Sunday 24 August 2014

Thunderstorm Potential Today; October-Like Tomorrow

     Thunderstorms did not materialize in the RRV and southeastern Manitoba overnight. However, widespread rains still managed to dump some decent rainfall totals. In Winnipeg, generally 15-25 mm of rain fell from yesterday evening to 9 am this morning, including:

South St Vital 21.8 mm
Norwood 21 mm (via Brad)
Charleswood 20.8 mm
Winnipeg Airport 18-19 mm

      Winnipeg actually ended up on the lower end of things as most of the RRV and southeastern Manitoba actually got more. Generally, 25-45 mm fell in the remainder of the RRV and in southeastern Mantioba. Steinbach, Morden and Somerset have received some of the highest totals with 43.1 mm, 41 mm and 44.0 mm respectively, since yesterday (according to Manitoba Agriculture and Environment Canada).

     Highest totals so far have been in southwestern Manitoba and in the Interlake. Generally 40-50 mm has fallen in the Interlake in just the past 9 hours. Even higher amounts of 45-65 mm have already fallen in extreme southwestern Manitoba, west and southwest of Brandon:

Reston 63.6 mm
Pierson 62.2 mm
Melita 54 mm
Bede 52.8 mm
Virden 46.1 mm
Deloraine 42.6 mm

     Rain will taper off later this morning for the RRV. As the centre of low pressure and a cold front swing through this afternoon and evening, thunderstorms may develop. Some of these may be strong with hail, strong winds and funnel clouds possible. However, severe potential is contingent on some sunshine in southern Manitoba today. There is some clearing moving in from North Dakota this morning, but it's still hard to say if this will fill up with cloud later on. Depending on how much sun we can get, severe thunderstorms will be possible in the RRV and southeastern Manitoba. It will also be quite humid this afternoon with dewpoints in the low 20's, forcing temperatures into the mid 20's for some.

     MUCH colder tomorrow behind the system. Temperatures will remain steady in the low teens. This, combined with breezy west-northwest winds and shower activity, will make tomorrow feel more like October.

     Warming up later in the week with highs in the high teens Tuesday, low 20's on Wednesday and even warmer for the end of the week.

33 comments:

  1. The warmer conditions to end the month will likely spare us from a below normal August. It's looking likely at this point that August will be our first warmer than normal month since September last year!

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  2. Well, the sun is breaking through. We'll see how much of it we get through this afternoon. Could become quite an afternoon if we see enough sunshine.

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  3. Tough forecast today still... Yes, we've got some sunny breaks scattered here and there, but are they enough? I'm holding off on a slight severe risk for now due to the concern that severe activity may not be very widespread.

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  4. E.C. has just issued a Severe Thunderstorm Watch which includes Winnipeg.

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  5. I've issued a slight severe risk for the RRV and southeastern Manitoba, with hesitation. We'll see how things go, but I'm just concerned that severe activity wont be very widespread. Funnel clouds and tornadoes are a possibility today, along with flooding rains and strong winds. Large hail is possible, but a lesser threat. Best risk for Winnipeg is mid afternoon through to the early evening.

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  6. Clearing is now spreading through the RRV... Thunderstorm risk looking better and better as the afternoon wears on.

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  7. Cells starting to pop over Pilot mound area into SW RRV near the triple point. I'm thinking best bet for possible severe storms will be mainly over southern RRV and SE MB, but there's a chance storms could make it into Winnipeg based on storm motion and upper flow. Warm sector however still looking pretty murky for us..

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    1. Sure having a hard time so far. Not even getting any lightning detected. Hopefully things start getting going soon.

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  8. Lightning is now being detected near the triple point. I'm thinking cells should start to explode over the next 1 hour or so. But certainly not a guarantee.

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  9. Jj you think we'll make it storewise this evening?

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  10. Really warming up here now....26 C now at YWG with a dewpoint of 21C. Looks like we'll see a little more sunshine in the next little bit.

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  11. Lots of stuff trying to go up all across south-central and southeastern Manitoba at this time. So far, things are still having a hard time getting going. Mike, risk continues through the early evening for Winnipeg.

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  12. By the way, grand total here in south St Vital with last night's rain was 24.6 mm. This afternoon, we're also coming close to a dewpoint record... old record is 23.0°C set just last year. I don't think we'll be breaking that record, but we're not too far.

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  13. Looks like today is becoming yet another major too hyped up bust. Reality is as of now nothing has fired up and it doesn't look like anything will either at this point. As we are late in the season we have less daylight meaning daytime heating is lost sooner, so if nothing fires up in the next hour or so, it will go down as yet another disappointing setup blowing up in smoke.

