Warming trend this week

After an early taste of fall like weather, temperatures will be returning to more normal values this week over southern Manitoba as a large cool airmass pushes east out of the Prairies. In its place, a moderating trend will become established over much of the Prairies as a zonal upper flow develops, allowing milder air from western Canada to spread east across the Prairies into southern Manitoba. This will allow temperatures to climb into the upper teens over the next few days and lower 20s later this week, which is near or even a bit above normal for this time of year (normal high for Winnipeg is now 18C)  High temperatures Wednesday may dip into the mid teens as we get sideswiped by a cold front pushing through the Interlake into NW Ontario, but then temperatures should rebound quickly for late week into the weekend and next week.  In addition, the weather should remain generally dry this week over southern Manitoba until Friday when a system will bring the next main threat of showers. The upcoming warmer and drier weather pattern will be most welcome by farmers looking to ramp up harvesting activities after an unsettled first week and cool second week of September.  

Enjoy the summerlike weekend.. an early blast of fall coming by Tuesday

Say goodbye to summer this week!
850 mb temperature map shows blast of cold air
flooding across the Prairies by late Monday

It was a lovely Saturday over southern Manitoba as afternoon sunshine and southwest winds pushed temperatures well into the 20s across the RRV, including a high of 25.3C in Winnipeg, about 5C above normal for this time of year. Sunday looks just as nice with sunshine and light southerly breezes pushing afternoon temperatures back to the 25C mark again.. perfect weather to enjoy the Broadway ManyFest street festival, the annual Bombers-Riders Banjo Bowl game, or any other late summer outdoor activities. Enjoy it while you can because there are BIG changes coming in the weather this week across the Prairies. An unseasonably cold airmass will be barreling down from the Arctic early this week, bringing a blast of well below normal temperatures from Alberta to Manitoba. This colder airmass will be ushered in by a cold front pushing across southern Manitoba late Monday into Monday evening. Temperatures in the 20s Monday afternoon will plummet Monday night, with temperatures on Tuesday struggling in the 10-13C range along with cloudy skies and brisk north winds, making it feel more like October than September. The cold weather will persist the rest of the week with cloudy skies, patchy light rain or drizzle, and temperatures only in the single digits to around 10C.  That's a good 10C below normal for this time of year.  If that wasn't bad enough, higher elevations of western MB (such as the Riding and Duck Mtns, Turtle Mtn, etc) may even see the season's first flakes of .. *gasp*.. SNOW by mid week! (Very early, but not unprecedented for those higher elevations) The saving grace is that clouds and wind may prevent a widespread killing frost during the week for the remainder of southern Manitoba, but if there are any areas that clear at night, frost will be a major concern during mid to late week. So enjoy the summerlike Sunday.. a taste (or more like a heaping serving) of fall is on the way!

Another round of rain..

WPC 24hr rainfall forecast (in inches)
valid Wed to Thur evening

Another storm system is forecast to track across the Dakotas tonight and across SE Manitoba Thursday bringing another round of wet and possibly stormy weather to southern MB. Scattered showers and thunderstorms in advance of the system will push across southern Manitoba this evening and tonight before a steadier area of rain pushes across western MB through the Interlake overnight through Thursday. Locally heavy rainfall is possible within this band, with amounts of 25 to 50 mm possible in some areas by Thursday evening. Heaviest rainfall is expected in southeast SK where up to 70 mm of rain is forecast by Thursday evening. Here in Winnipeg and the RRV, lesser amounts of rain are expected.. on the order of 10-20 mm, however locally heavy downpours are possible with any thunderstorms that track though tonight especially near the US border.   Rain will taper off Thursday evening across the Winnipeg area with clearing skies by Friday. Note also that strong northerly winds gusting to 70 km/h or more are expected behind this system by Thursday evening which may cause shoreline problems on southern ends of Lake Manitoba and Winnipeg Thursday night due to high water levels.  Sunny and seasonable weather is expected Friday into the weekend with a warming trend for Sunday and Monday as temperatures rise towards the mid 20s again. Unfortunately, the warmup looks short lived as another system tracks through Tuesday with more showers, and a change to much cooler weather for mid to late week next week. In fact, it's possible southern MB may be seeing its first frosts of the season by the end of next week.  

Soggy end to wet but warm August..

It was a wet finish to the month of August over Winnipeg and the Red River valley as another weather system brought widespread rain to southern Manitoba today. In general about 15-25 mm of rain fell in most areas, with 20 to 40 mm over parts of the southern RRV and southwest MB.  In Winnipeg, the official rainfall at the airport today was 18 mm, with 17 mm falling at the Forks. At my location in Charleswood, I picked up 21.6 mm today bringing my monthly total to 137 mm.. well above the August average of 77 mm. The bulk of this month's rain has fallen over the past 2 weeks, with a couple of significant rainfalls across the city including August 21st when a slow moving thunderstorm complex dumped 50-100 mm over the southwest to central parts of the city. Officially, the airport recorded 104 mm this month, while the Forks had 133 mm with amounts over 170 mm from the Tuxedo to Linden Woods area. 

The wet finish to the month was in sharp contrast to a dry July and first half of August which saw below normal precipitation in Winnipeg.  Temperature-wise, August will finish with an average temperature around 19.3C at YWG airport.. slightly above the average August temperature of 18.8C.        

Areas of heavy rain tonight into Sunday morning.. severe thunderstorm risk Sunday afternoon/evening

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