK

A photo of large hail near Weyburn, SK. Credit: Craig Hilts

There were numerous reports of tennis ball sized hail upwards to one report of grapefruit sized hail (a grapefruit is around 9cm wide). The hail produced by these storms produced significant damage to crops in the region as well as to personal property, with many reports of car windshields being broken by the hail and images showing up on Twitter of house windows being smashed.

Photo of flooding in Bienfait, SK

Picture of flash flooding in Bienfait, SK. Credit: SK storm chaser @NickTheBody.

Flooding was also a problem in numerous places as the storms dumped unbelievable amounts of rain. At some points, rainfall rates exceeded 200–225mm/h as torrential rain brought zero-visibility conditions. @NickTheBody caught the snap above of the flash flooding that occurred in Bienfait, SK after a thunderstorm rolled through.

Doppler RADAR showing strong couplet near Carlyle, SK

Doppler RADAR showing a very strong couplet as as supercell thunderstorm bears down on Carlyle.

As the storms pushed further east, however, they began to take on some very ominous characteristics. As the storms pushed deeper into the moist, warm air the winds at the surface began to back a little bit more; further west surface winds were mostly out of the south, but as they moved towards the Manitoba border the surface winds became more and more southeasterly. Very quickly strong rotation began to show up on RADAR, with the main supercell we’ve been tracking showing a very intense velocity couplet as it moved towards Carlyle, SK. The storms had always shown rotation since nearly the beginning of their lifespan and had the capability to produce tornadoes at any time, but it was at this point these storms began to look like they could produce a large, long-lived tornado. The storm about to hit Carlyle, in particular, was becoming the storm to watch.

Supercell Tears Across Southwest Manitoba

And watching it we were! Matt, A Weather Moment contributor and @lovestormsMB was out chasing and had been on the storm for hours at this point. While hopes of seeing anything rapidly diminished as the storm became what is known as a HP supercell[1], he was able to feed important information via his Twitter account.

Supercell thunderstorm over SE SK / SW MB

HP Supercell just SW of Carlyle, SK on Saturday evening as the storm approached the Manitoba border. Credit: @lovestormsMB

This storm – for lack of any better terminology – looked vicious as it moved into Manitoba. It was tracking along Highway 13 and moved straight towards Reston – a town that has already had to deal with multiple severe storms this year already – and Pipestone, a town somewhat famous for the Pipestone tornado.

Unfortunately, it didn’t take long for word to come that there was certainly significant damage occurring under that storm. Environment Canada also issued a timeline for reports it received on the Manitoba side:

Location Time (Local) Report
Sinclair (7 km N) 6:00 PM Ping pong size hail, severe winds with trees down
Reston 6:49 PM Nickel hail, 42 mm rain
Pipestone 7:00 PM Tornado, significant damage
Pipestone (20 km E) 7:30 PM Tornado, golf ball hail
Hartney 8:00 PM Possible tornado

Dramatic photos began coming in from the Pipestone region as well:

HP Supercell Approaching Pipestone

Photo of the HP supercell near Reston, approaching Pipestone, MB. Credit: @lovestormsMB

Downed tree in Pipestone

Photo of a large tree snapped in half in Pipestone. Credit: Tim Smith / Brandon Sun

Mobile home thrown into the rink in Pipestone

Photo of a mobile home thrown into the rink in Pipestone. Credit: @Snipe_All_Day

Destroyed cattle shed in Hartney, MB

A destroyed cattle shed in Hartney, MB. Credit: @LD_StVital

The clean-up continues today in Pipestone and Hartney while damage continues to be assessed in southeastern Saskatchewan. Unfortunately for those in Saskatchewan there will be little time to recover as another potent setup for a severe storm outbreak will be in place Monday afternoon bringing, once again, a tornado, torrential rain and large hail risk. Regions in SW Manitoba should be a little safer this time. We’ll have the full details of that in tomorrow’s blog post.

  1. The “HP” in “HP supercell stands for ”high precipitation.” HP supercells often have obvious, dramatic structure form afar, but little of the internal workings are visible due to the copious amounts of precipitation falling out from them. HP supercells are extremely dangerous storms as any tornadoes they produce are often hidden from sight behind all the rain.  ↩

Active Pattern Developing

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A more active pattern will be setting up over Southern Manitoba as a southwesterly flow aloft develops thanks to a quasi-stationary high pressure system that will set up shop over eastern North America. This will bring us multiple chances of rain and thunderstorms over the next 5 days or so.

Friday

28°C / 16°C
Showers or thunderstorms ending in the morning, then a mix of sun and clouds with the slight chance of a thunderstorm.
Saturday


30°C / 16°C
More sun than cloud. Increasing cloud then risk of showers or thunderstorms overnight.

Sunday

28°C / 16°C
Mainly sunny. Might actually not rain.

