Tag: Thunderstorms

Dry Spell to Break with Showers Tonight

Brad Leave a comment

The stretch of dry weather Winnipeg has been experiencing over the past month should come to an end tonight as a significant low crosses across the Central Prairies.


Analysis of 20:45Z Satellite Imagery for August 7, 2011

A system that brought all sorts of severe weather to Saskatchewan yesterday evening, including a potential tornado touchdown east of Regina, is pushing into Manitoba tonight and bringing with it the chance of severe weather for Southwestern Manitoba and much-needed rain to the Northern Red River Valley.

After battering residents of Saskatchewan from the Alberta border all the way to the southeast corner of the province, the main driving force for the entire system began to slowly move eastwards last night.  As it pushes through Saskatchewan, the favourable conditions that existed through much of Saskatchewan have been pushed eastwards to eastern SK and much of southwestern Manitoba.


Watches in effect for Manitoba at 4:50PM local time.

Weather watches are out for severe thunderstorms through much of southwest and Parkland Manitoba.  Thunderstorms will continue to develop into the evening and as the low pressure system and associated trough line move into the area, many have the potential to become severe with the main threats being large hail through Minnedosa and Dauphin, and the slight chance of a tornado in addition to heavy rains and large hail through southwest Manitoba.


6hr. QPF from the 12Z Aug 7 run of the GFS model valid for 09Z Aug 8 (~4AM local)

Winnipeg and the RRV will have a slight chance of some showers this evening (with the off chance of a lightning strike or two), however the extremely dry low-levels, with dew points only around 11°C, will make it unlikely that any cells that move into our area will actually be able produce rain that makes it to the surface.  However, by 9 or 10PM tonight, the low and trough begin to enter the RRV and a large area of rain with isolated embedded thunderstorms will develop, resulting in a large north-south band of rain that will pass over the RRV tonight.  Most areas will see 5-10mm of the wet stuff with a slight chance of 15-20mm in areas that see a thunderstorm tonight.  I think that the risk for severe weather will stay in the southwest portion of the province today; overnight we should just see rain and a slight chance of a light show.

Monday will be one of the most significantly different days we’ve had over the past month.  On the back side of this low, cooler air dives down from the northern Prairies.  Much of the Southern Prairies will see highs of only 18-22°C with brisk northwest winds gusting to 50km/h, which will make it feel downright cool relative to the last couple weeks.  Here in the Red River Valley, we also have a good chance of showers moving down from the interlake into the area by the early afternoon.

After our damp, windy, cool Monday, things improve through Tuesday and we’ll be back into the high 20’s by Wednesday.  More rain may be in store for the later half of the week, but more on that later.

I, for one, welcome a nice rainy night.  So does my lawn…

Rain and Thunderstorms for Next Week

Brad Leave a comment

The soggy spring we’re experiencing in Southern Manitoba just doesn’t seem to be letting up.  With some areas in Southeast Saskatchewan and Southwestern Manitoba already having seen in excess of 2/3s of what they normally receive through an entire year, everybody, including the ground, is ready for a break from the rain.  Unfortunately, it doesn’t look like it’s in the cards.  A sunny and warm weekend will change into quite an unsettled pattern for the first half of next week.  Read on to find out where and how much rain will fall.


24hr. QPF valid 12Z Monday morning from the 00Z Friday Jun 10 GEMGLB model.

Enjoy the sunshine and warmth today and tomorrow!  Plenty of sunshine is in store for us with daytime highs in the low twenties and fairly light winds.  Most of Sunday will be pleasant as well, but by evening a new system is going to be pushing into Southwest Manitoba.

An trowal will swing through Southern Manitoba Sunday night through Monday, bringing with it another batch of rain and thunderstorms.  By Sunday evening, rain will begin to push into Southwest Manitoba with a chance of thunderstorms developing before midnight.  While much concern exists about the more rainfall for SW Manitoba, it looks currently like the greatest threat for heavy rain exists from areas south of Winnipeg and spreading eastward through the Whiteshell.

