Friday 9 May 2014

Brief Reprieve

     Winnipeg got brushed with some rain late yesterday evening associated with a Colorado Low to our south. Not much fell, but essentially the city was divided into two with the eastern half seeing the most. 2.0 mm fell here in south St Vital while no accumulation seems to have been recorded in the west part of the city, including at the airport.

     Spectacular sunny skies have returned for today. Although, there will be a bit of a north breeze of 20 to 30 km/h. We should reach a high around 15-16°C, possibly our warmest day so far this year. So far, our warmest day stands at 15.1°C on April 23.

     Tomorrow has the potential to be yet again the warmest day of the year. In fact, there is even potential we may reach our first 20°C of the year if skies are clear enough. We should reach around 19-20°C. Clouds will increase late in the day as a low pressure system begins to move in.

     The unsettled, cool conditions return Sunday. A few showers are likely on Sunday with lots of cloud. A few sunny breaks are possible at times. A rumble of thunder is also possible, especially in southeastern Manitoba.

     Yet another Colorado Low is expected to impact southern Manitoba to begin the work week with cloudy, cool and wet conditions expected Monday and Tuesday. It is too early to talk about rainfall amounts, but another significant rainfall is in the realm of possibility.

     Well below normal temperatures are expected for the remainder of the work week. Wednesday so far looks coolest with highs possibly only reaching high single digits. Slightly warmer weather is possible by next weekend, but generally below normal conditions look to persist for the foreseeable future. Normal highs next week range between 16 and 19°C.

26 comments:

  1. Looks like the CL next week will kind of stall over Mb; could be a potentail for a big rain fall... The GEM has 48 MM of rain; something to watch.

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  2. I've been asked a few times about the November pressure record we broke last year and how the top 7 highest daily pressure readings in November since 1953 all preceded cold winters (posted in the November summary here: http://jjwinnipegweather.blogspot.ca/2013/12/pleasant-start-to-november-but-cold-and.html). As a result, I've dug into these pressure stats a little more and gathered an archive of all the hourly pressure observations in November since 1953 and have gathered some statistics. Because I have some graphs, this post is continued via the following link:

    http://blogextra.weebly.com/novpressurecorrelation.html

    I'm basically just showing the statistics... you can infer what you will from them.

    Interestingly, I discovered that in 2011 we had tied with 1994 for the lowest average pressure reading in November on record since 1953. The average hourly station-level pressure reading was 98.21 kPa. The 1981-2010 normal is 98.65 kPa. Note that the average varies very little from year to year.

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    1. Great work and interesting results Julien? I suspect that these recent Hi's mght place further back if we had records from the 1880s and 1930s. Don.

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    2. Yeah, it's too bad there aren't any records for back then. Certainly would've been interesting to see the 1880's!

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  3. I've gathered the stats for longest streaks of below normal months since 1872... Note that the normal that I used to determine the deviation of a month is the average of the previous 30 years. For example, for 1976 let's just say, the normal used was the 1946-1975 normal. Prior to 1903 and 1904, either the 1872-1901 normal or 1873-1902 normal is used depending on if data in 1872 was available or not.

    Turns out we not only had 9 consecutive months of below normal Dec 2008-Aug 2009 but also last year from Sep 2012-May 2013... both the longest below normal streaks since 1950 (Dec 1949-Aug 1950) and tied 4th longest streaks of below normal months. If we get another 9 month-streak this year, it would be quite significant. We haven't had so many long cold streaks bunched together like this since the 1880's.

    Top 12 longest streaks of below normal months since 1872:
    1. 18 months (Dec 1882-May 1884)
    2. 14 months (Jul 1884-Aug 1885)
    3. 11 months (Oct 1887-Aug 1888)
    4. 9 months (Dec 1949-Aug 1950, Dec 2008-Aug 2009 and Sep 2012-May 2013)
    7. 8 months (June 1951-Jan 1952, Mar-Oct 1954, Nov 1978-Jun 1979, Oct 1995-May 1996 and Dec 2007-Jul 2008)

    As Rob had mentioned a couple days ago, the 1880's were remarkably cold with 3 streaks of 10 or more below normal months. The period of Dec 1882 to October 1885 was especially frigid with 33 out of 35 (94%) months averaging below normal, 16 (46%) of which were well below normal (more than 2°C below normal). It is believed that the massive eruption of Krakatoa in 1883 near Indonesia likely was a factor, disrupting weather patterns for the remainder of the decade.

