Friday, June 08, 2012

Improving conditions today.. severe weather threat looms Saturday over southern Manitoba..

Unsettled weather this morning with occasional showers over the Red River valley will give way to a drier westerly flow as the day progresses, with breaks of sunshine this afternoon allowing temperatures to rise into the mid 20s. The dry and benign weather will continue tonight into most of Saturday, before a potential outbreak of severe weather develops over southern Manitoba later Saturday into Saturday night. Warm and humid conditions combined with increasingly favourable upper winds and an approaching frontal system will set the stage for thunderstorms to develop over southern Manitoba late Saturday, with a likelihood of some severe thunderstorms developing giving large hail, strong wind gusts and possible tornadoes.  At this point, it's still too early to say when and where thunderstorms will fire up Saturday, but current model guidance is hinting that the highest threat of severe thunderstorms will be over southwest Manitoba along the international border into southern Red River valley. Note though that much of southern Manitoba including Winnipeg will be under a threat of severe storms by later Saturday into Saturday night.  Stay tuned on this developing severe weather situation..

83 comments:

  1. Gotta wonder sometimes about the SCRIBE process (and the Phoenix project) for extended range forecasting. Yesterday's Saturday forecast for Winnipeg said "Mix of Sun and Cloud" just because SCRIBE was biased against the precip (as often happens in the extended range), while the model guidance(s) showed otherwise.

    It sure would be nice to take the extended forecast off auto-pilot sometimes when SCRIBE is obviously wrong. But I'm guessing management at MSC isn't in favour.

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  2. I hear you Garth. Those auto pilot text forecasts have a lot to be desired. They don't even mention thunderstorms, ever! A combination of poor programming and over-reliance on a single deterministic model.

    In more complicated situations, those auto-pilot forecasts simply can't convey what the models are trying to hint at. That's why these blogs, and graphical forecasts like your SpotWx.com, can provide so much more insight and useful information into the expected weather compared to those vague, poorly worded auto-pilot forecasts.

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  3. Decent downpours across the city this morning...latest radar shows the end of the rain here in Winnipeg with still some rain falling in the eastern and northern parts of winnipeg but should be out of here in the next hour or so, then maybe we can get some clearing as forecasted...i'd say 27C is a stretch today, likely more like 24C or 25C.

    Looking forward to seeing everybody's comments and opinions on waht may unfold tomorrow. Looking quite volatile at this point

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  4. Rob,

    Do you think tomorrow's forecasted high of 28C is optimistic or reachable?

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  5. I see EC has downgraded it's forecast high for today from 27C to 25C in it's 11AM update..that's sounds more realistic to me given the cloud cover that still remains

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  6. Yes, I think 28C tomorrow is quite reachable in Winnipeg.. provided we have enough sun through mid afternoon. 850 temps hit 18-19C, and with a southeast wind and sunshine, 28C is certainly reachable. Note that both the NAM and GFS are also forecasting highs of 28-29C for Winnipeg.

    The Euro on the other hand is going nuts with precip for Winnipeg late Saturday into Saturday night, with 80 mm of rain within 12 hours! I've never seen the Euro paint such high numbers for us before..

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  7. I am pinpointing the Red River Valley for potential tornadoes throughout tomorrow, as the NWS in FGF is mentioning a threat in the evening through our regions. I will have more thought on this later.

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  8. I agree Rob. Hopefully the increasing presence of model forecast data in the public domain will lead to some changes in how MSC/CMC creates and relays the public forecast. The proper balance between automation and human interpretation hasn't been found quite yet.

    Yes, hopeully the Euro is wrong for this weekend!

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  9. Rob,

    Do you think that Euro is overdoing the rain amounts of 80 mm for tomorrow night or is it possible?

    Looks like NAM is pinpointing tornado threat for the RRV with GFS still going with the slower solutions, still lots to sort out with this one i guess.

    It doesn't even appear like we will even get to 25C today...not as much clearing as expected i guess...still very muggy though

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  10. Euro has downgraded the rain amount. Now a reasonable 16mm for Sat and another 14mm for Sun.

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  11. well, it looks like we are finally getting some of that clearing...25C might still be a stretch considering it's already 3:00 and the clearing is partial but i guess you never know.

