Friday, August 10, 2007

Severe storms slam Southern MB..

Strong long lived thunderstorms developed over east central Saskatchewan Thursday afternoon and tracked southeastward into the Lake of The Woods area by daybreak on Friday. These storms generated a large swath of golfball and larger hail from east central Saskatchewan into west central Manitoba late Thursday afternoon and evening then transformed into more severe winds as they continued tracking southeast from Lake Manitoba through Winnipeg and finally into the Lake of The Woods area during the overnight hours. The hail caused significant crop damage and several reports of windows smashed in houses and cars over west central Manitoba. (image shows sample of baseball size hail that fell in Dauphin)

The following are the preliminary severe events in Manitoba reported to Environment Canada up to 4 AM Friday.

Time of event location of event event type and comments
============= ================= =======================
4:05 PM .... Narol - Nickel sized hail
4:23 PM ..... pine ridge golf course - loonie sized hail
4:24 PM ..... Oakbank - Nickel sized hail
6:30 PM ..... 6 km west of San Clara - golfball sized hail
8:05 PM ..... Roblin - golfball sized hail
8:15 PM ..... 32 km nw of Dauphin - loonie sized hail
8:33 PM ..... Dauphin - 56 mm of rain in just over one hour.
8:44 PM ..... Dauphin - baseball sized hail. Extensive damage to cars, buildings and crops. Virtually every roof and car left outside in Dauphin suffered hail damage. Hail damage will likely exceed $50M. One of the most severe storms ever to affect area.
8:50 PM ... 8km south of Grandview - hen-egg sized hail.
9:20 PM .... Gilbert Plains - loonie sized hail.
9:35 PM .... Ste. Rose - Nickel sized hail.
10:15 PM ... 7 km east of Alonsa - golfball sized hail.
11:50 PM ... Delta beach - wind gust to 117 km/h.
1:15 to 1:30 AM .... Winnipeg - numerous reports of nickel to loonie sized hail and strong winds. Winnipeg airport had peak wind gusts of 100 km/h. Northern half of city was most affected with many trees down. One of the "top 10" storms for tree damage according to city forester. About 30 mm of rain fell over the north end of the city while areas south of Portage Ave received little or no rain.


  1. The big question is will there be any strong convection tonite? Some models depict a strong low level jet cranking up across Southern Manitoba before shifting into Northwestern Ontario by dawn.

    The jet will push some very moist air aloft into S Manitoba and potentially interact with a surface front that pushed north of Winnipeg this evening. However there is also a strong outflow boundary from Kenora to Grand Forks and on southwest. Which boundary the jet interacts if any is not clear.

    And what happens tonite will impact the timing of a cold front passage tomorrow...lots of convection could push the front sooner and clouds would keep the atmosphere stable ... A lack of convection and clouds may cause the front to hang up during peak heating hours setting up the chance for a severe weather outbreak in the afternoon.


  2. A couple of large tstorm complexes formed last nite. A very strong one that went thru Minnesota and one further west affecting Southwest Manitoba and Saskatchewan.

    Wow...the front really surged thru the region...quite a fresh, dry airmmass in its wake.


  3. Another round of strong warm air and moisture advection for Southen Manitoba on Sunday night and Monday. Storms formed in response to this forcing way up in the interlake and down in North Dakota...predicting exactly where the storms form is really frustrating!

    Looks like a good set up for storms/rain this late afternoon...but so far moisture return has not been that strong...the high dewpoints are way down to southwwest in the western Dakotas ... still, with a lot of dynamics and shear something could easily form ... lets see what happens!


  4. Dan..

    Dewpoints have really come up the past couple of hours with 17-20C values across the Red River valley and southwest MB. Still have a warm nose aloft that is keeping a lid on thunderstorm development, but with trough and strong upper jet moving in from the west, we could see tstorms popping up shortly. Nice storm south of us in ND has prompted a tornado warning for Grand Forks!

  5. Looks like a bust.. cap must have been too strong plus we had some smoke aloft from Montana forest fires that may have inhibited storm formation. Whatever the case, no rain again here in south Winnipeg where it's getting really dry. Only 3.6 mm rain so far this month..

  6. yeah...the area between highway 1 and 2 including Southwest Winnipeg cannot seem to buy any rain despite an active weather pattern and numerous chances of precip

    another huge MCS blew up over Minnesota tonite. I guess the low level jet and well defined warm front were focused there. The twin cities airport has picked up 90 mm of rain in the last 3 days after being in severe drought.

    Now it looks like maybe its our quickly thing can change!