Torrential rains swamp Winnipeg

6 pm radar shows nearly stationary
thunderstorm complex over SW
Winnipeg into downtown core

After an extended period of warm and humid weather, Mother Nature unleashed over Winnipeg late Thursday afternoon with a nearly stationary thunderstorm complex that swamped much of the central and southern parts of the city. Thunderstorm cells started developing near the city around 5 pm.. and by 530 pm, a nearly stationary band of heavy thunderstorms had set up from the southwest part of the city into the downtown core.  Over the next 90 minutes, some 50 to 80 mm of rain /a month's worth of rain/ would fall across this swath, resulting in extensive flooded roads and underpasses, as well as flooded buildings (including Polo Park mall).  The rush hour deluge led to traffic chaos with several main streets in and out of downtown restricted or blocked due to floodwaters. City officials are describing the event as a 1 in a 100 year storm based on rainfall intensity. ( More photos and stories on the flooding from Winnipeg Free Press and Winnipeg Sun. )

In one of the more popular images from Thursday's deluge,
a resident snorkels in floodwaters in Whyte Ridge
(SW Winnipeg) where 80 mm of rain fell in 90 minutes.

Flooded underpass at Higgins Ave.. one of several
underpasses that were flooded in Thursday's deluge

For some, a canoe offered a better mode of
transportation on flooded city streets

Select rainfall amounts from Thursday's deluge..  (unofficial)

Rainfall amounts over south Winnipeg from
WeatherFarm mesonet

Whyte Ridge ............ 81 mm
U of Winnipeg .......... 65-75 mm
Tuxedo .................... 70 mm
Waverly South ......... 70 mm
Grant Park ............... 65 mm
Linden Woods ......... 56 mm
Forks (EC) .............. 53 mm
Charleswood ............ 41 mm
St Vital ....................  25 mm
Winnipeg airport ....... 19 mm
Transcona ..............    5 mm

   
This was the second time this week that the Tuxedo to Linden Woods area has been hit with heavy rainfall. On Monday afternoon, a narrow band of heavy showers and thunderstorms dumped 35 to 50 mm along this swath. Tuxedo Park school recorded 49 mm Monday with another 70 mm Thursday, for a total of 119 mm within 4 days. Linden Woods has recorded 109 mm since Monday. Normal August rainfall is 77 mm in Winnipeg.

City of Winnipeg rainfall - Aug 21 2014 (between 4 and 10 pm)

The following is a map from the city of Winnipeg showing the distribution of rainfall in the city from Thursday's rainstorm. One can see the heaviest rain axis stretching from the southwest Perimeter into the downtown core up towards North Kildonan. The maximum was in the Whyte Ridge area which saw over 80 mm of rain between 530 and 730 pm. (NOTE: The Fort Whyte station recorded an erroneously low number on this map due to a plugged gauge) The city has a network of over two dozen rain gauges scattered throughout Winnipeg to monitor rainfall within the city, which can vary widely in short distances during convective storms (which is the primary mechanism for precipitation in the summer months here)  This network of stations helps give the city a much more detailed picture of rainfall distribution within Winnipeg, compared to only 2 official Env Canada sites in the city (Winnipeg airport and The Forks)  Link to City of Winnipeg rainfall map.

Nice warming trend this week.. risk of thunderstorms over weekend

CPC 6-10 day outlook valid
Jul 20-24 indicates return of
warmer air over southern MB 

After a record cool Sunday (max of only 15.7C), temperatures will be on an upswing this week as a deep vortex over Ontario shifts east and weakens. This will allow warm air over western and northern Canada to spread east into southern Manitoba over the next few days, along with plenty of sunshine. Temperatures will climb to 23C Tuesday and reach seasonable highs of 26C by Wednesday.  The heat will return for the end of the week with temperatures expected to hit the 30C mark Thursday and Friday. Things get a little more uncertain for the weekend, with models hinting at some showers or thunderstorms by Sunday with increased humidity. After that, indications are that temperatures will climb above normal again for early next week. All in all, looks like a nice taste of summer coming up after a brief flirt with fall Sunday!

