Updated at 6:35 a.m. Monday, April 17th - According to Environment Canada, a significant spring storm is set to bring a mix of rain and heavy snow to portions of southern Saskatchewan and southwestern Manitoba Tuesday night into Thursday this week. Special Weather Statements have been expanded Monday morning to include all of Western Manitoba, as well as the western Red River Valley ahead of the system's arrival.
"Total snowfall amounts will likely be in the 10 to 20 cm range by the time the system departs late week, however, as is the case with many late season significant storms, forecasting this system has proved to be quite a challenge," said the weather agency in the Statement. "There remains to be uncertainties with the evolution of this system, ranging from timing the onset of rain turning to snow, snowfall totals, and the corridor of heaviest snowfall. In general, various model guidance remains muddled, with little in the way of a consensus of areas affected and total precipitation amounts."
At this point, rain mixed with snow will move into Westman Tuesday evening, with precipitation full transitioning to snow overnight on Tuesday. The heaviest snowfall will begin to fall early Wednesday morning. Total accumulations of all types of precipitation may exceed 20 mm for some areas, potentially greatly exacerbating the flood situation for some regions.
The highest confidence for the heaviest precipitation lies over eastern Saskatchewan and western Manitoba, roughly from Regina to the Manitoba Parklands. The greatest uncertainty lies over western Saskatchewan, west of Regina, and the eastern Red River Valley.
Gusty winds will also be a concern, in addition to the snow, with moderate to strong easterly winds leading to poor travel conditions, particularly on Wednesday.
Snowfall or winter storm watches and warnings will likely be forthcoming for some regions as the event draws nearer and the evolution of the low pressure system in the United States becomes more clear.