Thursday, June 14, 2012

Thunderstorms over RRV/SE MB today.. unsettled weather pattern continues into next week

A roller coaster weather pattern is expected over the next few days over southern Manitoba as a series of disturbances race across the central continent every 2-3 days. The result will be alternating days of sunshine and unsettled weather with showers and thunderstorms every other day or two.  For today, a low pressure system tracking through the Interlake will swing a frontal trough across the Red River Valley, setting the stage for thunderstorm development this afternoon mainly east of the Red River valley, although Winnipeg may see some thunderstorms as well. Some of the storms could be strong with heavy rainfall and hail especially over Southeast MB and closer to the Ontario border. Things will dry out tonight with a nice day shaping up Friday with sunshine and warm temperatures in the mid 20s. Another band of showers and thunderstorms is possible Saturday, again with locally heavy rain rain possible, with a drier day forecast Sunday for Father's Day, and the annual Manitoba Marathon. More unsettled weather is expected Monday into Tuesday.

51 comments:

  1. It could turn out to be a very interesting couple of days here, the latest model runs show some thunderstorm activity to contend with today before we see sunshine return for Friday Afternoon and evning. Things look like they will change for late friday night into Saturday as an MCS looks to develop in North Dakota and move northwards into the southern part Of the province according to latest NAM runs. It will likely end up being a bow echo or a squall line, but that will not last all day. Saturday afternoon some lingering instability is likely so maybe some rumbles of thunder Nothing significant. Saturday Night we will see a reprieve,before we get another big round of storms Sunday Evening. This will likely occur out ahead of another low pressure system that will march across the region. I don`t know how severe they will be but Rob will likely keep us to date....

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  2. Line of showers popping up to the west of Winnipeg along the cold frontal trof.. some lightning strikes noted between here and Portage. This line will be the trigger for stronger storms to our east this afternoon..

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  3. Rob,

    question....

    With what appears to be a MCS pushing across Southern MB tomorrow night, will this affect Winnipeg and any severe threats with it?

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  4. Mike,

    It sure does look like we've got more storms on the way. GFS is also advertising an MCS forming to our southwest/west tomorrow evening and pushing through overnight into Saturday morning. Instability doesn't look great but moisture/LLJ should help support the complex through the night.

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  5. Soo, sunday during the day looks nice, but the eve is looking like we will get t-storms? Wonderimg because was hoping to take my son to the ex sun eve..

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  6. What are the chances for thunderstorms here in Winnipeg between tomorrow and monday? seems like convective activity is going around winnipeg but missing us here this week.

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  7. Next system looks similar to today's.. however, LLJ looks weaker out ahead of the system and focused to our SE. Left exit region of upper jet will be over interlake region overnite Friday, and instability overnite Friday looks very limited. I would expect some convection to form under the upper trough in Saskatchewan during the day tomorrow. Without much upper support and lack of instability, I think a lot of the convection should weaken as it drifts east Friday nite. Best chance for nocturnal convection will be across N Dakota from the looks of things. If surface trough comes thru Saturday morning, it will not allow enough time for surface destabilization.. good dynamics for possible surface based tstorms over eastern Manitoba and NW Ontario (like today).

    Daniel

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  8. As Daniel mentioned, best focus for nocturnal storm tonight will be over ND before MCS enhanced pcpn shield moves over RRV/SE MB Saturday as upper trof moves through. NAM and GEM painting some significant rainfall over RRV Saturday with amounts of 25 to 35 mm possible. We'll see how that develops.. models have been all over the place with amounts and location of this heavy rain axis for Saturday, which will largely depend on convective activity to our south and west tonight. Regardless, potential for heavy rainfall over RRV/SE MB for Saturday..

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  9. Yeah, thunderstorm potential in general doesn't look good here in S MB tonight/tomorrow morning. Could be a soaker, though.

    Things keep trending up for Sunday, however. Looks like a pretty darn good thunderstorm/severe set-up.

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  10. All the 12Z models now show 20-30 mm for tomorrow morning as Rob mentioned. Looks like they blow up precipitation around 12Z Saturday in response to a focused area of lift rotating around the upper low, and the left exit region of 500 hPa jet. Still looks like convection is being overplayed though, with only 250-500 J/Kg MUCAPE and no LLJ.

    Daniel

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  11. Lots of TORNADO watches & warnings for SK!

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  12. Any early thoughts on Sunday, Daniel? Looks promising if we can get 1,000-2,000 J/KG of instability. Shear looks real good with an evening/overnight frontal passage.

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  13. Hoping for some action on Sunday in Southern Manitoba, any details?

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  14. What I meant to say is that I am hoping for severe weather on Sunday, any possibilty of storms Sunday afternoon/evening to overnight?

