An active weather pattern is setting up over the southern Prairies this week, with locally severe thunderstorms likely over southern Alberta and southern Saskatchewan again later today into tonight. The remnants of that convective activity will spill into southwest Manitoba Thursday, with showers and thunderstorms expected to re-develop over southern MB including the Red River valley later Thursday into Thursday night. Some of these thunderstorms may be strong with heavy rain and frequent lightning, with the potential for some locally severe storms giving large hail and strong wind gusts. This activity is expected to push through southern MB by Friday morning, with additional thunderstorms possible later Friday especially over southeast MB and near the US border.
|Kenaston Blvd near Sterling Lyon Parkway last evening|
photo credit @tracyljk
A nearly stationary thunderstorm cell over southwestern parts of the city dumped torrential rain Thursday evening, with amounts of 50 to 75 mm reported within 2 hours. The heavy rains caused flash flooding on some major routes in Tuxedo and Charleswood and even flooded IKEA and Superstore buildings. See "A Weather Moment
" for additional details on this event.
At my station in Charleswood, I picked up 69 mm of rain between 720 and 920 pm. (see rain accumulation graph left) Heaviest rain was between 720 and 820 pm when 50 mm fell within one hour, with a peak rainfall intensity of 293 mm/hr at 7:39 pm according to my Davis Vantage Pro weather station. See City of Winnipeg rainfall map
that shows the localized nature of this extreme rainfall.
Yet another thunderstorm event to our west.ReplyDelete
The next few days better produce something here, or else there's going to be a lot of swearing amongst us storm lovers.
Could somebody wake up EC so they can start issuing Watches & WARNINGS in the SW of MB P L E A S E !!ReplyDelete
Gretna was the Canadian warmspot yesterday at 30.2C.ReplyDelete
At 9:00 PM Thursday, SpotWX is predicting 53.6 mm of rain. How credible is such a forecast event?ReplyDelete
My guess is that those storms in SW MB are not as strong as the radar suggests. Looks like they're weakening too.ReplyDelete
Box134 - The GEM Regional model and the SCRIBE both show that whack of rain this evening (over 50mm). But the Meteocode, which is the human-adjusted numbers behind the public text forecast, reduces that to 15-25 mm.ReplyDelete
In the FXCN01 CWAO weather discussion from EC (link here: ftp://tgftp.nws.noaa.gov/data/raw/fx/fxcn01.cwao..txt) they say "REG QPF MAX AMOUNTS FORECAST LOOK REASONABLE IN THUNDERSTORMS, BUT
LOOKS A BIT HIGH OVER SRN MB." So the forecasters are thinking that 50+mm is too much. I hope so, because my new grass seed will be washed away!
Thanks for that. One other thing I'm wondering about.... there are three different forecast periods using the same model, yet the forecasts don't seem to match up. Shouldn't they be the same?ReplyDelete
Box134 - Can you elaborate? Are you talking about the GEM models under Numerical Weather Models, or the SCRIBE under Nearest Station Forecasts?ReplyDelete
EC has dramatically backed off on the prospects for showers and thunderstorms tonight for Winnipeg.. now calling for only a 60% chance of precipitation for us. (RGEM this morning was giving Winnipeg 60 mm of rain tonight.. so we've gone from 60 mm to 60% POP!) This looks reasonable based on our capped thermal profile today, as well as energy-robbing debris cloud that has spread across southern MB today from convection south of the border. Models still insist that convection will fire up or move into SW Manitoba this evening and spread into the RRV tonight, so there's still a chance we'll see something here. Note that thunderstorms have developed late this afternoon over SE Saskatchewan where a thunderstorm watch is now in effect.ReplyDelete
So it's not a total bust yet.. but things will have to ramp up quickly over the next few hours for us to see anything here tonight. Hopefully we do get a decent storm tonight.. certainly feels like thunderstorm weather out there today!
Rob, what are the chances for severe weather this weekend?ReplyDelete
Also, do you think it's possible that we'll see our first 30C day sometime next week here in Winnipeg?
Rob, what has changed in the last 2 years that we simply don't get these severe weather events in Southern Manitoba anymore compared to prior to 2011?ReplyDelete
>> Anonymous said...Rob, what has changed in the last 2 years that we simply don't get these severe weather events in Southern Manitoba anymore compared to prior to 2011?ReplyDelete
It's possible that the past couple of years have seen more of a blocking pattern in the atmosphere which has resulted in more persistent patterns of certain weather.. (such as our prolonged heat in 2012, now our prolonged sub-normal run) Perhaps this has resulted in a concentrated area of more frequent severe weather in certain areas (such as Saskatchewan) while leaving other areas less active longer than normal (such as us)
But I'm just speculating. It could just be a cycle we're going through like with heat or drought.. and eventually things will get swing back to a more active pattern. But I really don't know..
Severe thunderstorm now in effect for Winnipeg and most of South MB. Storms exploding and trying to fight the cap just west and southwest of WinnipegReplyDelete
LOL. The 18Z run of the Regional GEM has 60+mm of rain for us overnight again. It's look to be triggering too far north, based on the current activity.ReplyDelete
And watches are out for a bit of the province. A severe thunderstorm watch was also put out by the SPC for the Fargo area, but not Grand Forks (but they've noted eastward expansion into MN).ReplyDelete
Already there are two strong cells moving slightly northwestward, but no warnings yet.
