Thursday 25 April 2013

Welcome Spring!

     Before I get to the forecast, I must note that the airport reached a milestone yesterday. It FINALLY reached +5°C yesterday with a high of 5.5°C. That makes April 24, 2013 the latest date on record to hit the first +5°C of the year. What's so impressive about this record is the fact we beat the old record by more than a week. The previous latest date to hit the first +5°C of the year was April 15, 1950.

     Now, yesterday was just a taste of what's to come. A long-awaited pattern change is beginning to take shape as we speak. The jet stream, which has been diving way to our south in the last several weeks will finally move northwards and become more zonal. This will allow clipper systems from Alberta to move to our north instead of to our south, putting us into the warmer side of these systems. This change begins today with increasing southerly winds this afternoon. They are expected to be sustained near 30 km/h with gusts up to 50 km/h at times possible. These winds will lighten a little tonight, but still remain breezy which will keep temperatures a little higher tonight. Lows between -2°C and 1°C are expected across southern Manitoba.

Model image courtesy of A Weather Moment's Model Viewer

     Much warmer air aloft will be moving in from the southwest over the next couple days, but it's hard to say just how much the record snow pack over the eastern Prairies and North Dakota will impact the temperature climb at the surface. As a result, daytime highs are a little more unpredictable than usual between today and Sunday. Cloud cover will also hinder the temperature rise on the weekend.

     Tomorrow, it will be a close call for Winnipeg to hit the first 10°C of the year. I'm expecting a high between 9 and 11°C for the city.

     Saturday is when things get interesting and even a little unknown. With such warm air aloft, it will difficult for the snow pack to put a severe dent on the temperature climb. However, cloud cover could slow the climb. Nonetheless, I'm expecting a high between 15 and 17°C in Winnipeg right now, but it could be warmer if we get more sunshine than anticipated. Dewpoint is the big question mark. NAM brings in fantasy-like surface moisture with dewpoints in the mid teens, unusually high for this time of year.

     With a trough of low pressure and an associated cold front Saturday night, showers are expected, and perhaps even some rumbles of thunder if we can get as much moisture as the NAM suggests. For now, I'm considering the thunderstorm threat as very small, but I will keep an eye out.

     In the longer-long range, another clipper system is expected Monday night. For now, it looks like precipitation will remain as rain for us here in Winnipeg. Some models give us 10-20 mm while others give just a couple mm,  therefore it will have to be watched. Any rain is unwelcomed right now. Behind that system, a cool down is expected, but not nearly as long-lived as what we've been seeing lately.


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Source of the image of flowers at the top of this page here.

16 comments:

  1. I must also note that today marks the 47th consecutive day with below normal temperatures. Truly exceptional.

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  2. Airport is just struggling to rise above the 5°C barrier once again today. I'm sure that stiff south wind up the valley is not helping, and also the cloud cover which apparently has been in the northern parts of the city today. I can't speak for that part of the city, but here in the south end it's been much sunnier; all the way to +6°C at my place.

    I hope this is not a bad sign of things to come in the next few days...

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  3. If we manage to reach 10°C tomorrow (which looks quite likely) it would tie for second latest on record to hit +10°C for the first time in a year. It would be tied with 1904 when we didn't hit +10°C until April 25 (note: 1904 was a leap year therefore April 25 that year was the 116th day of the year whereas this year, April 26 is the 116th day of the year. That's why it ties).

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  4. Looks like The Weather Network's new website no longer has lightning tracker. I'll have to remove that link from my thundercast page.. but I have found a new lightning tracker that I find interesting which I'll use to replace TWN's. Here it is for those who are interested:

    http://www.lightningmaps.org/blitzortung/america/index.php?lang=fr&

    I just found this website, therefore I'm not certain about the accuracy just yet.. Will have to wait until thunderstorms occur here to verify that.

    However, what I really like about this one is that it archives the lightning data, and has been doing so since 2012.

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  5. Only past 9 AM and we're already warmer than yesterday's high. We'll likely reach 10°C easy today. I'm raising my predicted range for today's high in Winnipeg to 11 to 13°C.

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  6. Based on how today is going, 15°C will be an easy target tomorrow if we get enough sunshine. Temperatures aloft look at least 5 degrees warmer tomorrow.

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  7. Looks like the answer to the snowcover poll I made earlier in the month will be April 26-30. Only a few pesky remnant drifts at my place right now therefore snow depth still at a trace today. The way things are melting, it will probably be at 0 cm tomorrow! Finally time to do some yard cleaning!

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  8. High of 14.8°C at my place today. Also 14.4°C in Charleswood and 15.4°C in Whyte Ridge.

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  9. A few scattered sprinkles out there this morning across southern Manitoba.. all elevated in nature. Not seeing any lightning.

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  10. Will be interesting to see today's high. Air aloft is very warm today which could equate to highs near 20°C if we get enough sunshine.
    Looking at visible satellite, it does look like there's clearing behind this area of cloud. That clearing could reach us by late morning or noon. However, more cloud over Saskatchewan is poised to move in later this afternoon.

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  11. Some mammatus going over downtown this morning:

    https://twitter.com/robsobs/status/328167333073911808/photo/1

    Still haven't seen a single lightning strike anywhere in Manitoba this morning.

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  12. Seed pods are finally coming out on my maple tree now... an astonishing month and a half later than last year when they started coming out in mid March! A sure sign that spring is in full swing.

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  13. 16°C at my place right now. From what I'm seeing, that's the warmest in the city right now.

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  14. Only 15°C at the airport as of 3 pm.. Hmm 20°C is not going to happen this time 'round, despite the sunshine this afternoon. Only problem I can think of is that stiff south wind up the valley coming from the more snow covered areas to our south/southwest.

    Will keep an eye out for Monday; our next shot at some thundershowers. Not a major threat, but a few rumbles look possible. Will have a new post tomorrow.

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  15. NAM's prediction over the last few days for mid teens dewpoints today was a major bust for that model. Dewpoints have only reached the mid single digits here today and as high as 9°C in Sprague. A few dews in North Dakota near 10°C but one has to go all the way down to Missouri to find some dewpoints in the mid teens today:

    http://puu.sh/2IpF5

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  16. 17.3°C at my place so far today, warmest day of the year so far.

    A note, I'm redesigning the record books page and hope to finish soon.

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