    NAM and GFS are still battling it out at last check. I still think GFS will win out on this one but we'll see what happens. I see SPC is leaning towards the NAM solution

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  12. those Euro numbers of 16 mm and 14 mm seems low for convective activity especially if the storms become slow movers

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  13. looks like NWS Grand Forks is going with the further west/slower solution GFS as they have completely thrown the NAM solution out the window....quite interesting to say the least

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  14. Hart Mountain (Porcupine Hills) had 87.9 mm in the last 24 hours. It's going to be awfully soggy up there by Monday.

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  15. The Grand Forks discussion going with the GFS solution because they are saying it will more of a SSW flow which generally means a slower moving system

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  16. Plenty of differing opinions on what model to believe for tomorrow... and corresponding severe weather threat over southern Manitoba. Tonight's run will be especially interesting as upper low coming into west coast becomes better resolved by the models which hopefully will bring more of a concensus on what will happen Saturday. Click on my name for yet another opinion on tomorrow's severe weather threat (from another Brad!)

    My personal opinion is that best severe weather threat will be along the US border of SW MB and southern RRV by late afternoon as cap breaks with supercells likely, pushing into RRV/SE MB into the evening hours. But, as always, we'll have to wait and see..

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  17. 18Z NAM run is looking scary for Sat evng.

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  18. Going over things, my current gut feeling is for a slightly slower system. Looking at some experimental ensemble products (a 42 member ensemble comprised of members from the CMC EPS and the NCEP), they have the surface low pushing into the central RRV by 06Z on Sunday; by that same time the NAM already has the surface low over the Northern Whiteshell, so there's quite a difference.

    The NAM is quicker than the ensembles, GFS, GEM-REG, GEM-GLB and the ECMWF...doesn't mean it's wrong, but it certainly has a lot to prove.

    Should the slower solution (the general consensus) be correct, the main threat area for tornadoes would be areas south and east of Brandon (the closer to the Int'l border the better) and into the extreme western Red River Valley. If the faster solution is correct, the tornado threat will shift eastwards and cover much of the Red River Valley, potentially including Winnipeg.

    If the slower solution is correct, there's still a good chance of a band of strong-to-severe thunderstorms rolling through Winnipeg mid-to-late evening with extremely heavy rain and the potential for wind gusts over 90km/h and large hail (over 1" in diameter).

    That's what I can glean from everything now. The models should start to provide a much clearer picture of what's going to be happening with the 00Z model run, as the main upper low has finally pushed onto the west coast and some sounding data under it will finally be integrated into the models. We should see them snapping to a solution fairly quickly.

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  19. Well, the NAM has caved and joined the slower solution party. That's pretty much the clarification we needed.

    Initial threat should be in SW MB, slowly shifting east through the evening. Tornadoes possible late afternoon through mid evening before an MCS takes shape.

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  20. 21Z NAM profile for Morris MB is about as classic a tornadic hodograph as you're going to get. Scary. Problem is still the cap with warm air at 700 mb keeping a lid on things.. but once she goes.. look out!

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  21. Added a comment to my blog, detailing tomorrows latest info on severe weather. Head over and have a look, always love more viewers.... http://mikesobs.blogspot.ca/

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  22. WOW! 81 knot wind gust at Minot early this morning with that MCS spreading across western ND!

    With the fog this morning and the overunning cloud from this MCS, we may be looking at a lot cloudier conditions than expected over RRV today which will limit our surface heating. Need some quick dissipation of this morning complex to see some decent heating this afternoon. SPC still only carrying a slight risk for severe today over ND.. they seem to be downplaying this situation due to strength of the cap and overestimation of surface moisture from models, although they do indicate a better chance of storms over southern MB.

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  23. According to CWB Weatherfarm mesonet, MCS line over SW MB has produced rainfall of 10-17 mm, with peak rainfall rates of 150 mm/hr. Max wind gust of 76 km/h at Goodlands near the US border.

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  24. I see EC has downgraded it's forecast high from 30C to 27C.

    Rob, do you think we'll even get to 27C and is the big storm potential for today beginning to decrease?