As the trowal rotates into our area on Sunday, an area of thunderstorms should rapidly develop on Sunday evening in North Dakota near and east of the triple point of the associated wave.  For those who don’t know what that is, the triple point is the point where the warm front and the cold front meet.  This should develop upscale quite rapidly into a large MCS that will track east northeast and should cross into S. MB overnight.  Currently, it appears that Winnipeg would be on the northern edge of the higher amounts, with it likely that areas south of the city could see 20-40mm of rain.  Areas elsewhere in Southern Manitoba (including the Southwest corner) that are not impacted by the MCS from North Dakota will see between 10 and 20mm of rain through Monday evening.

This system will then pull northward and rotate into Central Manitoba.  Unfortunately, this prolonged period of rain could bring an additional 20-30mm to the absolutely soaked Interlake region, which is battling un-before-seen high lake levels.

Perhaps of even bigger concern is the next system that will barrel into Southern Manitoba on Wednesday evening.  While details are sure to change, this has the potential to be the most significant convective system we’ve experienced this year.  An extremely intense shortwave will head northeast into North Dakota through the day on Wednesday and initiate a large area of convection by Wednesday evening.  This convection will be pulled northward with the shortwave as it slowly becomes captured in an upper low and rests over the western lakes.  


12hr QPF valid 12Z Wednesday morning, June 15 from the 00Z Friday June 10 GEMGLB.

Thunderstorms will develop and intensify through an upper trough and pull northward into the upper low, resulting in prolonged, intense precipitation along a fairly narrow band.  Positioning will be crucial for this system, but with the potential to be dumping 1.5” – 3” of rain through the RRV into the Interlake, this will be a extremely important system to keep an eye on.

So get out and enjoy the sun!  As summer tries to push in next week, the storm track is going to move back into Southern Manitoba and we are likely going to see several impulses move through during the week.

Significant Storm System Heading into Manitoba

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A powerful early-summer storm system has pushed through Montana overnight and pushed into Southwestern Manitoba, bringing with it heavy rain and widespread thunderstorms.  Read on to find out what’s in store for today, and where there might be severe thunderstorms…


0845Z 10.7u/3.9u Multispectral Satellite Imagery; a extremely large area of thunderstorms covers most of Southern Saskatchewan, the northern half of Montana.  This system also has an arm of convection that extends west-east across northern North Dakota approaching the international border.  This system has brought nickel sized hail to the Estevan region and 90km/h wind gusts to northern Montana.

A significant storm system ejecting from the Rocky Mountains intensified rapidly overnight and has produced widespread thunderstorms throughout southern Saskatchewan.  This system will move eastwards through the day today, pushing precipitation through Manitoba.

The setup today is quite complex.  There is a surface low running near the international border that is connected to the upper-level impulse.  These two features are acting in tandem to produce much of the convection in Saskatchewan this morning.  Further to the southeast, a surface low is entering into western North Dakota with an associated frontal wave attached to it.  A warm front extends through southern North Dakota and across central Minnesota, with a cold front laying south from the low pressure centre along the Montana/Wyoming – Dakotas boundaries.


1000Z Radar Composite for the Prairies

So!  For Southern Manitoba today.  The band of thunderstorms stretching from Melita-Virden to Emerson should continue through the early morning hours, but will be sheared apart by mid-to-late morning as the western portion of the line is pulled westward around the upper low and the eastern half is pushed further east by a significant low-level jet.  I think that there will be thunderstorms up to a line that lay from Portage la Prairie – Winnipeg – Kenora.  North of that line (including Portage and Winnipeg), I’d say that there’s a good chance of some showers this morning, but only a slight risk of a thunderstorm as the line is weakened through the stretching as well as the morning sun.

After that line passes, we’ll see a relatively cloudy lunch and early afternoon.  During this period, the warm front in North Dakota will have advected northward and lay fairly close to the Canadian border.  By mid-afternoon, convection will initiate south of the border along the warm front, caused by daytime heating and increasing instability as the upper centre approaches.  These storms will probably become marginally severe to severe quite quickly, with the main threat being large hail.  There is a slight chance that storms right near the warm front could produce tornadoes.

