Tuesday, June 14, 2011

Unsettled pattern this week..

Generally warm but unsettled conditions are expected over southern Manitoba this week as a large upper low pressure system settles over western Canada. This will put southern Manitoba in a southwest upper flow of unstable air through the rest of the week with periodic showers and thunderstorms as impulses move along the upper flow. Unfortunately, it looks like southwest Manitoba will bear the brunt of the heaviest precipitation during this period, with an increased chance of showers and thunderstorms the further west you go. The Red River valley will be somewhat drier with a mix of clouds and sunshine the rest of the week, and a chance of showers and thunderstorms each day. Due to the relatively slow motion of these storms, and the higher dewpoints advecting into southern Manitoba, rainfall will be very heavy with some of these storms, with local rainfall amounts of 25 to 50 mm, and in some cases higher amounts with training cells. This will put waterlogged SW Manitoba in a highly vulnerable situation depending on where the heaviest convection fires up.

34 comments:

  1. Models have a very difficult time resolving precipitation in these kind of situations since it's highly convectively driven. As a result, automated forecasts from the models may go from "Sunny" one day to "showers " or "Rain" the next, back to "sunny" again the day after. Ignore these flip flops.. this is just an indication that the weather pattern is unstable.. and that pcpn is possible virtually each day, but much of the time could be rain free as well.

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  2. WHOA!
    Parts of North Dakota are getting slammed with very heavy rain this afternoon with flash flood warnings for some area's.
    I see some storms are firing up ahead of that area of rain, which does not surpirse me considering how warm and humid we are!

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  3. hey Rob your wx station is stuck!

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  4. Southwestern Manitoba (Brandon's) forecast calls for 30-40mm of rain tonight, 5-10mm tomorrow, another 5-10 mm tomorrow night!
    That is unreal.No break for them!

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  5. Some pretty heavy rain reported today over the Manitou..St Leon..Somerset areas. 20 to 40 mm of rain since this afternoon according to CWB Weatherbug, MB AG and Wx Underground stations in that area.

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  6. Parents are getting a good storm in Elie right now!!

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  7. Looks like Winnipeg is FINALLY set to see some storms...at least the west side of the city!

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  8. Did anyone else get strong winds with that shelf cloud>>??

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  9. Nice gust front moving through Charleswood with thunderstorm just to our west.. just starting to rain now. Ominous looking clouds..

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  10. 72 km/h wind gust at the airport with that gust front!!

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  11. Some thunderstorms rolling through now. Haven't checked the shelf cloud out. Does anyone have any pics of it?

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  12. Just a quick little downpour here in Chalreswood.. only 0.5 mm so far. But much heavier just to the west of me with 10 mm past 30 minutes down the road in Headingley..

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  13. Rob,
    Could enough warm air Sneak into southern Manitoba on Friday so we could get out first 30 of the season....maybe?

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  14. daniel.. Current models are indicating 850 mb temperatures around 14C for Friday, which would translate to about 25-27C for Winnipeg given a southerly flow and rather high dewpoints. 30C is an outside chance if 850 mb temperatures get up to 18C or higher.. Whatever the case, it will certainly feel like 30C Friday with the humidity and sunshine.. a muggy summerlike day.. with perhaps some thunderstorms moving in Friday night.

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  15. We followed a major 7 pm downpour from Morden to Winnipeg last night . Any amounts for the Morden winkler area??

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  16. anonymous..

    Officially, only about 5-10 mm in Morden-Winkler areas last night with 15 mm in Carman, but locally higher amounts of 20-30 mm were possible within that line.

    Speaking of rain (what else can we talk about?) another 44 mm of rain in Souris since midnight (SW of Brandon), which gives them 48 mm since yesterday, and a whopping 280 mm since May 1st. Given the potential for another round of heavy rain over SW Manitoba Friday into Friday night, Souris will likely be over the 300 mm mark by the weekend..

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  17. That was quite the intense downpour here in Winnipeg! A quick 5mm for sure!