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  25. At last look now EC has downgraded the forecast high again...now 25C and a chance of showers near lunch time...it starting to look like we may not get the big storms at all today unless it does really heat up this afternoon which is starting to look unlikely

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  26. Based on motion on radar, looks like line will be passing through Winnipeg between 10-11 am.. if it holds together. Will likely be weakening as the morning progresses, but we will still likely see some precip out of it (of course, we have a lunchtime pool party planned!) Hopefully things can clear out quickly behind this complex this afternoon to allow some decent heating.. but it may not be enough. Storm threat looks better SW of Winnipeg where things will clear out sooner. Lots of variables to consider here.. not a clear cut situation.

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  27. Clearing already pushing into extreme SW MB. Cloud really not lingering behind this MCS very much, so should see a moist, capped environment over most areas in SW Manitoba this afternoon with strong surface heating. Still looks promising for regions west of the RRV, although I agree that the surface-based threat for the RRV is diminishing. Still potent amounts of MUCAPE available, so nocturnal storms aren't out of the question for us.

    The whole AWM team is heading out chasing today. You can follow along with a twitter stream on our site:

    http://aweathermoment.tumblr.com/post/24674161082/tornado-threat-to-develop-over-southern-manitoba-on#twitter-livestream

    Or you can just follow us on Twitter. We are @WeatherInThePeg, @steinbachwx and @lovestormsmb.

    I'll also be broadcasting to Spotter Network; I'll be the dot labeled Brad V.

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  28. Carberry received 16.6 mm in 1 hour.

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  29. 12Z NAM is hours late...wonderful.

    NOUS42 KWNO 091538
    ADMNFD
    SENIOR DUTY METEOROLOGIST NWS ADMINISTRATIVE MESSAGE
    NWS NCEP CENTRAL OPERATIONS CAMP SPRINGS MD
    1535Z SAT JUN 09 2012
    NCEP DEVELOPERS AND ANALYSTS CONTINUE TO TROUBLESHOOT THE 12Z NAM
    FORECAST JOB FAILURE...AT THIS POINT THE 12Z NAM IS 150 MINUTES
    DELAYED. A FIX IS BEING TESTED AND IF SUCCESSFUL DELAYS SHOULD
    MAX OUT AT APPROXIMATELY THREE HOURS...
    OREILLY/SDM/NCO/NCEP

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  30. Talk about a busted public forecast this early morning!

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  31. No kidding....30C with sun and cloud and chance of storms late this afternoon...some much for that...instead it's raining and cool....i have my doubts that we will even get to 25C even today

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  32. unless with clear out this afternoon i don't see us getting severe weather today nor tonight...seems like both GFS and NAM we're wrong also...neither called for the MCS complex that moved through north dakota overnight and southern manitoba this morning. That darn MCS just might have screwed everything up for later today's events

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  33. Rob,
    question....

    Do you think today and tonight's severe weather threat is diminishing?

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  34. Blue sky in the west already, so it will clear soon enough.

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  35. EC has put out a Severe Thunderstorm Watch for basically all of southwest manitoba....let the fun begin i guess...looks like lots of clearing going on to our west and south

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  36. Indeed a model failure. Did any of the models forsee the roughly 10mm or so that came through this morning?

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  37. Got SOAKED this morning. How's it looking at 4-5 PM for the city?

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  38. Am I seeing another threat for tomorrow now (my name for SPC day 2 issued at 1230 CDT) or
    http://www.spc.noaa.gov/products/outlook/day2otlk.html

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  39. The HRRR reflectivity model was all over the MCS. Showed it lasting the night and pushing across southern MB in the morning.

    Looking good for storms today. Sunshine across southern Manitoba with the warm front slowly shifting north. On Facebook, Reed Timmer says he is targetting the area between Virden and Pipestone for initiation later on.

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  40. The Dominator and Reed Timmer are at the border near Lyton, and Team TIV is in North Dakota heading this way, so we might have a Dominator vs. Team TIV show down right here in Manitoba. TIV is live streaming right now as well.

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  41. Is there still a chance for thunder storms this evening or at night?

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  42. Two cells just to the SE of Lake Manitoba on radar. Showing some purples...XWL starting to run hot as well?!