I think that the worst should stay south of the border, but it’s highly dependant on how far north the warm front can push.  The SPC agrees with me, and has pushed their slight risk area into Southern Manitoba, with concerns that the worst could actually occur on our side of the border.  I’d advise anyone living within 75km of the border in the Red River Valley and east to keep an eye out for weather watches or warnings this afternoon.


24hr. precipitation accumulation valid 12Z Wednesday morning from the 00Z June 7 GEMREG model.

Storms that initiate along the warm front should become elevated this evening, as they become support by a strong low level jet overrunning the warm front.  As the upper low moves across Southern Manitoba, it too should support an area of convection due to significant instability aloft.  All this will move through overnight, giving rain and thunderstorms to many areas in Southern Manitoba.  Rainfall amounts may vary significantly depending on convection, but general widespread amounts will likely be from 15-25mm, with areas that get battered by thunderstorms potentially seeing 30-40mm.

We should see some light rain tomorrow morning through the RRV and points east as the system pulls out, with skies beginning to clear through the afternoon.  After that, it looks like we’ll have at least a few days without rain before the next system moves through!

Just enough time to mow the grass.

Brad Leave a comment

Enjoy the sun today and tomorrow because guess what, more rain is on the way.


June 3, 2011 Hand-Analysis of 12Z Sounding Data; Black lines are heights, coloured lines are θw values.

The broken record keeps on repeating in Winnipeg as rain gives way to sun gives way to rain with just enough time to mow the grass in between.  With the system that brought numerous damaging storms across Southern Manitoba yesterday moving out, the upper flow aligns itself to place the Southern Prairies directly along the main storm track.


Convective outlook for June 3, 2011.

Little significant weather is expected in Southern Manitoba today, with only the slight chance of a thundershower or two over the Parkland areas, mainly in the northern Minnedosa and Dauphin regions.  Sunny skies will prevail through the evening for areas in the Red River Valley and east before a few clouds move in overnight.  Get out there and enjoy the beautiful weather!


24hr. cumulative precipitation valid 12Z Sunday 5 June from the 12Z 3 June GEMREG; my personal opinion is that it drags the precipitation a little too far south across the Prairies and that the streak through Southern Manitoba will likely be further north.

Things change by tomorrow evening, though.  A new system currently moving into the Prairies from the Yukon Territory will arrive in the Southern Prairies by tomorrow afternoon and into the Red River Valley by tomorrow evening.  This system will produce a lengthy trail of precipitation, however it’s north-to-south width looks fairly narrow.  The exact position of this shortwave will determine where precisely the rain will fall, although all indications currently point to another 2-4mm of rain pushing through the Winnipeg/Gimli/Selkirk/Whiteshell areas with lesser amounts further south.

This precipitation looks to clear out by Monday morning, leaving behind general instability through the region due to an elongated surface trough hanging back from the main system.

The sun will then come out (hopefully) in full force Monday afternoon and Tuesday morning, before cloud moves back in on Tuesday afternoon ahead of yet another low pressure system.


12hr. cumulative precipitation valid 12Z Wed 8 June from the 12Z Fri 3 June GEM-GLB

This third system within a week will push in on Tuesday evening with a warm front positioned just south of the international border, draped west-to-east across North Daktoa.  Some light rain with the risk of elevated thunderstorms riding over the warm front with push into our area by Tuesday evening before developing into a large area of moderate rain overnight.  It looks to rain through Wednesday and most of Thursday night before tapering off on Thursday morning.

This system is still a ways off, so we’ll fire off another blog post in a couple days with some more details on that one.  We’ll update Sunday’s system right in the comments here.

Do you have any stories or pictures from the storms yesterday?  Feel free to leave them in the comments or fire a tweet off to our official Twitter account, @WeatherInThePeg.