A hot and sunny Canada Day on tap.. thunderstorms possible Monday

It's going to be a hot and sunny day for Canada Day celebrations in Winnipeg and southern Manitoba Sunday. Temperatures are expected to hit the 30C mark Sunday afternoon under blazing sunshine and light winds, so don't forget the hat and sunscreen if you're out! Fortunately, humidity levels will be tolerable with afternoon dewpoints in the mid teens expected. By late Sunday, thunderstorms are expected to fire up over southern Sakatchewan, possibly severe. These storms are expected to track across southeast Saskatchewan into southwest Manitoba Sunday night into early Monday, before weakening somewhat as they push into the Red River valley by midday Monday. Additional thunderstorms are possible later Monday over southern Manitoba depending on how much morning activity clears. Sunny and hot weather is expected to return Tuesday before another threat of thunderstorms moves in Wednesday.

Unsettled pattern coming to an end... brighter drier weather ahead..

The unsettled weather of the past two weeks will finally be giving way to a sunnier and drier pattern by Friday into the weekend, offering some much needed time to dry out from the recent damp and dreary weather.  Winnipeg has not seen more than 2 rainfree days in a row since June 4-6th, with frequent showers and occasional thunderstorms dumping over 50 mm of rain in the past 2 weeks at Winnipeg airport, and over 70 mm at my Charleswood site.  An upper ridge of high pressure is forecast to build over the Prairies over the weekend into next week which will finally take a stubborn storm track north of the southern Prairies, and also allow warmer air to push into our region. With increasing sunshine, temperatures should finally rebound back into the mid 20s over the weekend, with above normal temperatures possible next week.    

Thunderstorms over RRV/SE MB today.. unsettled weather pattern continues into next week

A roller coaster weather pattern is expected over the next few days over southern Manitoba as a series of disturbances race across the central continent every 2-3 days. The result will be alternating days of sunshine and unsettled weather with showers and thunderstorms every other day or two.  For today, a low pressure system tracking through the Interlake will swing a frontal trough across the Red River Valley, setting the stage for thunderstorm development this afternoon mainly east of the Red River valley, although Winnipeg may see some thunderstorms as well. Some of the storms could be strong with heavy rainfall and hail especially over Southeast MB and closer to the Ontario border. Things will dry out tonight with a nice day shaping up Friday with sunshine and warm temperatures in the mid 20s. Another band of showers and thunderstorms is possible Saturday, again with locally heavy rain rain possible, with a drier day forecast Sunday for Father's Day, and the annual Manitoba Marathon. More unsettled weather is expected Monday into Tuesday.

Large hail pounds west Winnipeg Saturday evening..

Large hail hits parts of Winnipeg
Saturday evening June 9 2012

A severe thunderstorm with large hail tracked over Winnipeg between 9:45 and 10:15 pm Saturday evening, dropping hail the size of golf balls and even tennis balls over parts of the city.  The largest hail appears to have fallen over the west end of the city in St James and Charleswood, with golf ball size hail (4 cm) at  my place between 9:50-9:55 pm. The storm was part of a line of severe thunderstorms that developed rapidly Saturday evening over the southern Red River valley and tracked northeast. This particular storm formed  rapidly south of Sanford around 9:15 pm, and within 30 minutes was tracking into the southwest part of the city dumping heavy rain and destructive hail (2nd radar image).  The storm brought 2.5 cm hail to the YWG airport at 9:54 pm before moving over the north part of the city and off towards Lake Winnipeg. The severe storms were part of a highly volatile environment Saturday with plenty of instability and wind shear to produce severe thunderstorms. The day spawned numerous reports of severe weather with mainly large hail and heavy rain.  Unsettled but cooler conditions are forecast for Sunday.   

Hailstorm approaches southwest Winnipeg around 9:45 pm 
Perimeter at McGillivray  (photo Audry V)

Severe storm at 9:40 pm intensifying south
of Winnipeg 

Severe storm with hail hitting west end
of city 9:50 pm June 9 2012

Improving conditions today.. severe weather threat looms Saturday over southern Manitoba..

Unsettled weather this morning with occasional showers over the Red River valley will give way to a drier westerly flow as the day progresses, with breaks of sunshine this afternoon allowing temperatures to rise into the mid 20s. The dry and benign weather will continue tonight into most of Saturday, before a potential outbreak of severe weather develops over southern Manitoba later Saturday into Saturday night. Warm and humid conditions combined with increasingly favourable upper winds and an approaching frontal system will set the stage for thunderstorms to develop over southern Manitoba late Saturday, with a likelihood of some severe thunderstorms developing giving large hail, strong wind gusts and possible tornadoes.  At this point, it's still too early to say when and where thunderstorms will fire up Saturday, but current model guidance is hinting that the highest threat of severe thunderstorms will be over southwest Manitoba along the international border into southern Red River valley. Note though that much of southern Manitoba including Winnipeg will be under a threat of severe storms by later Saturday into Saturday night.  Stay tuned on this developing severe weather situation..