Category: Forecasts

Significant Storm System Heading into Manitoba

Brad Leave a comment

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.

Showers and Thunderstorms, U2, Then More Rain

Brad Leave a comment

While the temperatures may not be completely summer-like, today will be a day that indicates a clear shift towards summer weather.  An incoming disturbance will produce widespread convection today with showers and thundershowers covering much of Southern Manitoba.  Pleasant weather should make an appearance for tomorrow’s U2 concert, but Winnipeg will quickly return to rainy weather on Monday as a system that will bring significant challenges to those with housing near the lake moves into the province.

A substantial stacked low pressure system currently positioned just east of Regina is set to move across Southern Manitoba today.  A few factors will combine to produce what could be a fairly interesting afternoon today.  

First, a southerly wind, combined with yesterday’s rain has pushed dewpoints to nearly 10°C throughout the Red River Valley with a relatively deep layer of evidenced by the stratus cloud that has managed to form overnight despite winds of 15-20km/h.  This moisture will provide the fuel needed for thundershowers. 

Secondly, rather cool mid-level temperatures will be in place.  As the low pushes in, temperatures in the mid-levels should drop to -7 to -8°C, which when combined with daytime heating will produce ample instability to get convection initiating.  It is also indicative of fairly low freezing level, which will help in the generation of small hail.

And last but by far not least, the fact that this upper disturbance is stacked on top of a surface low means that there will be significant rotation through the mid and upper levels which will help storms develop rotation.

When these things combine, it’s considered a pretty classic case for cold core funnels.  These funnel clouds do not develop in the classic sense; instead of developing in the rapidly rotating updraft of supercell thunderstorms, they develop through the descent of cold air through a storm that has developed rotation due to significant mid-to-high level spin.  Think of it as a funnel cloud that develops because of how air is coming out of the cloud rather than how air is being ingested into the cloud.

These funnel clouds do have the potential to touch down and become tornadoes.  If they do, they are often extremely short lived (< 1-2 minutes) and are much weaker than the tornadoes that form from supercell thunderstorms.  Any of the storms that could produce a cold core funnel cloud are also extremely likely to be capable of producing hail.

I think that most areas across Southern Manitoba could see hail today, although the threat is biggest in the Red River Valley and east.  Winnipeg and areas south should most likely see pea-sized hail should it develop.  Further east in the Whiteshell and Sprague regions, the potential exists for marginally severe hail (about dime to quarter-sized).

The biggest hindrance to the development of all this is the lack of focus for convection.  With no strong front or trough, convection may simply blow up all over the place instead of in any organized fashion, which will leave all the storms fighting each other for resources.  If this happens, it’s likely that it would quickly blossom into a big area of showers with only the odd lightning strike.

My bet for the Red River Valley is this: low stratus this morning will burn off quickly with the morning sun.  By mid-morning, most areas should be seeing a mix of sun and cloud.  Daytime heating, combined with a weak cap, will initiate the convection earlier than typical, resulting in showers spreading into the Red River Valley around 12-1PM or shortly thereafter.  Any showers that develop in the RRV are just as likely to become thundershowers, and I think there will be numerous funnel clouds today.

As for Sunday and the big U2 concert, it should be quite a pleasant day.  We’ll see a sunny morning give way to a mix of sun and clouds in the afternoon with a daytime highs around 15-17°C.  It will cool off quick in the evening, so make sure to bring a sweater if you’re headed to the concert.


12hr. QPF valid 06Z May 31 from the 06Z May 28 GFS

After that, it looks like a significant low pressure system will track through Southern Manitoba, bringing nothing but headaches and grief for residents on the lakes.  Current indications are for a widespread area receiving 20-40mm of rain with winds potentially as high as 50 gusting to 70 km/h.  This system will do no good for the flood-striken areas near the lakes, and I would suggest that residents in the area should begin to make preparations already as with the strong winds out of the north-east, significant water damming will likely occur on the western to southern beaches.

Deadly Storms Hammer Oklahoma, More Expected Today

Brad Leave a comment

I know this isn’t directly related to Southern Manitoba, but the events over the past few days have been so significant I can’t pass up the opportunity to talk about them.  On Sunday, a massive tornado that was recently upgraded to the category EF5 tore through Joplin, MO, killing 125 people and injuring upwards of 750 people.  Over 1500 have been reported missing, however this number is likely inflated as they are preliminary reports mostly from family and some “missing” peoples were simply out of town.  The tornado damaged or destroyed over 800 structures and caused in excess of $1 billion.

Damage Path of the Joplin Tornado
The swath of damage caused by the tornado is easily visible from the sky.

Many thought that this disaster would not be seen for a long time, however mother nature had a completely different opinion yesterday and many, though not all, Kansas, Oklahoma and Texas residents dodged quite a few bullets yesterday.