    So far, this May would be the 8th consecutive below normal month.

    April was also the 5th consecutive month averaging over 3.5°C below normal, the longest such streak on record since 1872, rivaling even the 1880's. The previous record is just 3 consecutive months averaging more than 3.5°C below normal. Remarkable..

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    1. Krakatoa might get some of the credit but ironically this period followed one of the most active decades of Iceland Volcanic activity including the largest single eruption in their history Askja in March 1875 VEI 5 (Viti crater lake) Series of eruptions started in 1872 mostly Grimsvotn/Barbarbunga/Laki) the largest of which was a 1873 VEI 4 The series included every year until 1878 x(1877) Started up again in 1883 with eruptions every year til 1889( x1878) with confirmed VEI 2s in 1885 and 1887 Some of the others are not well documented as many citizens died and many emigrated to Manitoba (Gimli) North Dakota and Minnesota, where the fall out seems to be Icy cold but not poisonous gasses, and we shiver and shake from the cold every time there is a series of Major Iceland Volcanoes

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    2. Similarily the 1949,50 result may be explained by the Major eruption of Hekla in 1947,48 a VEI 4 which sent an ash cloud 30 Km up on March 29th The first major Icelandic eruption since 1918.(Katla 4+) The VEI 3 1970 and 1973 and 1980 were interspersed with 4 eruptions in Krafla in 1975, 1977(2) and 1980(3) and 1981(2).
      Pinatubo in 1991 and Heckla VEI 3 in 1991,and Barbarbunga/Grimsvotn VEI 3 Eruptions in 1996,and 1998. and 2000 rounded out the Millienium . This century we have 2 VEI 4s in 2010 *Eyjafjallajokull Eruption* and 2011 *Grimsvotn Eruption* .and a VEI 3 in 2004 (Grims).

      Do you think these eruptions perhaps at least the major ones or the significant clusters are effecting the Icelandic Low thus producing negative AO and NAO readings. Or are they lowering the temperature difference between the equator and the Artic... The drift would explain the similar effect of the massive Indonesian eruptions in 1815 and 1883 and 1991 by lowering the Equatorial temperatures and the Azores pressure gradient.
      I apologize for the length of this and will leave this for now as the next 3 days rain is far more interesting.
      See
      http://climatecrocks.com/2013/04/04/the-paradox-of-cold-continents-warm-arctic/

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  4. High of 16.4°C at the airport today.. Lots of 17's within city limits.

    I'm still hopeful there will be some 20°C readings tomorrow in the RRV... will somewhat depend on how much cloud is present. Southern Saskatchewan managed to see many 20°C readings today despite a fair amount of cloud so hopefully a similar story here tomorrow if high cloud is present. Nonetheless, if the airport does hit 20°C, it would tie for 18th latest first 20°C of the year since 1872. 1981-2010 normal first 20°C is April 20.

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  5. 20°C is looking like a slam dunk here now for today looking at sattellite. Even if it clouds up this afternoon, we're already at 14°C at 9 am and it's rising quickly. Looks like we should manage to reach between 20 and 22°C today... so I'm glad I stuck persistently with a 20°C day today.

    Tomorrow not looking AS wet as it did yesterday. Low looks to pass to our south in North Dakota at the moment instead of passing right through southern Manitoba. This will reduce our risk somewhat of some thunder, but the risk is still there, albeit very, very small. Showers remain possible. By the way, it will be too warm for any snow tomorrow. I've heard some rumbling about snow tomorrow, but I don't know where that comes from.. I wouldn't worry about snow tomorrow.

    Very uncertain, as usual, what will occur Monday and Tuesday with that Colorado Low. NAM appears most aggresssive at this point (farthest west, and has an obvious inverted trough right through southeastern Manitoba on Monday). Other than the GEM, other models further east with these features, such as the ECMWF which gives Winnipeg little to no rain.

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  6. Thanks for voting in the poll! Results are 50/50 with 3 of you expecting a 20°C day today while 3 others anticipate no 20°C, but close around 19°C.

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  7. Intresting reading your May weather history, JJ. Personally i'd rather have a cold, dry spring, winter, and fall, then have warmer winter, slightly warmer spring and fall (correct me if i'm wrong), but still have the risk of a snowfall almost all year round. In other words, i prefer winnipegs climate over calgarys.

