After 4 weeks of below normal temperatures, a major shift in the upper atmospheric weather pattern will finally signal a return to more typical summerlike weather over southern MB. The weather pattern over the past month has been dominated by a persistent upper trough over Hudson Bay into the Great Lakes that has resulted in a prolonged period of below normal temperatures over the eastern prairies into Ontario. Including today (August 14th), Winnipeg will have gone 27 consecutive days below normal, at a time when the hottest weather of the season often occurs. During this stretch, Winnipeg has hit the 25C mark only twice, with a maximum of only 25.2C. The normal high during this period is 26C.
The below normal streak however will be coming to end starting tomorrow. The persistent upper trough over central Canada will finally be shifting east and replaced by an upper ridge over the Prairies, allowing warmer air from western Canada to finally spread eastward. High temperatures in southern MB will climb from the mid 20s today to the 30C mark by Friday, with 30c+ weather expected over the weekend into next week. Things may start getting a little more unsettled as well Sunday into Monday as a weak impulse passes though southern MB, tapping warm and more humid air and triggering scattered thunderstorms. Above normal temperatures however are expected to persist much of next week, great news for those who weren't quite ready to say goodbye to the summer of 2013 just yet.
In case you're wondering where our summer was for the past month, it's been vacationing in the BC interior. Ashcroft BC (west of Kamloops) hit 32C today for their 17th straight day of 30C or more. Over the past 28 days since July 18th, Ashcroft has failed to hit 30C just once with a high of 27.8C on July 28. Their average high in August so far has been a blistering 34C. Time to share the heat BC...ReplyDelete
It seems to me that we've had an excessively large proportion of years where B.C has had hotter than normal summers. Whereas out here, we've had equal proportions of cold summers and hot summers. I can't remember the last time interior BC had a cold summer (even by their standards).ReplyDelete
Will be interesting to see how hot we get the next few days, especially Saturday. Friday looks like our first 30C day in 6 weeks when we hit 30.7C on July 4th. NAM guidance showing 925 mb temps of 25C by late Friday over the RRV, which would translate to a high of about 31C in Winnipeg. In addition, winds will be a little stronger Friday as southerly winds accelerate up through the RRV with speeds of 30 to 40 km/h by afternoon. The brisk southerly winds will persist Friday night, so it should be a nice balmy evening for outdoor activities. Saturday looks even warmer as 925 mb temps climb to 27C, so highs of 33C possible with enough sunshine along with gusty south winds again. Hints of possible tstorm activity over RRV and Winnipeg by Sunday, but too early to be more specific.ReplyDelete
The forecast keeps changing on EC. Yesterday they had us up to 35 (!) on Saturday... but I see now they've dropped it all the way to 28, which is disappointing. Don't get me wrong, 28 is still plenty hot, I was just looking forward to it being the hottest day of the year. Is that new Saturday forecast to be believed or is 30-33 still quite likely tomorrow?ReplyDelete
Those highs of 28C today and Saturday seem a little underdone compared to other guidance. NAM and GFS models are showing highs of 31-32C for Winnipeg today and Saturday, while Euro is 28C today and 30C Saturday. Based on progged 925 temps, I would think we should see 30-31C today and 32-33C Saturday. There are indications that some higher level cloud will move in Saturday which may limit our heating somewhat, but I think we still have a good shot of low 30s Saturday. Note that both days will see gusty south winds of 30 to 50 km/h by afternoon, so it won't feel as hot as it would have with light winds and a strong sun. But definitely more summerlike than we've seen in awhile. Will likely need the AC for the first time since mid July!
EC forecast highs have been bumped up to 30C today and Saturday. Seems more reasonable.ReplyDelete
An official 30C day here at YWG airport today with a max temperature of 30.0C, first 30C day since July 4th. Tomorrow has the potential to be 2 or 3 degrees warmer, but increasing high clouds will limit max heating. Still looks like another 30-31C day, possibly 33C if clouds are thin enough.ReplyDelete
Elevated tstorms pushing through the Interlake this morning and weakening.. Winnipeg will get brushed with some cloud on the southern edge of that system this morning, but bulk of activty should stay north of the city. Otherwise, another breezy and very warm day shaping up today with high temperatures in the low 30s this afternoon.ReplyDelete
Rob- Why did you switch back to the CBC forecast graphic? It's wrong again, showing 22C for Sunday, 17 for Monday, and so on. CTV's still look good however. (Not endorsing one or the other, just wondering why you went back to the bad one).ReplyDelete
Wow.. I can't believe that. It looked fine this morning. I was hoping CBC had fixed the weekend problem, but I guess not. I switched back to CBC because the CTV forecast graphic would have wrong dates on it at times. During the week, I find the CBC graphic is fine.. but I don't know what happens on the weekend. Totally out to lunch. They should just leave the forecast graphic from Friday and let it run all weekend. It would be better than what they do now.ReplyDelete
Of course, my preference would be to use an EC graphic, but they don't have a nice 7 day forecast graphic I can use.
Rob, do you think we'll see thunderstorms possibly severe here in Winnipeg tonight?ReplyDelete
I think we have a chance of seeing some nocturnal tstorms here after midnight.. although I don't think they'll be severe. We had some elevated storms last night through the interlake, and we could have a repeat tonight only a little further south, like along the TCH corridor. But nocturnal storms are notoriously difficult to predict.. as they can pop up just about anywhere and may not affect your locality. So the potential is there for some nocturnal storms tonight in the RRV, but whether they affect Winnipeg is too tough to say at this point.ReplyDelete
Well, I don't think we will see 30C here in Winnipeg today. So much for that hot day that today was supposed to be. It was actually considerably hotter yesterday.ReplyDelete
Yeah, that cirrus shield that the models were hinting at has come in and slowed down the heating. We're steady at 26-27C, when we easily could have been in the low 30s today given enough sunshine. We still have a chance at 30C if the clouds thin out soon, but time's running out.ReplyDelete
Note that it's up to 29C in places like Carman and Melita where clouds are thinner.