 Around 3PM yesterday storms started to develop along a dryline pushing eastwards out of Colorado and New Mexico into the Central Plains.  This feature was extremely strong, with some sites going from 29/23 (temperature / dewpoint) to 38/-12 in a matter of a couple hours.  This would be equivalent to going from one of the muggier, more humid days in Southern Manitoba to the Nevada desert over lunchtime.  Normally, this would be a significant enough feature in itself, but there was also a powerful shortwave moving into the area with an associated 90 knot jet streak about 5km off the ground.  This was, for all intents and purposes, a perfect setup for severe storms.

The Storm Prediction Center (SPC) issued a high risk for for the Central Plains yesterday morning, and issued a PDS statement (Particularly Dangerous Situation) near lunchtime when they issued the tornado watch.   By mid-afternoon storms were in full swing.  The northern end of the town of El Reno, OK was hit by a tornado, which killed two people, demolished several houses, and was responsible for a gas explosion.  This picture is a great indicator of how powerful this twister was:

 
A car pinned against trees that have been significantly de-barked in El Reno, OK.

There was even a weather station on the north end of town that experienced a significant portion of the power of this tornado:

 
Readings from a weather station in North El Reno.  At the time of the tornado, the station measured a peak wind of 151 m.p.h and a drop in pressure to almost 940mb.

El Reno was not the only town to suffer, though.  The town of Piedmont, OK was hit hard:

 
(Photo: Reuters / Bill Waugh)

Dozens of homes and businesses were lost in Piedmont.  Two children were killed, a third missing, and their mother is in critical condition.  This repeats itself, unfortunately.  Oklahoma City was put under a tornado warning only for the tornado to dissipate shortly before entering the city.  Instead, debris rained down on the city, enough to make the I40 impassable in at least one spot.  The Norman, OK weather center, home of the SPC was evacuated.  Baseball-sized hail fell at the baseball stadium in Arlington, TX as well as through much of Fort Worth.  More details have yet to emerge, but it sounds as if the town of Denning, AR may have been wiped off the map by a tornado.

It was a tragic day through much of the Central Plains.  The current death toll of 15 is likely to rise as the damage is assessed today and people start to examine and clean up.  At least 4 significant tornadoes occurred yesterday, and several were on the ground through the night.  It was another unfortunate and deadly day in a country that is quickly approaching its deadliest year ever with respect to tornadoes.  And it isn’t over yet.  The SPC has issued another high risk outlook for portions of Arkansas, Tennessee, Indiana, Kentucky, Illinois, and Missouri, with a moderate risk encompassing a much greater area:

It’s an extremely unfortunate year for tornadoes, and at this point it’s hard to imagine that they won’t surpass their deadliest year ever for tornadoes this summer.  If there’s any good that might come out of this, it only emphasizes the importance of having a properly funded forecasting service that is working around the clock to ensure that people and property can be protected as much and realistically as possible.  Good thing those budget cuts to the NWS didn’t go through…

The last thing I wanted to mention, perhaps my whole reason for writing this, is that I know many people who think that these sorts of things “don’t happen in Canada.”  I’m here to say that they do.  More often than one might think.  Tornado alley, a colloquialism used to refer most frequently to the stretch from Oklahoma to South Dakota, actually extends much further than most people think it does.  While tornadoes may be most frequent in those states, it slowly shifts north as summer goes on.  The Dakotas and Minnesota are hotspots for tornadoes.  By mid-to-late summer, tornado alley extends through Southern Manitoba and arcs westwards across Saskatchewan and into Alberta.  One need not look far to see extremely significant tornadoes in Canada’s history:

