Wednesday 14 August 2013

Summer's Returned!

     A pattern change is finally in the works. For the past several weeks, the jet stream has been dominated by a trough in northern Ontario and a ridge over western Canada. As a result, we in southern Manitoba have been locked in a cool north/northwesterly flow resulting in nearly a month of below normal temperatures in Winnipeg. Since July 18, Winnipeg has only maxed out at 25.2°C... in a period where normal highs are generally between 26 and 27°C. In this period (July 18 to Aug 13), the average high has been 22.3°C, a good 4 degrees below normal for the period. Lows have averaged 9.1°C, also a good 4 degrees below normal for the period.

     Over the next few days this will be changing as things begin to shift eastward. Areas that have been hot for the past few weeks will now cool down a bit and areas that have been cold will finally warm up. For the Winnipeg area, highs in the mid 20's are expected today, with temperatures reaching 30°C by Friday. Saturday at this point looks like a scorcher as temperatures rise to the 32 to 34°C range along with moderate to high humidity. Humidex values will likely reach the high 30's and potentially close to 40.

     Chances for showers and thunderstorms return to end the weekend. Seasonal to above seasonal temperatures are expected to continue next week.

35 comments:

  1. In case you didn't see my answer to your question Walter, here it is below.. I'm not sure why sometimes when I make new posts, only the 1 post is shown on the homepage.

    ''It's the 'urban heat island' effect. The darker surfaces of the downtown area (concrete, asphalt, etc..) absorb more heat during the day than in areas where there is more vegetation. That heat is released at night keeping temperatures warmer. If you're interested, here's a good video talking about this effect:

    http://www.youtube.com/watch?v=t-sXHl3l-rM
    ''

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    1. Thanks for the video, I liked it a lot.

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  2. The NAM are really pushing saturdays temps with a max of 35.2 at 4:00 PM!

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  3. It's bud the spud from the bright red mud
    Rollin' down the Highway smiling-
    The Spuds are big on the back of Bud's rig
    And they're from Prince Edward Island they're from Prince Edward Island

    Now from Charlottetown or from Summerside
    They load him down for the big long ride
    He jumps in the cab and he's off with the pride Sobagos
    He's gotta catch the boat to make Tormentine & he heads up that old New Brunswick line
    Through Montreal he comes just a flyin with another big load a potatoes.

    It's bud the spud from the bright red mud
    Rollin' down the Highway smiling-
    The Spuds are big on the back of Bud's rig
    And they're from Prince Edward Island they're from Prince Edward Island

    Now the Ontario Provincial Police don't think mucha Bud...
    Yeah the cops a been lookin for the son of a gun
    That's been rippin the tar off the 401-
    They know the name on the truck shines up in the sun-"Green Gables."
    But he hits Toronto and it's 7 O'Clock when he backs er up agin the terminal dock.
    And the boys gather round just to hear him talk
    About another big load a potatoes!

    It's bud the spud from the bright red mud
    Rollin' down the Highway smiling-
    The Spuds are big on the back of Bud's rig
    And they're from Prince Edward Island they're from Prince Edward Island

    Now I know a lot of people from east to west
    That like the spuds from the island best.
    Cause they'll stand up to the hardest test-right on the table.
    So when ya see that big truck rollin by- wave yer hand or kinda wink yer eye,
    Cause that's Bud the Spud from old PEI, with another big load a potatoes!

    It's bud the spud from the bright red mud
    Rollin' down the Highway smiling-
    Slow-because he's got another big load,
    Of the best dog gone potatoes that's ever been growed
    And they're from Prince Edward Island They're from Prince Edward Island

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  4. Saturday's severe weather potential looks quite interesting at this point. Perhaps a chase day in Southern Manitoba? We'll see.

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    1. Cloud cover and capping are my biggest concerns with Saturday, especially the capping part because it is expected to be fairly strong. Other than those 2 potential inhibitors, the other ingredients look interesting.

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    2. Capping is my number one concern at this point as well. There will be a large layer of very steep lapse rates aloft, but that layer will be associated with very warm air. In order to break the cap it looks like surface temperatures in the low to mid thirties will be necessary. Since upper forcing is weak, if convective temperatures are not reached there's probably a strong chance that nothing will happen. Hopefully things "cool down" a bit before Saturday!

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  5. Mike SouthMBWeatherAugust 15, 2013 4:16 pm

    JJ did you see the latest NAM Model run? CAPES are in the 2000 to 4000J/Kg range, with a weak cap. Severe Weather Outbreak?

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    1. Mike SouthMBWeatherAugust 15, 2013 4:17 pm

      Oops forgot to add that it will occur Sunday...

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    2. I think our best shot will be late Saturday into Saturday night here in Winnipeg.. I like how the NAM brings in a surface low into southern Manitoba tomorrow night.

      Yes instability is expected to be extreme Sunday, but you still need a trigger. Best risk on Sunday I think will be to our north in Central Manitoba.. but it's still to early to draw to conclusions though.

