Thursday, August 18, 2011

Severe thunderstorms roll through Winnipeg/ northern RRV








After dodging thunderstorms much of the summer, a line of severe thunderstorms pushed across Winnipeg Thursday evening, bringing heavy rain, intense lightning, strong winds and marble to toonie size hail to parts of the city. The line of thunderstorms developed northwest of the city Thursday evening and pushed across the city between 8:50 and 9:30 pm preceded by an impressive shelf cloud ahead of the storm (see photos). The storms brought some welcome rain of 15-25 mm across much of the city including 21 mm at YWG airport.. the heaviest rainfall of the summer, and the first daily rainfall over 5 mm at the airport since June 22nd. The line of storms was triggered by a cold front pushing across southern MB, which will usher in cooler weather for the weekend. Winnipeg hit 31C Thursday.. the 16th occurrence of 30C plus temperatures this summer.

Photos above courtesy of Winnipeg Free Press (top) and Weather Network (lower 3) See additional photos from CTV Winnipeg.

34 comments:

  1. by far best tstorm this season in Winnipeg/ nickle size hail, drenching rain and strong wind gusts.

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  2. 21 mm of rain at YWG airport yesterday which ends our run at driest summer ever (total now at 83.5 mm). Oh well, if we were going to lose the record, that was a great way to do it!

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  3. I gotta tell you that was the best storm Ive seen in years. I did go storm chasing. We drove up highway 7 to highway 67 then drove east towards selkirk and took highway 8 north.we stopped at one of the dirt roads (south of petersfeild) to get a better veiw. I had a perfect vantage point to see a really good lightshow, you could see the whole thing develop north to south from one small storm cell to a awesome line. I did notice some bowing as it was headed south east, I also noticed a little rotation to my west,nothing occured or formed. On our way back we had noticed a lot of stormchasers that were also watching the storm, we eventually drove into the storm on the way back it was just incredible there was just a black mass of clouds that almost looked like a farmers feilds dirt. as we drove in the rain was just blinding, we couldn't even see the road, I thought we were like in for a tornado with the way the winds were. I'd never seen rain like that in my life, freakin awesome. We had gotten out of the storm and when driving back we had gotten into it again although not as bad. we had also drove by the same place where i beleive rob was at same point as you had mentioned we had seen the same crowd of people in the park on the way there. we had gotten in the peg and the lightning was just insane! The gutters at shoppers (st.james) at portage ave and olive were just pouring out flooding the backlane. We got home to see tree branches everywhere, we had lost cable for 10 min. Nothing big. Overall that was a storm that topped my charts from last years at victoria beach. Even though this one had rainwater that smelled like lake manitoba. Awesome, i hope to see another one like this later this august in the city, when I'm here.

    One things for sure there goes our sheilds. What do you think of my adventure?

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  4. Oh jezze, rob do you mind deleting my second commment, and could you leave the one comment on. it's a duplicate, i beleive there was a glitch when I posted. Thanks.

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  5. oops, sorry turns out there wasn't a glitch. never mind you don't have to delete a comment thanks.

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  6. Sounds like you had fun Mike =) Glad to see all went well. Almost forgot how big storms can get here, was very nice to finally have it.

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  7. Glad your stormchase was successful Mike! What impressed me most about this storm was how it kept getting worse as it was approaching the city.. and intensifying so quickly on the southwest flank. Even 30 minutes before it hit I thought it would go mainly north of us. I just headed north at the last minute and thought I'd catch the tail end of it. Instead, it came in full force. As I said, a nice surprise.. something I wasn't expecting, which makes weather that much more exciting.. :)

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  8. I didn't need to storm chase, I watched it from a gazebo in Waverley Heights. It was almost like being outside, except much less water. I thoroughly enjoyed it, first time in years I've been outside in a thunderstorm, errr... I mean a thunderstorm event. I think my place in River Heights didn't get as much rain. Hard to tell because the soil soaked it up like a sponge.

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  9. From what I remember, it looked like an outflow boundary may have been the final kick needed for storm to fire south of the main cluster in the Interlake.

    Thoughts on this or am I off my rocker?

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  10. The interaction of the outflow/ lake breeze boundaries with the cold front allowed storms to build south just enough.

    Hopefully tomorrow we can get another round of convection with a wave dropping down in NW flow. Instability for severe storms will be lacking, however if we can get t/td's of 21/13 by noon it may yield 500 to 750 J/kg CAPE. With a lite NW flow we may see some relatively slow-moving lake breeze convergence cells coming down. Only catch is timing of wave.. it looks to move out by early to mid-afternoon.

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  11. I was still quite amazed on how quick that storm formed to the south. I thought winnipeg never saw anything until i got home. Also it felt like we were in a RFD or rear flank downdraft as the winds were insane and blowing horizontally at us, i thought I was done for. Even the rain seemed to smell like lake water. this morning i had heard that someone reported a tornado north of the city, we were in that zone, I bet one was right nearby us. how bad was it in the city? describe the storms structure.

    Thanks.

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  12. Mike!
    Here in St James, on Portage and near Moray it was a wide low hanging shelf cloud which brought the gusty winds 5 mins before the rain even hit. Then a nice wall of water hit with stronger winds!