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  18. This comment has been removed by the author.

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  19. If it's not to late, I good poll question! Will Winnipeg hit the first 30 C tomorrow!!???

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  20. Looks like Southern Manitoba is set to recieve some very heavy rain today! Amounts in excess of 25mm is not out of the question!

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  21. Another system and another round of weakening precip moving in to the Winnipeg region. Showers are associated with an area of 850 hPa warm and moist advection.. but forcing is weak and disorganized. Models show another round of precip. moving up overnight into the early hours of tomorrow along a cold front.. but with loss of daytime heating and LLJ off to our north I am a bit skeptical.

    We are stuck in a pattern in which omega block keeps re-establishing itself over N Manitoba and NW Ontario.. that threatens to be a droughty scenario for areas off to our NE - while SW of here systems continually get deflected and experience drenching rains. We are right on the edge of things here with many rounds of left-over, weakening convection..

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  22. For sure I'm not seeing things!
    The forecast is calling for wall to wall sunshine and warm temperatures, I know there may be an odd shower and storm here and there, but could it be we are turning the tide toward a warm and dry weather pattern... Today was a good start!

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  23. Ya think It is kinda toasty here today!
    Oklahoma City is sitting at 104 F with a 67F dewpoint!
    Oh MY....I could not imagine being in that torrid heat!

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  24. Looks like I opened my mouth to soon...wall to wall sunshine???
    Looks like a system is set to hit us from the south again. Maybe it could still miss us>>???

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  25. EC sure is having a difficult time forecasting these waves of low level cloud and presip. Makes it hard to do any outdoor planning.

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  26. Not really just assume its going to rain. You will be right most of the time. LOL

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  27. Have not heard from Rob as of late.
    Would like to hear what he has to say about this next system!!!

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  28. Jeff Masters Friday Blog about the links between the Montana Rains, the North Dakota, Missouri River Floods and the Joplin Tornado outbreak are worth the read. My name or
    http://www.wunderground.com/blog/JeffMasters.

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  29. Depending on which model you believe, Winnipeg will either get a passing sprinkle Tuesday or a day-long soaking rain.

    General consensus is that heaviest rain will fall along and south of the international border where a good 25-50 mm is likely Tuesday into Wednesday with this slow moving and energetic system, with locally higher amounts of 50-100 mm possible. How far north the rain shield spreads is the big question, and this is what has been causing the inconsistency in the forecasts for Tue/Wed in Winnipeg from sunshine one day to rain the next (automated forecasts don't care about consistency)

    Given the expected track of the low across eastern South Dakota and into Minnesota, the best bet for heaviest rainfall over southern MB would be over the southern RRV and SE MB, with rain spreading up to the TransCanada and Winnipeg, falling off sharply north of the TC. Right now, ensembles are suggesting at least 10-20 mm for Winnipeg.. but that could change sharply depending on where this northern edge ends up. FWIW.. latest NAM this evening .. and to a lesser extent the RGEM.. have bulk of rain missing Winnipeg just to the south of us.

    I'll try to post something on this system late tonight or tomorrow (too busy these days to keep up with all this weather!)

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  30. The Correct Link to Jeff Masters Blog... Joplin Tornado/Montana Monsoons/North Dakota/Iowa Floods Links is
    http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=1826

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  31. Any precipitation that reaches us will have to overcome an increasingly dry, low level, easterly flow... a common situation here. In the upper levels, omega block transitions to more of rex block with upper high ending up almost directly north of the low moving into the midwest. Typically in these situations, most of the precipitation stays south of us.

    The increased moisture feed coming out of the gulf is only part of the picture, the persistent upper blocking over western Hudson bay is displacing most of this moisture transport to the southwest where it encounters an upslope regime. There is likely some feedback that is stabilizing this pattern.

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  32. I wonder if we will see our first 30C of the season in June or if we have to wait till July??

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  33. Maybe August? lol

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