  • Reeces Corners Tornado (1983); millions of dollars in damages.
  • Southwest Ontario Tornado Outbreak of 1984; 6 confirmed tornadoes, 30 people injured.
  • The “Barrie” Tornado Outbreak of 1985; 13 touchdowns including a F4 tornado in Barrie, ON.  12 killed, 100 injured.  Over 100 buildings destroyed at a cost of over $100 million.  Complete destruction of 300 houses.
  • Mississauga Tornado (July 7, 1985); Injures 10, $400,000 in damages.
  • Saskatoon Tornado (June 1, 1985); 3 weak tornadoes touched down in Saskatoon.  Roofs and windows damaged.
  • “Black Friday” Tornado in Edmonton, AB (July 31, 1987); a strong F4 tornado (possibly F5) hit eastern sections of Edmonton.  27 people died and 253 were injured.  One of Canada’s strongest tornadoes.
  • Medicine Hat, AB Tornado (1988); Tornado caused estimated $50 million in damages.
  • Saskatchewan Outbreak of 1989 (June 19, 1989); 8 tornadoes touch down over central Saskatchewan.
  • Edmonton Tornado (July 27, 1989); Weak tornado in the west end of Edmonton.  2 people injured.  Buildings damaged, trees and power lines uprooted.
  • Mont-Saint-Hilaire tornado (November 16, 1989); An F2 tornado caused $2 million in damage in the community east of Montreal.
  • Sarnia, ON (March 27, 1991); Early season tornado causes an estimated $25 million in damages.
  • Southern Manitoba (June 24, 1992); 5 confirmed tornadoes as well as hail up to the size of tennis balls.
  • Saint-Charles, QC (July 9, 1994); 1 person was killed when a F2 tornado tore through the town.  3 others injured and about 12 homes were damaged.
  • Aylmer, QC Tornado (August 4, 1994); A F3 tornado injures 15 people in Aylmer, QC.  Tornado path was 8km long and caused major damage to a downtown residential subdivision.
  • Turtle Mountain, MB (August 27, 1994); An F4 tornado hits rural farmland with devastation evident at Mayfair Hutterite Colony.  Well over $1 million in damages.
  • Southern Ontario Tornadoes of 1996 (April 20, 1996); Two F3 tornadoes touch down in Grey County, Wellington County and Dufferein County.  Significant property damage, 9 injuries.
  • Saskatchewan (July 4, 1996); 9 tornadoes touch down in the Saskatoon, Maymont and Osler areas in Saskatchewan.  An F3 was measured in the Maymont area.  Homes and property were damaged in Osler.
  • Hull, QC of 1999 (May 8, 1999); A tornado over Hull, QC caused $2 million in damages.
  • Saskatoon Tornadoes of 1999 (May 18, 1999); 3 tornadoes touch down close to the western limits of Saskatoon, SK.
  • Pine Lake, AB Tornado (July 14, 2000); An F3 tornado rips through the Pine Lake campground.  12 people killed.
  • Guelph, ON Tornado (July 17, 2000); An F2 tornado struck the city of Guelph, ON causing around $2 million in damages.
  • Wabamun, AB (August 13, 2003); A tornado touched down on a golf course and lake resort west of Edmonton, AB causing some injuries.
  • May 2004 Tornado Outbreak (May 22, 2004); one strong F2 struck near Mitchell, ON and an F3 in nearby Gad’s Hill.  Extensive property and infrastructure damage.
  • Nipawin (May 23, 2005); A tornado touches down in and around Nipawin, SK.
  • Southern Ontario Tornado Outbreak of 2005 (2005); Widespread damage path from Stratford, ON to Peterborough, ON and along Georgian Bay near Collingwood.  Damages exceeded $500 million.
  • Ontario Outbreak of 2006 (August 2, 2006); 14 confirmed tornadoes rip across southern ontario.
  • Gull Lake Tornado (August 5, 2006); One woman is killed at the Gull Lake campground north of Winnipeg, MB.
  • Eastern Prairie Outbreak of 2007 (June 22-23, 2007); At least 8 tornadoes across southeast SK and southern MB.  The first confirmed F5 tornado in Canada occured at Elie, MB, just west of Winnipeg.  It destroyed 4 homes and heavily damaged a flour mill.  The tornado itself was described as “as bad as they get here in Canada.”  A F3 wedge tornado also touched down near Pipestone, MB and Baldur, MB.
  • Southern Manitoba (May 25, 2008); at least two tornadoes touch down in Southern MB.  One reported near Altona, MB.
  • Niverville Tornado (May 31, 2008); a tornado touches down in Niverville, MB.
  • Southern Manitoba June Tornado Outbreak (June 27, 2008); 5 tornadoes touch down in Manitoba near Gladstone, Neepawa, Arden, Westbourne and MacGregor.
  • Winnipeg Tornado (June 1, 2009); Unconfirmed tornado reported in Winnipeg near the McPhillips Athletic.  Trees toppled on houses and a semi-trailer flipped over on Portage Ave and the Perimeter Highway.
  • Southern Ontario Outbreak of 2009 (August 20, 2009); 18 confirmed tornadoes, the largest outbreak in Canadian history.  They were:
    – F2 tornado from Durham to Markdale; 1 death, many serious injuries.
    – F2 tornado in Carksburg
    – F2 tornado in Vaughan; 3.5 km path through the Woodbridge neighborhood
    – F2 tornado in Vaughan; 2.7 km path through the Maple neighborhood.  This and the previous tornado resulted in hundreds of homes being damaged.
    – F1 tornado in Newmarket
    – F1 tornado in Milton
    – F0 tornado in Moonstone
    – F1 tornado in Ril Lake
    – F0 tornado in Dollars Lake
    – F1 tornado in Gravenhurst
    – F1 tornado from New Lowel to Edenvale; 12.6 km path
    – F1 tornado in Haliburton
    – F1 tornado in Haliburton Forest
    – F0 tornado in Redstone Lake
    – F1 tornado in Arnstein
    – F1 tornado in Carlow/Mayo
    – F1 tornado in Rice Lake
    – F0 tornado in Orono
  • Leamington, ON (June 6, 2010); F2 tornado went from Harrow through Kingsville and Leamington, ON.  No deaths or injuries, but significant damage.

This is by no means a comprehensive list.  Most of this information was gathered from here and I suggest you visit if you want more comprehensive information.  This is to show that tornadoes are quite a common occurrence in Canada and it is important that people are aware of the danger they pose.  Ensure you have a plan for your household on what course of action to take should your life or property be threatened by a tornado.  As the summer heats up in the Prairies, so does the risk that the unfortunate news coming out of the states could be repeated here.