Re The CBC WX Graphic - looks more like last weeks forecast than this week's IMO.ReplyDelete
I changed graphic back to CTV.. couldn't live with that high of 17 for Monday. CBC needs to look into why the weekend graphic defaults to something old.ReplyDelete
A line of convection is starting to form west of Brandon late this evening.. whether or not it translates into some overnight storms for us remains to be seen. But it would be nice to see and hear a decent thunderstorm around here.. I can't remember the last time we had one here!ReplyDelete
I have to admit, yesterday was a disappointment. Temperatures didn't even hit 30, let alone mid-30s like they were initially predicting. The day before (the 16th) was actually a significantly warmer, nicer day in fact. Nothing happened on the thunderstorm front either, despite 60% chance of nocturnal storms according to EC, maybe 'cause things didn't heat up like they were expecting.ReplyDelete
That said the clouds are suddenly looking very dark here...ReplyDelete
EC sleeping in? Fast mowing storm to the north and west of the city, blacker than heck and radio full of static. No watch no warning go figure.ReplyDelete
City of WinnipegReplyDelete
9:53 AM CDT Sunday 18 August 2013
Severe thunderstorm warning for
City of Winnipeg issued
At 9:55 AM CDT, meteorologists are tracking a line of severe thunderstorms capable of producing large hail, damaging winds and heavy downpours. Nickel to quarter size hail and heavy downpours of 25 mm or more are possible with this line of storms.
Take cover, if threatening weather approaches.
Strong wind gusts and hail can damage property and cause injuries. Local downpours can cause flash floods.
Avoid driving through water on roads. Even shallow fast moving water across a road can sweep a vehicle away.
Remember, severe thunderstorms can produce tornadoes.
In Canada, lightning kills up to 10 people every year. Remember, when thunder roars, go indoors.
Environment Canada continues to monitor the situation closely. Please continue to monitor your local media or Weatheradio for further updates. If you would like to report severe weather, you can call 1-800-239-0484 or send an email to email@example.com.
Updated or ended by 11:00 AM CDT.
Speak of the devil Evan, now we've got a *good* thunderstorm for once. Woke me up.ReplyDelete
No kidding! That was a very nice morning surprise. The hail up here (northwest Winnipeg) was mostly nickel- or dime-sized, I think, but some of the larger bits looked quarter-sized to me. *Booming* thunder and great cloud-to-ground lightning. Best thunderstorm we've had in this part of the city all summer.ReplyDelete
Rob, I see that you were on CJOB this morning. At least on the website!!ReplyDelete
We only around 12mm in River Park South.ReplyDelete
18mm here in fort garry, with pea sized hailReplyDelete
31.4mm in Edgeland and no hail. Rained like a carwash at the Assiniboine zoo; no hail there either.ReplyDelete
Winnipeg's forecast for tonight calling for partly cloudy. Looking out west, I have a feeling that forecast will be changing!!ReplyDelete
Skies to the west do look a little threatening, however storms out west are diving to the southeast towards the US border, so Winnipeg should be safe from storms this evening. These storms were surface based with afternoon heating so they should die as the sun sets.ReplyDelete
Tomorrow looking like a scorcher. We should have plenty of sun (unlike the weekend), and a favourable southwest wind but not too strong. Airmass will be capped so thunderstorms not expected. 925 mb temps climb to 27C, so a high of 33C quite possible.. maybe even 34C if we get enough sun with humidex values approaching 40 by afternoon. Could be the hottest day of the year. Stay cool!
I saw that rainfall map of Sunday morning's storm you posted on Twitter. I told you it was the best storm of the season for this part of the city (northwest Winnipeg)! Around 50 mm of rain in my area according to that map, plus we had two separate waves of small hail. 65 mm just a bit further to my west.ReplyDelete
Yeah, that map was impressive. Really showed the variation in rainfall across the city, even though the line went through the whole city. NW really got it the worst, with lesser amounts to the southeast.ReplyDelete
Things picked up again south of the city with 54 mm in St Adolphe! Really shows the difficulty in trying to predict rainfall amounts with these convective storms.
For those who haven't seen the city rainfall map.. click on my name.
Rob I've noticed a descrepancy in the climate data on EC's website. To explain I have to give an example:ReplyDelete
When you look at the average mean tempearture for June 1988, there are 2 values given depending on where you look:
When you look at the daily data for the month, it shows an average monthly mean of 22.1°C:
However, when you look a the monthly data for the year, it shows an average monthly mean for June of 22.0°C:
So my question is: which is the correct value? 22.0°C or 22.1°C?
Oh I forgot to mention that this descrepancy happens a lot Rob. I'm not sure if you noticed it.. but I've noticed this in many years, and not just for average monthly temperatures, but also for total monthly rainfall, snowfall and precipitation.ReplyDelete
I think the monthly data is the official data for the monthly values.. as the daily values may have some rounding issues that lead to a slight discrepancy with the overall monthly totals/averages. This is especially true for data before 1975 when we went metric. All imperial measurements before 1975 have been converted to metric, but there can be slight discrepancies with monthly totals/averages due to rounding issues.