Two rounds of showers and thunderstorms Tuesday led to significant rainfall amounts for areas of the Red River Valley and Southeastern Manitoba.
"In the early morning hours of Tuesday, a warm front pushing southeastward from a line in the Interlake to the far southeastern corner of the province prompted Severe Thunderstorm Watches and Warnings," explained CMOS Accredited Weathercaster Chris Sumner. "That line of storms also packed substantial rainfall, with a moisture rich atmosphere primed to drop heavy rain. According to our Rainwatchers, there was also hail in the St. Pierre area, as well as in parts of the southeastern corner of Winnipeg."
The second round of precipitation came Tuesday evening when a trough of low pressure moved through the Red River Valley, adding more rainfall to yesterday's totals, primarily along Highway 75, and just west of it.
"Within about an hour, between 8pm and 9pm, that trough fired up relatively strong thunderstorms, which once again were in a moisture rich environment," said Sumner. "That set-up led to brief downpours, and pretty significant totals, in a relatively short period of time. Those storms also prompted Severe Thunderstorm Watches to be issued."
The following totals are courtesy PembinaValleyOnline Rainwatchers, Environment Canada and the Manitoba Ag Weather Network:
Zhoda - 73.2mm (almost 3 inches)
Steinbach - 63.5mm (just over 2.5 inches)
Marchand - 61mm
Menisino - 41.8mm (almost 1.7 inches)
Rosa - 40.7mm
Emerson - 39.1mm
Brunkild - 26.9mm
St. Adolphe - 26.3mm
Winnipeg (The Forks) - 23.9mm
Morris/Dominion City - 23.7mm (about 9/10th)
Winnipeg (airport) - 18.9mm
St. Pierre - 17.1mm
Altona (airport) - 15.6mm (about 6/10th)
Woodmore - 12.5mm (1/2 inch)
Altona (in town) - 8mm
Gretna - 1.9mm
25mm = 1 inch
According to Sumner, looking ahead to the rest of the week, one more hot and humid day for Southern Manitoba on Wednesday, with a southerly flow once again pumping humidity into the region, with upper ridging in the atmosphere helping keep things muggy and warm.
"We could see another round of thunderstorms Wednesday evening, with severe activity a possibility," he noted. "Daytime heating will lead to ample instability in the atmosphere, and a weak low pressure system over the region may provide the trigger to get things started."
For Thursday, temperatures are expected to return to seasonal for this time of year, with less humidity. For the weekend, which includes the Manitoba Sunflower Festival in Altona, Sumner said there is a fair amount of disagreement in the forecast models, specifically on how cool it may get due to a return to a northwesterly/northeasterly flow.
"Right now, it's looking like we may be a few degrees below average Friday and Saturday, landing between 22 and 24, with a slightly warmer day Sunday," he said. "A couple of weak disturbances may lead to shower chances Friday and then Saturday evening, but that is also somewhat uncertain, considering there will be less moisture in the atmosphere to work with due to the less humid conditions. Sunday is looking mainly sunny and seasonal around 24 to 26."
Averages for this time of year are 27 degrees daytime and 14 overnight.