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    1. Should have trusted my initial instinct in not issuing that slight risk. Nonetheless, still a line of storms appears to be developing to our south, will have to watch how that evolves.

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  14. Looks like a line of storms is trying to iniate southwest of of Winnipeg but really struggling to do so. Now we have the sunshine but too little too late. Would have needed that earlier today.

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  15. There sure are some nice towers with embedded anvils going up west and southwest of Winnipeg.

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  16. Clouds sure darkening rapidly to our west and southwest but it does not appear to be mounting into anything. Wow.

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  17. In my opinion the severe weather threat is over and probably theoritically never really existed today because of the lack of sunshine. Suspect that E.C. will drop the watch in the next hour or so as it really does not appear that storms will fire.

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  18. The line just to the south of Winnipeg is having trouble organising. Towers are too skinny so far. Storm west of Winnipeg is more impressive for sure, could clip the northwest Perimeter.

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  19. As expected the watch has been dropped for us. Severe weather threat over. Although in my opinion, it never existed. Today just did not seem a like a day conducive for storms. The lack of storms overnight last night should have been the signal.

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  20. Went with Matt to check out the storm to the northwest of the city. Considering Winnipeg got nothing as usual, it was worth it. Not much lightning with today's storms, but there were some cloud-to-ground strikes. The main story with the storms northwest of the city was actually the clouds. Extreme turbulence could be seen at the back edge of the storm, some clouds rising, others descending, others moving northward, others southward. Was actually quite interesting!

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  21. An extremely lousy day today with scattered showers and drizzle, breezy west-northwest winds and temperatures remaining steady near 11-12°C.... Much more typical of October.

    Cool conditions continue tomorrow with a high around 18°C. There will be some sun, but cloud might win over sunshine at times. Cool next couple nights with lows in the mid to high single digits.

    Warming up by Wednesday with a high around 23-24°C, 26-28°C Thursday. Remaining in the 20's for Friday, but a cold front will be passing through which could bring some shower and storm activity. Cooler for Saturday behind the front, but not as cool as today's cool down. It is too early to say what will occur after Saturday.

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    1. Will have some rainfall totals from this system this evening.

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    2. Also forgot to mention that we could even see some lake-effect showers and drizzle coming off Lake Manitoba today and tonight. A sign of the times!

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  22. Today is about as lousy as it gets for this time of year. Unfortunately thew news isn't a whole lot better down the road. Although it will warmup by midweek, don't expect it to be a long term thing. September does not look warm at this point. As 2014 would have it, after a month reprieve from cooler weather, it looks like the below normal regime will once come in and control the show as we head towards fall, although it shouldn't be as severe as earlier this year, at least we hope not.

    As for the El Nino, well that news is less encouraging now as it's now forecasted to be a weak El Nino, so wether or not we see a milder winter is up in the air at this point.

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  23. The way things are shaping up, 2014 could very well go down as one of the lousiest ever weather years.

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  24. Jj How often do we have frost in August and when was the last year?

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    1. We haven't dropped below zero in Winnipeg in August since 1910... so frost in August is extremely rare. The closest we've gotten so far was a low of 0.0°C on August 20, 2004. The earliest was August 24, 1885 with a low of -0.6°C.

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    2. Thanks jj I thought we had frost a few years ago but not.

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    3. 2004 was the summer of torrential rainfall in the Central Manitoba prairies. With water standing in fields and ditches for miles west of the city. I thought the rain we have had for the last ten days and the rain in august of 2004 would keep the temp warmer but apparently the opposite is true see melita rain and 0.5 C temp

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  25. Another cold one today. Lake-effect cloud and showers overnight helped keep our temperatures a couple degrees warmer than they could have dropped to. Some very chilly lows in southwestern Manitoba including Brandon at 3°C. All the way down to 1.6°C in Grandview and about 0.5°C at the Melita Manitoba Agriculture station. We'll likely remain under more cloud than sun today in Winnipeg with highs only around 17°C or so. Another chilly night tonight in the single digits.

    Sun comes back for tomorrow and Thursday with highs of 23-24°C tomorrow and 27-28°C on Thursday. Note that the Canadian model is not as warm for Thursday. Cold front passes through on Friday with a chance of showers and perhaps a thunderstorm. That sunny forecast from EC is a little too optimistic. However, the front may pass through too early in the day for a decent storm chance. Models show it passing through already by midday, so the best risk for storms may end up to our east.

    After that, all I can say is that conditions look quite variable, which is typical of a more fall-like pattern... Lots of ups and downs. Cooler for Saturday but warming back up for the beginning of the week. Possibly another cool down mid-week before warming up again.

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