Wild weather ride to start the week with Warnings and Special Weather Statements issued

With a powerful Colorado low impacting the region over the next two days, parts of the province will see significant rainfall, strong wind gusts and potentially severe thunderstorms.

Environment Canada has issued a Special Weather Statement for all of Southern Manitoba, with somewhere between 30 and 50mm of rainfall expected by Tuesday night, as well as a Wind Warning for all of Southwestern Manitoba, as far east as the Pilot Mound and Manitou regions.

"Over the next thirty-six to forty-eight hours we are looking at a wild weather ride throughout much of the province," said CMOS Accredited Weathercaster Tuesday morning. "This system is moisture packed, full of instability and is setting the stage for potentially intense weather conditions."

According to Environment Canada, the first band of showers and thunderstorms will move in from the south Monday afternoon, with several more rounds expected before the system finally departs Tuesday evening. 

"It's important to note the rainfall totals mentioned are general estimates, and there is a strong likelihood of much higher localized amounts from embedded thunderstorms as these bands of showers move into the province," explained Sumner. "Some of those thunderstorms may reach severe limit criteria, and it's likely Watches and Warnings will be issued later Tuesday."

And with that in mind, severe weather season arrived with the region's first Tornado Watch of the year issued Sunday for the Morden, Winkler, Altona and Morris areas.

"Thankfully we didn't see any tornado activity, and that's always good news," said Sumner. "The Tornado Watch was issued because conditions south of the border were ripe for rotating thunderstorm development. The general track of those storms was northward from North Dakota, hence the watch being issued. Several Severe Thunderstorm Warnings were issued for parts of the southwest including the Municipality's of Boissevain-Morton, Killarney-Turtle Mountain, Lorne, Louise and Argyle. Those regions saw isolated severe storms, with heavy downpours in some locations and a few reports of hail."

The following rainfall totals are courtesy Environment Canada, the Manitoba Ag Weather Network and PembinaValleyOnline Rainwatchers and are for Sunday, May 29th:

Boissevain - 23mm (around 9/10ths)
Morris - 15.4mm
Pilot Mound - 15.2mm (just over 6/10ths)
Baldur - 11.4mm
Altona (rural) - 9.4mm
Steinbach - 9.3mm
Dominion City - 8.8mm
Emerson - 7.5mm (3/10ths)
Gretna - 7mm
Altona (in town) - 5mm (2/10ths)
Carman - 4.3mm
Morden - 4.2mm
Elm Creek - 3.5mm
Cartwright - 3.3mm
Winkler - 3.1mm
Manitou - 2.8mm (just over 1/10th)
25mm = 1 inch

Meanwhile, Sumner says, at this point, it appears the highest risk for severe thunderstorm development Tuesday afternoon and evening will be east of the Manitoba escarpment, through the Red River Valley and into Southeastern Manitoba.

"If I were to place a bullseye over a map, regions south of the Trans Canada and east of Highway 75 would be where I would be placing it," he added. "Right now, that region has the highest potential for today. With that said, this is a dynamic system. It's complex, and its storm track will adjust throughout the day. That means there could be some movement in that risk area."

Ahead of what could be yet another major rainmaker for an already soaked and soggy region, the Manitoba Hydrologic Forecast Centre has issued an overland flood warning for the southeast corner of the province for Monday and Tuesday (see highlighted area in the below map). The warning noted, water levels on lakes, streams, and drains are high and soils are saturated. Intense and heavy rains in these areas could result in overland flooding. Depending on the amount and intensity of rain, water levels could rise rapidly.

Adding to the concern are the very strong northerly winds starting later today. With gusts expected between 80km/h and 100 km/h in the Interlake, the Centre has issued a high to severe wind effect warning for Tuesday for the south basins of Lake Winnipeg, Lake Manitoba, Lake Winnipegosis and Dauphin Lake. The winds will cause water levels to rise by over five feet along shorelines and cause powerful wave action that will further add to the temporary increase in water levels.

"The take away from all of this is be weather aware over the next couple of days," stressed Sumner. "Keep a close eye on the forecast, and have multiple ways to receive Watches and Warnings, because it's essentially a guarantee they will be issued."

Overland flooding map from Manitoba Transportation and Infrastructure