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  43. Elevated line of storms going north of the 850 hPa warm front and moving ENE. Outflow has pushed winds back to northerly at YWG. Meanwhile surface warm front inching up just north of Grand Forks now.

    For the short term.. HRRR shows convective initiation along the intl border off to the southwest by around 6 PM. Potentially dangerous situation for areas right along the American border. Model shows cells quickly merging into an elevated complex affecting the city by around 11 PM on the nose of LLJ.

    Best chance for tornadoes will be in the far southern RRV before 10 PM, tapping the warm front and higher surface based CAPE. For the Winnipeg the threat should be elevated with heavy rain, hail and strong straight-line winds.

    Region of post-frontal convection (although non-severe as best instability shifts east) associated with mid-level deformation and frontogenesis is progged to affect our region by tomorrow morning.

    Daniel

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  44. In Morden--starting to see a lot of haze and cloud to the West.

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  45. Surprised there isn't a warning out for that line north of Winnipeg.. if RADAR returns are calibrated correctly, cells of heavy rain are training west to east thru the northern RRV and southern Interlake..

    Daniel

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  46. Whew.. so much to talk about.. so little time! Just haven't had the time to comment today.. but keep on posting folks. Enjoy reading your posts.

    That line of heavy rain to the north of us has given 30-35 mm in the Teulon area according to Weatherfarm mesonet with more on the way.

    Still waiting for things to pop to our southwest.. SPC thinks initiation will take place between 6-7 pm. Best chance will be near surface low over central ND and along warm front along US border where supercells are likely, possibly tornadic. Still nothing dramatic developing as cap is holding tight.. but could see rapid explosive development once cap goes. Pins and needles time..

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  47. I see EC is beginning to end the severe weather watch for parts of Southern Manitoba in the southwest because they are saying it appears things have stabilized over there ending the threat....very interesting...the more evening goes on without nothing happening i'd say the threats will end elsewhere as well...i guess the capping is just too strong at least right now

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  48. Looks like things may finally get going...let the fun begin

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  49. here we go, tornado watch now for pilot mound and emerson areas. Good luck to you chasers out there in the pilot mound area

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  50. Cluster trying to organize west of Morden.. another lone cell just popped south of the border as well.

    Daniel

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  51. let the show begin

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  52. Oooowweeee! Anyone in Gretna?

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  53. The cell in north dakota nearing the border nearing emerson looks to be a promising one.. Starting to take a more healthy form...wouldnt doubt it if there was a tornado warning on that one.

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  54. Yup..Tornado warning on that exact cell just now

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  55. Decent cells also passing off to the NW of the city.. had a nice view of a while back.

    Daniel

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  56. That Emerson cell was looking promising.. but looks like it's collapsing somewhat as it crosses the border. Just doesn't appear to be getting the sustained updrafts to keep going.. which is surprising given the instability and shear in that area. Very puzzling that things haven't exploded more.. that cap must really be doing its thing.

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  57. Well gotta it certainly does not appear like anything significant is going to occur tonight other than those cells in the emerson area heading east unless something dramatic changes i suspect that EC could end the watch for us and west of us soon. tHis almost seems lie a scenario that was overplayed by most either that the cap is just too strong...any opinions on this situations?

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  58. it seems to me that models seemed to have overlooked the capping today

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  59. Those cells across on the border are starting to get better organized.. some hints of them bowing out. They will pass SE of the city unless there is further development back to the NW

    Daniel

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  60. Rob,

    Question...

    I have noticed that once again temps in North Dakota we're like some 10 to 12 degrees warmer than us.example..winnipeg today 24C grand forks 34C..that's a few times now that this has happened this year...is there a reason for that or that just simply the kinda summer it's going to be?

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  61. Any Big thunderstorms later tonight, damaging winds,hail?

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  62. Anonymous.. These types of sharp warm fronts lying along the intl border with 30c+ plus temps to the south and mid 20s to the north happen every year.. usually early and late in the summer season. No indication that this pattern will persist all summer.. as Winnipeg can easily get south of the warm front during the mid summer as the jet stream pushes further north.

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  63. As daniel noted.. strong to severe cells to our south will likely pass just to the southeast of Winnipeg. Looking less likely that Winnipeg will see something big this evening.. unless something blows up quickly to our southwest.