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  13. Rob!
    On the radar image that you included in your post, after clicking on the link, What do all those Green and Red Meso circles mean??? Why are some of the circles large and others smaller????

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  14. Red circle means radar is detecting rotation at 3 levels (low, medium and high), while green is at one level only (yellow is two). The size of the circle correlates to the strength of the velocity couplet.. the larger the circle, the stronger the rotation detected. Note that this mesocyclone algorithm often overdetects rotation with strong lines, with a lot of false alarms.

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  15. We'll see if we get a shot of convection today with some storms forming along that shortwave sliding down from the north in that upper NW flow.

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  16. What's the chance of beausejour getting a storm today? As i'll be spending the day there. let me know thanks.

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  17. Mike , you have a better chance of storms where you are, compared to Winnipeg!!!

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  18. I agree anywhere NE of the city will have the best shot of seeing something.

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  19. I captured some RADAR imagery from this event. Check it out here:

    http://www.umanitoba.ca/environment/envirogeog/weather/aug182011.html

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  20. You can see the interaction of several boundaries on those radar loops..

    Strong outflow boundary from convergent line of showers/ tshowers off to our NE dropping straight south and will reach Winnipeg shortly. Slight chance something may pop as it interacts with cumulus field coming across L Manitoba.

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  21. Small storm on the #1 halfway between Winnipeg and Elie!!

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  22. Beautiful full rainbow over city with setting sun to west and passing shower to southeast.. nice!

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  23. Anybody else having problems logging onto my website today? I can't seem to get in..

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  24. Yes!
    I had a problem with some of the pages loading but I kept hitting the refresh button and eventully got on the page I wanted!!

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  25. Mike Some of the best/ nastiest storms I recall were in Beausejour. In fact they were coincidentally on Saturday nights in August. Won't say how long ago but they were still parking diagonally and you could boost many cars with a crank....
    Movie nite as it was called brought us in from two popular campgrounds 2 miles away. We were dropped off and picked up after. Many saturday nights we went back to a cacophony of TSs. One night we were picked up late. Trees as big as 1.5 feet in diameter had to be hauled off the road (adjacent to the river) to travel home.
    None of us had heard anything in the theater but we were awstuck at the damage the next day.

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  26. Thanks for the radar loops Dave. Too bad EC doesn't provide doppler data to the general public like in the states. Our TV news stations always brag about having 'live doppler' but only show rainfall intensity (and pretty crappy versions at that; I'm not sure if they even know what doppler is).

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  27. Thanks for the radar captures on Thursday's storm Dave.. nice event to archive. By the way, were quarters the biggest hail reported in Winnipeg? Somebody on my blog reported toonies in east Charleswood..

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  28. Yeah, the biggest in the city reported to EC was quarters. I caught golf balls, maybe bigger, 8 km SW of Woodlands at about 8:10 PM.

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  29. Rob!
    With these hot temperatures on Monday and Tuesday will there be any surge of dewpoints or will it be a very dry airmass???

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  30. Anonymous..

    Yes, it's a shame that EC can't provide better radar images to the general public.. including Doppler velocity for those who know how to interpret it. Just because many people wouldn't use it doesn't mean everyone should be denied access to it, IMHO. Plus, what better way to educate people about Doppler products than seeing them in real time over and over.

    In the meantime, you can get Canadian Doppler radar imagery from Weather Underground (go figure, you have to go to an American source to access better Canadian radar data) Just type in the local city name and click on the radar which should be closest default radar. I'm not crazy about WU's background, but at least you can get some higher resolution radar data for Canadian localities within Doppler range (in Canada, only about 120 km from the radar site)

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  31. daniel..

    Dewpoints are progged to rise into mid teens Monday and upper teens Tuesday.. not terribly oppressive for temperatures in the 30s. It's getting more difficult to get those mid 20 dewpoints (thank goodness!) now that summer is nearing an end and crops are maturing and being harvested. Plus, we've been so dry here which has also kept our dewpoints lower in the northern RRV.

    Interestingly NAM shows Winnipeg's dewpoint dropping into the single digits Tuesday afternoon while we soar to 38C (100F) as we get into a westerly flow. 850 mb temps are progged to rise to 25C Tuesday afternoon, so with a favourable west to SW downslope flow for Winnipeg, 38C may not be out of the question. Tuesday could be the hottest day of the summer!

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  32. Thanks for that info Rob!
    If we do hit 38C that will be quite the event!!
    Meanwhile residents of say...Dallas Tx would laugh at us as they have hit 54 days at 100F or higher!!!

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  33. Wow, thanks for the doppler source Rob. I look at doppler for US locations on Weather Underground, but just assumed it wasn't available in Canada because EC doesn't provide it.

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  34. It never stormed in beausejour yesterday, just had some heavy rain showers. Although as methusala mentioned beausejour has seen some big storms over the years, and still can today. I never saw any yesterday which is ironic as it was always saturdays when the big ones hit.

    I'm also very much looking forward to seeing our possible hottest day of the summer. 38C would be amazing, although I would like for it to be humid. Rob is it possible we could break a record on monday or tuesday?

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