And that's our first rumble of thunder for the night!ReplyDelete
We've got our 2nd severe thunderstorm warning (in the city) for the year now. Main threat specified is flash flooding, and should be updated/ended by 9:20.ReplyDelete
Now THIS is what you call a downpour. Wouldn't be surprised if the Calgary area floods are spooking Winnipeggers.ReplyDelete
Well, for once Winnipeg is getting the only thundershower in the Red River valley. It sure isn't moving much, my street is a river. Looks like the GEM-REG got the latitude correct after all (or maybe got lucky).ReplyDelete
The XWG weighing gauge recorded 4.6 mm in the last hour, while the tipping bucket recorded 5.6 mm. Usually the tipping bucket records less, especially in heavier rain.ReplyDelete
Either way, there was much more rain south of the airport. 52mm at Robs?!
Odd indeed. We'll have to see what the two CoCoRaHS gauges in the city got.ReplyDelete
Well what do you know.. we got that 60 mm after all!! (well, I did anyways) Storm total of 62 mm here at my place, with rain finally easing up now. Roads flooded in Tuxedo/Charleswood area.ReplyDelete
In Charleswood here too Rob. I believe the 62mm! Our backyard looks like a lake and we have water in our basement. Ditches are full here. I hope thats the end of it for the night.ReplyDelete
Grand total here of 69 mm from my backyard weather station (verified with 70 mm from my standard gauge)ReplyDelete
Several roads flooded in Tuxedo/Charleswood area with many ditches full or overflowing. Kenaston underpass closed due to flooding. Even IKEA has flooded!
very little rain up here in River bend. anyone have measured totals up this way to report?ReplyDelete
Wow only 10mm in South St. Vital (River Park South(ReplyDelete
Only 8 mm in Island Lakes this evening.ReplyDelete
By the way, that 69 mm fell in 2 hours between 720 and 920 pm. 50 mm of that fell within the first hour up to 820 pm. Peak rainfall rate was 293 mm/hr at 7:40 pm. Rain was literally gushing down. No hail or major winds. Hardly any lightning either. Just a good old fashioned torrential downpour.ReplyDelete
I've got ~11 mm in my self-made gauge in Fort Garry South.ReplyDelete
Less than 10 mm. here in Elmwood.ReplyDelete
McPhillips/Perimeter got a few rain drops that is about itReplyDelete
Bloody hell. I left my place near the Grant Avenue - Kenaston interchange at approximately 6:00. I don't have a store bought rain gauge, but I forgot an empty coffee cup on the patio.ReplyDelete
I spent a couple of hours in Waverley Heights. There was rain there but nothing outstanding. I got an urgent call to return home so I drove down Waverley where it was flooded in two or three spots with bumper high water.
Some guy tried to drive through one flooded spot and his car died in the attempt.
I saw my coffee cup on the patio and noticed it was almost full.... 73 mm of water.
Now I believe those forecasts.
here I got 25 mm in fort garry near crescent drive. Rain was coming down heavy at times.ReplyDelete
I was at the Ikea around 7PM but didn't notice anything out of the ordinary, then all of a sudden the sky just dumped massive amounts of water. Really intense. Like being in a shower at Gimli Beach.ReplyDelete
Apparently it was a once in a centure event. Seems we hear that often though, if my memory is correct, the storms of May 28-29, 2010 and July 16-17, 2005 were once in 100 year events too.ReplyDelete
Between the GEM, NAM and GFS, which one is the most accurate for summer temperature forecasts in this part of Canada?ReplyDelete
Another round of heavy rain possible early tomorrow morning somewhere over North Dakota and Southern Manitoba. A low level jet (around a slow moving disturbance in the Dakotas) will interact with 750-1000 J/kg CAPE and 40 mm of precipitable water, to produce the potential for heavy rain. The relatively slow movement of the system, and SE flow from 500 MB to the surface.. may lead to some back-building convection and possible training of cells.ReplyDelete
That "once in a century" term is often misused and misunderstood, especially by the media, politicians, and sometimes even engineers. You can say "once in a century" for river flooding because the flow gauge is at the river where it always floods (ie. you don't get river flooding a mile away from the river without also flooding at the river).ReplyDelete
But "once in a century" for a heavy rain event applies only to the weather station where the records were taken. You CAN reasonably extrapolate and proxy that across the city to say that 'any single location' in the city has a 1 in 100 year chance of that event occurring. But that's NOT the same as saying it's a "once in a century" event for the entire city of Winnipeg, because just like yesterday where the airport didn't get the major dump, it may have occurred many times before within Winnipeg but not at the airport.
Not to downgrade the event however, it was a wall of rain, and I'm very glad it wasn't any worse at my place.