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  64. new cell forming to the NW south of Brunkild..

    Daniel

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  65. didn't see your comment Rob, that cell just popped up..

    Daniel

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  66. Looks now like at least the SE part of the city will be affected.. torrential rain and hail the main threats, with potentially damaging straight line winds if the storms can bow a bit more within the next hour.

    Daniel

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  67. Yeah I see that now daniel.. that cell popped up quickly south of Sanford. South end of Winnipeg will see something soon.

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  68. That cell is rapidly intensifying.. wonder if chasers are on it. I would watch for rotation on the SW flank of the storm.

    Daniel

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  69. No rotation yet.

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  70. Big hail. Almost golfball in St. James.

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  71. 9:55 PM some sporadic very light hail as the storm went by tot he west of us! Chris IN Westwood

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  72. I'm in a flippen tent at Polo Park watching the circus, sounds like the roof was going to drop. What's happening? Has the cell passed?

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  73. 25 mm hail reported at YWG airport (approaching golf-ball sized).

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  74. 4 cm hail (golf ball) at my place in Charleswood about 15 minutes ago.. nuts! Shredded leaves everywhere..

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  75. The last warning said some tennis-ball sized hail was reported! I wonder where. Golf-ball was big enough for my comfort level.

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  76. no hail at all here in River Grove. Nice light show, then some moderate wind and rain. Nothing too intense.

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  77. Im in the northeast part of the city and i just recieved hail for about 10 minutes..and the biggest i found was golf ball..some where very smooth and round to!

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  78. No hail in La Salle and just a little rain.

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  79. I'm in Steinbach and it missed us. Some rain and no hail.

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  80. Note the 25mm hail notation at the end of the 0254Z report:

    CYWG 100323Z 08012G18KT 15SM FEW060 SCT077 SCT096 18/ RMK CF1AC2AC1 CB TOPS NE QUAD
    CYWG 100300Z 08018G24KT 10SM -SHRA FEW005 BKN060CB BKN074 18/17 A2942 RERAGR RMK SF1CB4AC1 TS MVG RPDLY NE SLP965
    CYWG 100254Z 09018G24KT 1/2SM R13/P6000FT/N R36/P6000FT/N SHRAGR BKN065CB 19/ RMK CB7 25MM HAIL
    CYWG 100247Z 08016G25KT 15SM TS VCSH BKN065CB BKN095 19/ RMK CB5AC2 FRQ LTGIC

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  81. It was a good chase today, but we, nor anybody I know of, saw a tornado.

    We set up shop fairly early in Pilot Mound, ready for when the cap would break. After about an hour of sitting there and wonder what to do, Reed Timmer showed up, so I got a chance to meet & chat with him for a bit. Helped pass the time and he's a pretty nice guy.

    Unfortunately...the cap didn't break. While every model out there was showing convection over SW MB this afternoon, nothing happened. The environment was clearly primed for tornadoes, with copious amounts of wind shear and numbers towers trying to get going. For whatever reason things never went, regardless of all the forcing in the area.

    Storms started to fire further east in the RRV, so we quickly raced back that way, and decided to hang back and slowly track behind the storms along Hwy 201 & 75. We got a great lightning show, and a beautiful sunset, but it was quite clear that all the storms were elevated. With no hope of them becoming surface-based, there was certainly no hope of a tornado. There was hope for cells close to the international border, but I didn't particularly feel like chasing after dark into the woods near Sprague. We tracked north on 75 watching the great lightning and called it quits for the day.

    I feel pretty good about things; we were definitely in a prime spot and mother nature just didn't show up. Hopefully we can do this again sometime again this year!

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  82. Well, certainly not what anybody anticipated but that's nature for you sometimes. I agree with you all here it was definately a prime tornado day but that darn cap was just too strong which i guess is often a concern whenever a big storm event is possible is will that cap if it's present break...but it's still very early in the thunderstorm season and i'm sure this situation will present itself again at some point this summer

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  83. Strange day yesterday.. things didn't go where I thought they would, things went where I wasn't expecting. Very tough day to get a good handle on. Cap definitely was a bigger factor than expected in the southwest, and elevated stuff was more intense. Another example of Mother Nature showing us who's really in charge..

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