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  8. Pretty amazing how the lake Winnipeg cools things down, with ice still on it.... It's a chilly 10 C in victoria beach while it's a beatiful 22 in gimli. A little weird, though, becuase there's not a lake breeze; the wind is from the south west, and victoria beach is south of lake winnipeg.

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    1. Actually a southwest wind would be off the lake in Victoria Beach. The town is basically surrounded by the lake.

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  9. Even warmer than what I was anticipating, all the way to 23.2°C as of 5 pm at the airport... easily the warmest day of the year and tying for 18th latest first 20°C of the year on record.

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    1. Yeah, it's a hell of a beatiful day out there. Just wish Mother's Day tomorrow will be this nice....

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  10. Not too bad today... although it will be a fairly cloudy day, we should manage to reach around 17-18°C. If we manage to see a few sunny breaks, maybe even a degree or two warmer.

    Consensus right now is for a major rain event across most of southern Manitoba with this incoming Colorado Low and associated inverted trough tomorrow into early Tuesday. Although still some uncertainties about location, I think the chance for a decent rainfall for Winnipeg is higher than the last system last week... with 15+ mm not out of the question by Tuesday night.

    Tuesday is still a question mark though. NAM is certainly most agressive with a slower and further west track of the Colorado Low, giving southern Manitoba wrap-around precipitation, perhaps even mixing with snow at times. Other models less aggressive and bring the system much further northeast, giving us just a cloudy day... Will be clearer tomorrow.

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    1. NAM really tamed in the latest update for Tuesday, now following more the other models. More and more looking like a tonight to early Tuesday rain event right now.

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  11. Looks like we will manage to get some sun this afternoon which will help to push things close to 20°C for a high... maybe another 20°C day? Time will tell..

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  12. Incredible thermal boundary in the RRV at this time... 21°C in Winnipeg, 17°C in Starbuck but just a measly 7°C in Portage and 9°C in Morden at this hour.

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  13. High of 21.1°C in Winnipeg this afternoon... hopefully you got to enjoy the last few days of warmth! Front has passed through with plummeting temperatures in the last couple hours so the beautiful days are over for now.

    Looks like a soaker tomorrow through to early Tuesday... 15-30 mm not out of the question at this point by Tuesday afternoon. Thanks for voting in the poll though! Average vote so far is 23.5 mm which I think is reasonable.

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  14. We're seeing a slightly delayed start to the rain this morning with rain finally pushing in mid morning. Unfortunately, still not a clear-cut forecast for today and tonight. Looks like Winnipeg could end right on the edge of things late in the day today. Nonetheless, 15-25 mm looks likely by tomorrow morning. Average vote in the poll is 33 mm.. I think that's going to be too high but we'll see.

    A chance of pop-up showers and flurries possible tomorrow afternoon and again on Wednesday thanks to very cold air aloft for this time of year moving in, making things a little unstable. We should see a few sunny breaks tomorrow as well, but generally it will be quite cloudy. More sun on Wednesday than tomorrow.

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  15. I am not liking how close to the edge Winnipeg is even as the rain is pushing north.... This certainly could turn into another miss of a system... Should've seen it coming! We'll see how it goes this afternoon, certainly not even close to over yet.

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    1. As of noon, looks like a general 2-5 mm so far today south and east of Winnipeg. Just a measly 0.5 mm in Charleswood, 0.2 mm at the airport and 1.5 mm here in south St Vital. The rain is just struggling to push westward so far.

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  16. BIG bust in rainfall forecasts for today in Winnipeg... all thanks to the deformation zone being literally just kilometres further east than expected (i.e. we just got grazed by the ''rain shield'' all day). Just over 4 mm here in south St Vital so far, but just around 1 mm in western parts of the city. Higher amounts of 5-15 mm so far east and south of the city, including:

    Marchand 12.4 mm
    Letellier 10.6 mm
    Beausejour 8.8 mm
    Morris 7.0 mm
    Steinbach 6.6 mm (as of 4 pm)
    (according to Manitoba Agriculture)

    We should continue to see showers this evening so a few more mm possible in Winnipeg, another 5-15 mm to our east.

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    1. I knew there was a reason that 2-5 looked so attractive to half of the first 4 voters. Same old story except the Perimeter Shields seems to be a little further east, south,west or north. Take your pick this year..

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  17. 9 mm here in south St Vital today... just 4 mm in Charleswood and around 3 mm at the airport... shouldn't get a whole lot more tonight... so overall, pretty much ALL forecasts were a big bust for today.

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