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  15. 20 to 30 mm of rain over the western Red River valley so far this morning, with about 10 mm so far in Winnipeg. Looks like we'll be in line for another 10-15 mm or so before this moves through by afternoon. Getting tired of this unsettled weather.. really would like to see a nice week or two of solid sunshine and warmth.

    As for thunderstorm potential Sunday, looks like we could be see some storms by late afternoon/evening as another upper trof advances towards us. Pretty good shear Sunday, but energy may be limited in Winnipeg with high temps only in the low 20s, and dewpoints in the mid teens for CAPES of 1000 J/kg or so. Better energy values to our south and west. SPC is carrying a slight risk of severe through eastern ND to the MB border, with hail as the main threat.

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  16. We just had three days in the mid twenties so we can't complain if we get a bit of rain this morning.

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  17. Temperatures in the mid-twenties is all fine and well, but I think we do need to dry out at the same time.

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  18. Yesterday was nice too. Alternating days of sunshine and rain are fine why does it have to be 2 weeks of nothing? Often things dry out too much in that long of stretch without anything unless you've just had a biblical flood prior to. We just had a yearlong sub-drought so this is still welcome relief. Nobody is in a flooding situation so yes I definitely wouldn't complain. All in good balance Rob :)

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  19. Nice sunny breaks!

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  20. Rob, did we get close to your perdictions on rain or did we get more?

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  21. Any chance of an MCS rolling through tomorrow night?

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  22. I think we're going to have to start calling you 'MCS Mike'!

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  23. This comment has been removed by the author.

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  24. Lol I do love storms, is one still looking likely tmrw? That's all I'd like to know

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  25. Complicated forecast fort tomorrow.. haven't had much time to post. We'll likely be seeing clouds and a band of rain associated with elevated moisture transport ahead of a broad upper trough (although the bulk of it appears to affect the interlake). That will limit instability tomorrow as mentioned. Some clearing in behind the band will allow for SBCAPEs of 1000-1250 J/Kg, and along with some decent shear.. could see some scaterred thundstorms forming along the back edge of the rain band.

    Main potential for severe weather will be down in SE N Dakota late tomorrow afternoon.. as warm sector lifts up from the SW. SBCAPE will push 2250 J/Kg down there, south of a warm front and with 50-60 kts of deep shear. If they see enough clearing.. watch out.

    We will be in a persistent WSW flow aloft with potential for more unsettled weather the early part of the week.

    Daniel

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  26. Anonymous.. looks like about 15-20 mm for Winnpeg and SE MB today, with 20-30 mm over western RRV. I got about 18 mm, then just had another 1.5 mm "downpour" a few minutes ago, so I'm close to 20 mm for today. Ideal rainbow weather this evening with the setting sun backlighting passing showers.

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  27. Rob,

    question.....

    Is there any chance that we will get ouf of this cooler unsettled pattern or is that the kind of summer we are going to have?

    I have also heard rumblings of a warmer and drier than normal July and August, could that be possible?

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  28. Here we go again, another sharp warm front that we will likely stay north of once again tomorrow...mid to upper twenties in ND meanwhile barely twenty here in Southern Manitoba

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  29. June is still just a bit above normal.

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  30. South St Vital had 25 mm including the little downpours.

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  31. No I don't Think we'll be north of a warm front tomorrow. NAV Canada GFA shows a warm front will likely sit to the north of us by tomorrow at noon. It is a smaller system, though. Is there any relation to the other models you see?


    Click My name for The picture

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  32. Anonymous.. Unsettled weather in June is not unusual around here.. in fact, June is our wettest month of the year on average as the jet stream taps warmer and more humid air spreading up from the south, with frequent showers and thunderstorm activity, sometimes heavy. Typically, this frequency eases off in July and August as the jet stream pushes further north and evapotranspiration from crops and plants peaks. However, some years can be unsettled all summer long if the jet stream stays locked in a position along the international border.

    As for what will happen this year.. I honestly don't know. Long range forecasting requires a special skill set and expertise that I don't have, so I won't attempt a forecast. I do know that things can change quickly.. going from one type of pattern to another. Look at last year.. we were cool and wet until the end of June, then had two months of hot dry weather with no real indication that was going to happen. So an unsettled pattern in June does not necessarily mean it will stay like that all summer.

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  33. Looks like ideal weather conditions for the Manitoba Marathon tomorrow morning.. partly sunny skies, no rain, comfortable temperatures rising from 12C at 7 am to 20C by noon, comfortable humidity levels with dewpoints around 12c, and light winds before noon. Should result in some good running times.. good luck to all the participants!

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  34. Hi Rob,

    How influential is the 'rain begets rain' factor? I remember that this dominated the 2010 summer. I hope we get something that can overpower that, sort of like the monster ridge that built up in July 2007.