Seasonably warm weather ahead.. but another cool outbreak Sunday into early next week as heat wave builds over BC

Looking for heat over the next week?
Head west!
CPC 6-10 day outlook looks cool
for southern MB/Ontario.

Pleasant summerlike weather is in store for southern Manitoba over the next few days as a ridge of high pressure over Manitoba gradually pushes east into NW Ontario. Temperatures will climb to about 24C today and into the upper 20s Thursday, before a weak cool front pushes through Thursday night bringing a threat of showers and thunderstorms across the RRV into early Friday. Pleasant weather is expected Friday and Saturday with generally sunny skies and temperatures in the mid 20s. Unfortunately, a cold front pushing in from the north will bring a threat of showers Sunday along with a northerly push of cooler air that will likely result in high temperatures of only 18-20C for Monday and Tuesday... well below the normal high of 26C for this time of year. This northerly flow will be the result of a massive upper ridge building over western Canada early next week that will bring an extended heat wave over BC, with temperatures in the 35-40C range in the Okanagan and Fraser Valleys. A gradual moderating trend is expected over southern Manitoba by the middle to end of next week.. but as of yet, there are no indications of a pattern change to hot dry weather over us in the near future.      

June 2014: A "normal" month temperature wise.. but much wetter than usual..

June 2014 - Winnipeg Airport
Daily temperature graph and
anomaly from normal

June 2014 in Winnipeg finished with an average temperature of 17.0C, right on average for June based on the 30 year normal.  The statistic is a bit surprising given the frequent cool and rainy spells that occurred, especially in the latter half of the month. However, there were enough warm days and mild nights to boost the monthly average to "normal" values.

Rainfall was a different story. A total of 147.1 mm fell at YWG airport during June, some 57 mm (63%) above the 30 year June average of 90 mm. According to JJ's Winnipeg weather blog, this makes this June the wettest June in Winnipeg since 2000 (177 mm) and the city's 12th wettest June since records began in 1872. Totals were even higher in other parts of the city with 167 mm at my location in SW Winnipeg, and 170 mm at  the Forks downtown. It also didn't help matters that much of the rain fell over the last 3 weekends of the month, spoiling summer weekend plans for many. The rain however was even worse over western Manitoba which was deluged with record rainfall during June. In Brandon, their June rainfall total of 251.6 mm was the wettest month on record since records began in 1890. Previous wettest month was August 1980 at 217 mm. The bulk of the rain fell over the last two weeks of the month, leading to widespread overland flooding over southwest Manitoba. Rivers and lakes are at very high to record high levels across southern Manitoba, with flood warnings and high water advisories on many lakes and tributaries.  The abnormally wet conditions prompted the opening of the Red River floodway on July 1st to ease the risk of flooding in the city of Winnipeg.

So is there any hope of drier weather the rest of the summer?  Too hard to say. The next few days look promising with drier weather for the balance of the week. Increasing heat and humidity over the weekend will lead to a greater chance of showers and thunderstorms developing over southern Manitoba, but hopefully the activity will be more scattered and transitory compared to the past few episodes. Beyond that, there are no clear signals as to how the rest of the summer will shape up. Certainly there's a lot of moisture around which helps to fuel more shower and thunderstorm activity. But a favourable upper pattern can shut off the taps for long stretches as well. We're approaching the peak of summer now (mid July is our summer peak in terms of average temperature), and hopefully Mother Nature starts to take a much-needed summer break soon!

Another unsettled weekend ahead.. showers and thunderstorms likely, locally heavy at times

Another weekend, another shot of unsettled weather coming up for southern Manitoba as a warmer and more humid airmass spreads over the eastern Prairies, while periodic weather systems trigger showers and thunderstorms Friday through Sunday. Much like last weekend, this upcoming weekend won't be a total washout with sunny, dry stretches at times. However, occasional showers and thunderstorms are likely each day, especially at night with the potential for some severe thunderstorms.. along with locally heavy rainfall. This will not be welcome news for those hoping to dry out from the wet weather over the past couple of weeks which has produced over a month's worth of rain in Winnipeg within a week. Cooler weather is expected to move in next week behind this unsettled weather pattern.