Warm and humid conditions across Southern Manitoba, coupled with the slow eastward trek of a surface low pressure system, led to multiple Severe Thunderstorm Warnings and reports of large hail, heavy rain and strong winds Monday evening. In addition to that, several Tornado Warnings were issued, including for the R.M.'s of Dufferin and Grey.
"Those warnings were issued based on one particular thunderstorm cell exhibiting tornadic characteristics on RADAR," explained CMOS Accredited Weathercaster Chris Sumner. "Environment Canada will issue Tornado Warnings under a couple of scenarios; when a tornado has been confirmed on the ground and reported, or when there are indications based on RADAR, or from a reliable spotter one is imminent. In Monday evening's case, the Warning was prompted by RADAR indications."
According to Sumner, the Tornado Warnings were not in effect long, but the area of severe thunderstorms which prompted it did pack a punch.
"In some areas, these storms stayed over one region for a relatively extended period of time, and that led to significant rainfall totals," he added. "It appears areas from Highway 23 northward into the Interlake and the Whiteshell were the hardest hit."
The following are rainfall totals from PembinaValleyOnline Rainwatchers, Environment Canada and the Manitoba Ag Weather Network and are for August 15th, 2022:
Vivian - 83.3mm (3.3 inches - located south of Beausejour)
Elie - 68.4mm (2.7 inches)
Morris area (rural) - 50mm (2.5 inches)
Winnipeg (airport) - 58.8mm (almost 2.4 inches)
Portage - 56.7mm (almost 2.3 inches)
Marchand - 55.2mm (2.2 inches)
St. Adolphe - 51.5mm
Starbuck - 44.3mm
Steinbach 38.1mm (about 1.5 inches)
Morris - 27.0mm (1.1 inches)
St, Pierre - 26.6mm (a little over 1 inch)
Brunkild - 22.2mm (9/10th)
Elm Creek - 20.0mm (8/10th)
Woodmore - 12.5mm (1/2 inch)
Kane - 9.6mm (just under 4/10th)
Carman - 8.0mm
Manitou - 2.8mm (just over 1/10th)
Clearwater - 2.7mm
Dominion City - 1.3mm
Altona - 0.8mm
Winkler - 0.4mm
The unsettled conditions will continue Tuesday.
"Daytime highs will be a couple degrees cooler than yesterday, but we are expecting that warm and humid airmass to be a big part of the weather making recipe," noted Sumner. "An upper ridge of high pressure is allowing that airmass to continue to be present here, and it will feel like the low 30s in most areas, even though actual temperatures are between 23 to 25. Meanwhile, another minor disturbance moving through the region could kick off a shower or two later today and this evening, but at this point, we're not expecting severe thunderstorm activity to develop."
Looking ahead to the rest of the week, another partly sunny and muggy day is lining up for Wednesday, with temperatures between 26 and 28, but feeling like the mid 30s once the humidity is factored in.
"A cold front moving through Wednesday evening to Thursday will drop temperatures substantially, landing us around 20-ish Thursday, with showers expected across Southern Manitoba," he said. "The cool down won't last long, with high pressure returning Friday, with sunny and seasonal conditions expected through the weekend."