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  35. Andy.. Surface moisture is an important component of the precipitation process over the Prairies. Much of our summertime precipitation is driven by convection, and surface moisture is a critical ingredient for convection. But it's only one component. You also need the instability and lift to get precipitation to develop.. Without those, it becomes more difficult to initiate convection, even with plenty of surface moisture available. But certainly, the more surface moisture you have, the easier it is to generate more convection when you have the instability and lift. Conversely, in dry conditions, it becomes difficult to initiate convection even if instability and lift are present (drought begets drought situation)

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  36. Rob,

    question....

    Do you agree that the thunderstorm risk for today and tomorrow is very low?

    Also, i've noticed some warmer temps forecast for later in the week this coming week, could that be the beginning of a warming trend or just simply a brief warm spell?

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  37. CPC seems to be hinting at above normal temperatures in S. MB. in their short and long range forecasts, beginning late this week and into next weekend.

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  38. Yeah, I think thunderstorm risk for Winnipeg is low.. better chance over SW MB this evening where skies have cleared from this area of rain. (8th day in past 10 with measureable rain)

    As Chris mentioned, CPC long range maps hinting at above normal temps for the Prairies by the end of the week into next week, but I'd wait for the outlooks tomorrow before I start putting some faint hope in them (weekend CPC outlooks are automated)

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  39. Clouds held off nicely this morning, giving us a taste of sun at least. Trowal associated with upper trough now off to our NE.. mid level frontogenesis and deformation will focus over the interlake region overnite. Dry slot moves in before rain band slumps south again over Winnipeg between 4-7 PM tomorrow. Precipitation should have weakened to just light showers by that time.

    Meanwhile MCS is ongoing over extreme SE N Dakota and central Minnesota, associated with southern stream wave and LLJ. Tropical airmass south of the warm front with T/Td's of 32/22 common over parts of S Dakota and SW Minnesota. System has the potential to reach the east shores of L Superior by tomorrow.

    Another synoptic band of rain ahead of the next upper low moves in by late morning/ midday Tuesday. As with the past systems, instability (even aloft) will be locked up well to our south.

    Daniel

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  40. Some pretty substantial rainfall across the parkland region of western manitoba. 102 mm reported NW of Dauphin

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  41. Surprised no heavy rainfall warnings were issued there

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  42. I know this may be away's out yet, but the GFS is advertising temperatures in the low to mid 30 Degree Range and CAPE values over 3000 J/Kg in Southern Manitoba on July the 3rd. Something to keep an eye on.

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  43. That's extremely far out. Not even worth getting excited about, at this point. We're talking more than two weeks....

    A little bit disappointing that much of southern Manitoba escaped good thunderstorm activity the past week. The far southwest fared better with a couple of localized events.

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  44. Rob say isn't so! Another wknd for drips? ENOUGH.. 4 of the last 5  weekends each produced >20 mm. Close to 6 inches total.   I know its a great convenience for chasers but when's the B&B crowds turn. BBQ and Beach that is?

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  45. I'm hopeful that the weather will be turning drier and warmer by this weekend. Ensembles are showing little or no precip over the weekend, and today's CPC outlooks continue to indicate warmer than normal temps through mid continent through next week. Had another shower this evening giving 0.3 mm at my site, the 10th day of the past 12 with some measurable pcpn. Would love a nice long stretch of sunshine any time now..

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  46. Rob,

    Question....

    What are the models indicating in terms of temperatures in July and precip?

    Also, could our run of above normal temps end at 10 months or will June still somehow finish above normal?

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  47. Anonymous..

    Too early to say what July may be like.. and as I mentioned above, I'm not an expert in long range forecasts, so I try to stay way from giving long term predictions, especially in the absence of any large scale climatic signals. Just too difficult, especially in the summer.

    As for June, we're running just about normal, with this cool spell offsetting the warm start. If you believe CPC's 1-2 week outloooks, they point to warmer than normal temperatures for southern MB for the last part of June, so we could end up above normal again. Here's hoping!

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  48. Huge heat wave in Southern Ontario/Southern Quebec

    Toronto and Windsor both recorded a humidex of 42C which is the highest it's been this year in Canada.

    Lagoon City, Ontario also had a dewpoint of 25C, by far the most humid day in the country in 2012 so far.

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  49. ECMWF really showing this ridge holding strong through the first part of July. We may get a heat wave of our own!

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  50. Sure hope the ECMWF is right. I don't know about the rest of you, but I'm ready for a nice prolonged heat wave. This weather's depressing.. need some sunshine and heat!

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  51. Real battle zone to our south between the heat in the midwest and the cool unsettled weather here with strong jet stream and ample moisture/instability leading to persistent thunderstorms and flooding rains over northern Minnesota. Duluth has had more than 100 mm in the past 24 hours, with over 150 mm in some parts of the north shore. Emergency situation in Duluth with lots of flooding and damage.

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