Friday

We’ll see a rainy start to the day as the remnants of Thursday night’s nocturnal convection begin to dissipate over the Red River Valley. Showers or thunderstorms will taper off through the morning, leaving us with a mix of sun and cloud by midday. Thunderstorms will redevelop along the main surface trough in Southern Manitoba in the afternoon but the complicating factor will be the positioning of the trough, which is extremely uncertain at this point.

Forecast location of the surface trough at 1PM CST from the RDPS.

Forecast location of the surface trough at 1PM CST from the RDPS.

It seems most likely that the trough will be east of Winnipeg by the time things redevelop along it, although due to that uncertainty we’re keeping a slight chance of another thunderstorm through the early afternoon in for Winnipeg. We’ll update in the comments below if it’s readily apparent that the trough will be east of town by mid-morning. We’ll see clearing skies tonight as we head to a low of around 16°C.

The Weekend

Saturday will be a hot day with relatively comfortable humidity. We’ll see temperatures climb to around the 30°C mark again across the Red River Valley under a mix of sun and cloud – although there should be more sun out there than cloud. We’ll see some increasing cloudiness in the evening as a weak upper trough pushes into the province. There will be a chance of showers or thunderstorms through the overnight period for a large swath of Southern Manitoba, although at this point the best chance looks to be from Dauphin to Brandon and then in the Red River Valley near the western escarpment.

Sunday will be a nice day where we might actually have no chance of rain! Temperatures will climb back into the high 20’s – probably close to 28°C again – under mainly sunny skies. Sunday night will be clear with a low near 16°C.

Next Week

At this point, Monday and Tuesday both look like relatively rainy, possibly stormy, days as a train of disturbances move over Southern Manitoba. There are hints that once we get past the first couple days, we’ll return to a more stable pattern, but first thing’s first; we’ll continue to have updated thoughts and details in the comments below!

Hot Weather Building In; Severe Storms to End Week?

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Hot, increasingly humid weather will begin working it’s way back into Southern Manitoba as a southerly flow at the surface, advecting moisture northwards from the US Plains, combines with an upper ridge over the Prairies that will work to crank up the heat.

Model winds at 500mb showing the strong upper-level ridge forecast over the Prairies on Thursday.

Model winds at 500mb showing the strong upper-level ridge forecast over the Prairies on Thursday.

Today

Wednesday

28°C / 15°C
Sunny.

We’ll see a pleasant day today with sunshine dominating the skies and a light northwesterly wind. Temperatures should climb up to around 27°C while the northerly winds keep the humidity down making it a very comfortable summer day. Skies will remain clear overnight as we drop to a low of around 15°C. There will be a very slight chance of a thundershower or two in the Red River Valley through the afternoon hours, but if they do develop they’ll most likely be tied to areas along the western escarpment and northwards towards Riding Mountain park. There would be a very marginal chance of any of these storms becoming severe; if any were to the main threats would be heavy rain and large hail.

Thursday & Friday

Thursday

30°C / 19°C
Sunny & increasingly humid.

The heat will build a little more on Thursday, but the real big difference will be the humidity which will become very noticeable as the winds shift around to the south on Wednesday night and allow the dew point to start climbing. They should reach the mid-to-high teens by Thursday evening which, when combined with our expected daytime high of 30°C will make it feel more like the mid-to-high 30’s. No storms are expected as a strong cap keeps everything in line.

Friday

28°C / 14°C
A mix of sun and cloud; showers or thunderstorms with passage of cold front. Very humid until front passes.

Friday will be the most active day of the week as ample heat and humidity are in place ahead of a moderately strong cold front that will work across Southern Manitoba through the day. It looks likely that storms will initiate on the front fairly early in the day (perhaps even by late morning if nocturnal storms don’t just march out of North Dakota and continue through the day) and pose the risk of becoming severe as they will have ample energy available to them.

High CAPEs combined with ample bulk shear (0–500mb bulk shear values are expected to be in the range of 50–60kt) will allow storms to organize quickly and introduce the threat for large hail and strong winds. Shear values are generally running parallel to the front, which means slow frontal motion could produce training thunderstorms that may produce localized flash flooding. The threat for tornadoes looks fairly low given that winds right near the surface may not be able to move into a favourable direction due to the orientation of the front and tilt of the entire system. While tornadoes can never be ruled out of severe thunderstorms, at this time it doesn’t look like the threat should be considered one of the primary threats for Friday.

The day may be more cloud than sun depending on how convection develops to our south and west on Thursday night, but we should see a high temperatures anywhere from 25°C to 28°C before the front comes through. The passage of the front will bring northerly winds which will flush out a lot of the humidity that will have built up over the prior days which should make things quite a bit more comfortable. Things will clear out overnight as we drop to a low in the mid-teens.

The Weekend

Looking ahead to the weekend, we’ll see plenty of sunshine return with highs climbing in the 27–30°C range with comfortable humidity. It looks great. Keep tuned here and to our team on Twitter (@WeatherInThePeg, @steinbachwx and @lovestormsMB) for updates and thoughts on Friday’s severe weather potential. Until then, enjoy summer!