I am working at NWS Grand Forks tonight and just not seeing much going on in our region overnight into Saturday. Low level jet is from central Nebraska into southern Minnesota and warm front is in that location. Looks like all the action will be down there. Also a few storms from eastern MT into Sask around upper trough. Even Sat night-Sun would show mostly SD into MN.ReplyDelete
Heavy rainfall warning out for parts of southwestern MB.ReplyDelete
"An area of thunderstorms tracking northeast over Southwestern Manitoba is giving heavy rain from Melita through Shoal Lake early this morning. By the time the rain moves out later this morning, total accumulations through parts of these regions will range from 50 to 75 mm in some areas. The rain is expected to weaken somewhat as it moves toward Dauphin and Swan River with lesser amounts expected in those regions.
This rain is associated with a low pressure trough over the Dakotas combined with an unstable airmass over Southern Manitoba. Little change is expected in this weather pattern and as a result heavy downpours may occur over other parts of Southern Manitoba this weekend. "
GEM-REG is showing from 100 to 150+mm from the US border to Swan River in next 2 days! Seems rather extreme. The prairies aren't having a very good week!
Good points re: Once in a century events. As you say, these are return periods for a single point, not an entire city, especially when you're talking about thunderstorm rainfall which has distribution ranges on the scale of city blocks.
That being said, I do wonder if the return period of these heavy rainfalls are getting shorter based on some of the rainfall events we've been seeing over the past decade or so (or is it a case of more and better sampling?)
Has anyone heard anything about flooding in southwestern Manitoba yet? Apparently 50-100 mm of rain fell there last night and early this morning and apparently a state of emergency due to flooding in Reston. News is so concentrated on Alberta at the moment, wondered if anybody heard anything from southwestern Manitoba.ReplyDelete
If there isn't flooding there yet, there may be tomorrow. The 12Z REG-GEM still has areas of 100mm+ over western MB.ReplyDelete
At suppertime, CBC radio said the fire truck was pumping in the streets at Reston and was just starting to make some headway. Lots of basement flooding. I wonder if EC put out a warning?ReplyDelete
Forecast for Brandon.ReplyDelete
Sunday, 23 June Cloudy. 30 percent chance of showers early in the morning. Rain with a few thunderstorms beginning early in the morning. Risk of a thunderstorm early in the morning. Amount 20 to 30 mm. Wind becoming northeast 30 km/h then light early in the afternoon. High 20.
Could they not have simplified that forecast....LOL
Sigh... I cringe when I see forecasts like that. That's what you get with automated forecast production systems that don't have a lot of smarts built in. It's bad enough that it reads like that.. but when it doesn't even verify, it makes it even worse (The rain started after midnight. So much for all that detail for early in the morning)ReplyDelete
Back in the day when human forecasters wrote the forecast, that type of forecast wording never would have gone out. Forecast would have just said "Periods of rain with a few thunderstorms." And it would have verified better.
The NAM came in line with the GEM showing heavy rain up the west side today (before the NAM was angling off into the Interlake). The province will likely be issuing a flood bulletin/warning today.ReplyDelete
Is that rain still going to hit Winnipeg today? Anyone know what time it is expected?ReplyDelete
Yes, still expecting rain here in Winnipeg. Showers expected to spread across the southern RRV shortly and then continue north into Winnipeg by mid afternoon continuing into this evening before tapering off by midnight or so. Might see an embedded thunderstorm in there as well.
Leading edge of showers up to an Elm Creek to Morris line spreading north towards the city. Showers moving into the city from the south by 1:30 pm. Could see some brief heavy downpours with some lightning strikes noted east of Carman.ReplyDelete
Not often we get this much rain without thunder or lightning.. Getting some minor street flooding.ReplyDelete
Forecast for Winnipeg tomorrow: "Increasing cloudiness. 70 percent chance of showers late in the morning and early afternoon then 30 percent chance of showers in the afternoon. Risk of a thunderstorm late in the morning and in the afternoon. Wind becoming east 20 km/h late in the afternoon. High 27. UV index 7 or high.ReplyDelete
The implied precision in this forecast is not only unrealistic, but misleading in that it suggests we can actually forecast to that level of detail. But a computer generated forecast doesn't know that. I see more and more of this unrealistic detail in forecasts both in Canada and the US as we move towards automated forecast production. Too bad they haven't figured out that the more detail you put in a forecast, the more likely that it won't verify.
A record high of 31.1C at Yellowknife NWT today.. which means they hit the 30C mark before Winnipeg!ReplyDelete
Rob, when do you think Winnipeg airport will hit it's first 30 C of the season? I think the end of next week we will crack the 30 mark.ReplyDelete
At least Winnipeg has a shot at 30C tomorrow.. if we get enough sunshine.ReplyDelete
>> Forecast for Winnipeg tomorrow: "Increasing cloudiness. 70 percent chance of showers late in the morning and early afternoon then 30 percent chance of showers in the afternoon. Risk of a thunderstorm late in the morning and in the afternoon. Wind becoming east 20 km/h late in the afternoon. High 27. UV index 7 or high.ReplyDelete
Forecast now reads "Sunny. Becoming a mix of sun and cloud this afternoon." No mention of showers or thunderstorm. So much for all that detail from yesterday. Just goes to show you that just because a computer can give hourly forecast data, it doesn't need to appear in that detail.