Update Thursday, May 30th at 5:20 p.m. - Environment Canada has expanded the previously in place Wind Warning to the western Red River Valley, now including all of Southwestern Manitoba as well as the Morden, Carman, Winkler, Altona and Morris regions.
Northerly winds will begin to strengthen Monday evening, and reach 60 km/h gusting to 90 km/h late tonight. The strong winds will continue through the overnight hours into Tuesday morning. The gusty conditions will diminish Tuesday afternoon as the low moves into northwestern Ontario.
“The winds will first pick up on the southwestern part of the province, and build eastward throughout the late evening hours, overnight and into Tuesday morning for the eastern half of the province,” said CMOS Accredited Weathercaster Chris Sumner late Monday afternoon.
Meanwhile, a Special Weather Statement remains in place for most of Southern Manitoba as already water logged areas brace for significant rainfall over the next twenty-four hours.
“We are still expecting somewhere within the range of 30 and 50mm by the time the tap turns off Tuesday,” added Sumner. “The additional rainfall is once again putting us into the position of having to be concerned about overland flooding in areas already hit hard at the end of April and early May.”
With that in mind, the Manitoba Hydrologic Forecast Centre has expanded the overland flood warning issued Sunday to include areas east of Highway 5 from the U.S. border to the Trans Canada at Carberry, and south of Lake Manitoba including Portage la Prairie, Selkirk and Winnipeg. That’s in addition to the initial area which included much of the Red River Valley, Southeastern Manitoba and the Whiteshell.
Flood warnings have also been issued for the Pembina River system including Pelican and Rock Lakes and Boyne and Red river tributaries.
The updated forecast indicates the low could now affect expanded areas along the western portion of the Red River Valley, with heavy rain Monday evening lasting until Tuesday morning. Areas around Treherne, Morden, Winkler, Altona, Morris, Emerson and Gretna are expected to receive higher amounts adding to overland flooding concerns.
As for severe thunderstorm activity, Sumner added that target area has shifted further east than initially forecast Monday morning.
“At this point, I’m looking at the extreme southeastern corner of the province including the Piney, Sprague and North West Angle Provincial Forest regions,” he explained. “Essentially, if you were to draw a line from Hadashville south to Piney, and then eastward to the Ontario border, that is the area with the highest potential for development this evening. With that said, all regions near the U.S. border from south of Altona eastward have a marginal chance of severe thunderstorms potentially moving northward out of North Dakota and Minnesota Monday night.”