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  6. Seems to me E.C's a little out to lunch with the 28C forecast for today and tomorrow. Most model guidance is still indicating temps in the thirties today and tomorrow. It's looking like the severe weather potential for tomorrow evening and night is diminishing at least foe here in Winnipeg/RRV. Too much capping.

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  7. Temperature forecast is tough today. We got lots of cloud from a complex of elevated storms in the Interlake and east of Riding Mountain this morning. Behind it there is still a lot of high cloud so it certainly doesn't look like a full sunny afternoon.. but it might be thin enough to still let in a fair amount of sunshine. If this were a full sunny day, we would have been talking about highs in the mid 30's today.

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  8. Complicated forecast for thunderstorms today and tonight. Storms may not form until very late in the day (later in the evening) due to the strong capping situation this afternoon. Severe weather is still possible with those overnight, with large hail and damaging winds possible.
    Note that I wont be able to update from late this morning to early evening.

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  9. Thunderstorms still possible tonight... but it's unfortunately still quite uncertain if anything big will come of the setup. Lots of dry air above ground in the RRV this evening (as seen in a sounding sent at uofm this evening) which isn't good for storms, but models have more moisture moving in later tonight which hopefully comes true. Will be an interesting night... Either you will wake up from storms or we don't get a drop.

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  10. Thunderstorms certainly possible tonight but I don't think severe weather will be in the cards however. Severe weather hasn't really occured today even in the less capped atmosphere in the Interlake and north of Dauphin. As mentioned too much dry air above the surface in the area at the moment and not so sure that will change much overnight but we'll see. This certainly was nowhere near as hot and as humid of a day as to what was expected. Actually yesterday was hotter than today. E.C. called it right yesterday when they had dropped the forecast high to 28C for today but then they brought it back up to 30C which didn't materialized today due to the cirrus shield that was over us much of the day but either way it's still very much summerlike tonight.

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    1. Well it's sure being yet another dissapointed tonight with nothing getting organised yet. Still a few more hours left... but my optimism is at a minimum. We'll see what happens...

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  11. Here come the storms! Just 6 hours late!

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    1. Severe thunderstorm warning out for Winnipeg.. main threats will be large hail and flooding rains. Just goes to show how explosive the environment is when we're getting this at 8-11 am in the RRV!

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  12. 25 mm of rain in Charleswood in just 15-20 minutes.

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  13. Forecasts wont be updated today. Sorry about that! I was enjoying the storms this morning and I can't update this afternoon!

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  14. JJ, do you think we'll see more storm development later today or this it for the day?

    Anon

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    1. Front will push to our east so best threat pushes that way today. Could be some storms in southwestern Manitoba today. Risk not very high in Winnipeg, but there is a small risk later today.

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    2. Brandon getting pelted at this hour. Storms will move eastward.. will be interseting to see if we can get something out of it here in Winnipeg.

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  15. Well, if you go by E.C's forecast there will no thunderstorms in Winnipeg this evening. Storms are not forecasted for Winnipeg although i'm not sure about that forecast at this point but we'll see. Sure is very humid right now and by the looks of things quite unstable.

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    1. Yeah I think there should at least be a chance mentioned.

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  16. I have feeling E.C. may very well adjust that forecast over the next while. I think the chance for storms here this evening is quite good.

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    1. Lots of boundaries left over from this morning's complex too, so additional pop ups are also possible, albeit less of a risk then the storms near Brandon.

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  17. Rainfall amounts from the storms earlier today:

    St. Adolphe 53.6 mm
    Starbuck 41.4 mm
    Portage 15.3 mm
    Selkirk 14.4 mm

    In Winnipeg:
    Charleswood 41.7 mm
    Downtown (u of w) 37.3 mm
    Whyte Ridge 21.4 mm
    River Park South 9.3 mm

    2013, the year of the freak rainstorms in Charleswood!

    We really missed out in south St Vital with just 9.3 mm here at my place. However, I measured hail up to 1.8 cm in diameter, or about dime sized.

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  18. Well, it does look like E.C's forecast was good after all. Thunderstorms not that likely tonight as storms are diving southeast towards the american border.

    On another note, it looks like tomorrow is gonna be an absolute scorcher. 33C to 35C quite possible as we see alot more sunshine than on the weekend and a favorable southwesterly breeze could very well bring us the hottest day of the year.

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    1. But we did get rain which wasn't given a chance. 0.5 mm here in south St Vital.

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  19. Speaking of which (the rain this evening), I wonder if there will be some fog tonight and/or to start tomorrow. We'll see. Alraedy looks like a mist in the air this evening.

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    1. Although there was fog reported at the airport overnight, it never got thick. Looking at visible satellite, it looks like there is fog in the southern RRV and southeastern Manitoba.

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  20. JJ, what is the thinking it'lle get today today.

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    1. At the moment, I'm thinking 32 to 33°C as a high today; 34°C looks like a stretch at the moment. But we'll have to see how much help the southwesterly winds are later this afternoon.

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