|WPC 48 hr rainfall forecast (inches) through Monday |
70-80 mm noted through Interlake and western MB
with 30-50 mm over the RRV including Winnipeg
It's going to be an interesting 24 hours coming up over southern MB as a strong low pressure system over the western Dakotas tracks into southwest Manitoba Sunday. Showers will spread into southern MB this evening ahead of a warm front associated with the storm system, with heavier showers and thunderstorms likely overnight into Sunday morning as increasingly moist conditions spread north. Some of the rainfall could be quite heavy tonight into Sunday, with amounts of 25 to 50 mm possible across much of the Red River valley by Sunday morning. Rainfall rates may be torrential at times, which could cause local flash flooding especially in urban areas. Showers and scattered thunderstorms will settle across the Interlake and western MB Sunday giving widespread soaking rains in those areas, with local amounts of 50 to 75 mm possible by Sunday night. Further south, showers and thunderstorms will move out of the RRV Sunday morning, with a southerly flow bringing warmer and more humid conditions by the afternoon. An approaching cold front however will set the stage for scattered thunderstorms to develop over the RRV and SE MB Sunday afternoon into the evening.. with a risk of locally severe thunderstorms if there's enough sunshine that breaks through in the warm sector. (See local stormchaser Dave Carlsen's blog entry on Sunday's severe thunderstorm potential
) Much cooler conditions will follow in the wake of this cold front Monday and Tuesday with high temperatures only in the teens. All in all, an active period of weather coming up over the next 24 hours!
|EC Summary of rainfall amounts over weekend|
Generally about 20-30 mm of rain across Winnipeg and most of RRV overnight, with 30-40 mm over western RRV (Portage-Carman-Morden area) Rainfall amounts were about half what models were suggesting for Winnipeg and area, mainly due to lack of overnight convection (thunderstorms) that would have increased amounts. Bulk of rain pushing into the Interlake now (with exception of narrow heavier band just east of city at the moment) so I suspect rainfall warnings for Winnipeg and RRV will be ended shortly. Now we wait for afternoon convection, although activity will be contingent on how much sun can break through cloud cover (better chance towards US border)ReplyDelete
Glad to see you back posting to this blog. We all missed you Rob. Chris in Westwood.ReplyDelete
Finally starting to get some better clearing working in from the SE with T and Tds in the 27/20 range advecting in. So far only modest cumulus development along the surface trough slicing in from southwest to northeast. As often happens in these cases, so far main activity is elevated with some stronger cells passing west of Portage. Still time for the development of severe surface based storms but the window is closing. We'll see what happens to that cumulus line as it crosses into Manitoba..ReplyDelete
Any chance of Sunday's rain missing us?
Anon.. All models are basically on board with some showers moving into Winnipeg/RRV Saturday night into Sunday morning. General rainfall estimates at this point are between 5 and 15 mm for Winnipeg, but that is a very preliminary estimate this far out. It's possible things could move through quicker, in which case we'll have less rain and a drier Sunday.. or things can slow down which would prolong the rain Sunday. Right now, model consensus is for showers to move east of Winnipeg Sunday morning so we may be able to squeeze out a decent afternoon.Delete
Precipitable waters of near 40 mm along with strong band of midlevel frontogenesis responsible for the torrential rains today.. even with main axis of LLJ and moisture transport well SE of the area. Copious moisture 'bled over' from a southern stream disturbance affecting the midwest and was tapped by the trough in the northern branch of the jet stream. Models hinted at this moisture surge, and it manifested itself as broken stratus streaming northwards yesterday afternoon and overnight.ReplyDelete
For tomorrow, next pacific disturbance moves in and moisture will rapidly stream northwards again. This system will have good linkage with the plains LLJ (50 kts) with PWATs again in the 40 mm range. This spells the potential for an elevated complex of convection early Sunday with maximum LLJ convergence between 7 and 10 AM. One limiting factor may be instability which remains best just south of the border.
Thanks for the analysis.. surprising how heavy the storms were this morning to our south and east even though they were behind the cold frontal tough. Must have had some elevated support as you mention to maintain their strength, and tap the abundant moisture. Once again, another flash flood event (last week over Winnipeg), with 50-100 mm of rain within 90 minutes over the Domain-Niverville-Steinbach area. Just goes to show you how these flash flood events seem to be occurring more frequently in an increasingly more humid climate in the Prairies.Delete
Yeah, increased moisture availability and transport. At the same time, seemingly an increase in drought conditions also, with only spotty convection during periods of July.Delete
Swath of very heavy rain late this morning through midday from a thunderstorm south of the city that tracked from the Brunkild area through Domain and Niverville to Steinbach and east. Some rainfall amounts reported include..ReplyDelete
Niverville.... 125 mm (unofficial, from town mayor)
Domain .......94 mm (rain gauge measured)
Steinbach .. 66 mm (MB ag station)
La Broquerie... 54 mm
Rain fell mainly within 60 to 90 minutes, so these were tremendous rainfall rates.. similar to what happened in Winnipeg last Thursday. Lots of photos of flooded streets and parking lots in Steinbach.
Another 21.6 mm today at my place.. that makes 137 mm total for August. Airport got 18 mm today, 104 mm for August. Forks had 133 mm, while Tuxedo-Linden Woods area got over 170 mm for the month. Most of it was over the last 2 weeks. Normal August rainfall in Winnipeg is 77 mm.ReplyDelete
Having some issues with my main website not updating my weather station data graphic. Still stuck on 2:30 pm readings. Trying to troubleshoot problem.ReplyDelete