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..

Next threat of thunderstorms moves into RRV Thursday evening

A trough of low pressure moving across southern Manitoba Thursday is forecast to produce an area of showers and thunderstorms over southwest MB by afternoon, likely spreading into the Red River valley by evening before weakening east of the valley Thursday night. The storms are not likely to be that severe owing to the lack of strong wind shear, however adequate moisture and instability will likely trigger a few strong storms with a slight risk of nickel size hail. More likely, the storms will produce locally heavy rainfall with local amounts of 25 to 50 mm possible, especially over western MB into the Interlake region. This band of showers and thunderstorms will gradually push through the Red River valley Thursday night into Friday, with a gradual drying trend by Friday afternoon. More unsettled weather with showers and thunderstorms is expected Saturday night into Sunday over the RRV, with a potential for some locally strong to severe thunderstorms. 

Scattered thunderstorms this afternoon over Red River valley/Interlake areas... some possibly severe..

A cold frontal trough over western MB will push eastward today tapping a warm and fairly moist airmass ahead of it over the Red River valley and Interlake regions this afternoon. Cloudy skies this morning will give way to some sunshine as the afternoon progresses allowing temperatures to rise into the low to mid 20s. This will set the stage for a line of thunderstorms to develop along and ahead of the trough line this afternoon mainly from the Interlake areas in through the Red River valley including Winnipeg. Some storms may become severe especially through the Interlake where upper winds are stronger, with quarter size hail, strong wind gusts and heavy downpours possible. Storm motion will be to the east-northeast at 30-40 km/h. Clearing conditions are expected by evening as the front moves east of the Red River valley.