Beginning Thursday night, rainfall accumulations could reach as much as 90 mm (3.5 inches) in some places. Many parts of southeastern Saskatchewan could receive 40 to 80 millimetres by Saturday.
South-central areas are expected to receive the heaviest accumulations. Eastern portions of the Old Wives Lake Basin near Assiniboia, the Poplar River Basin near Coronach, and Avonlea Creek are particularly concerning.
The Water Security Agency (WSA) has stated that snowmelt runoff is complete for this area of the province and they do not expect significant impact to water flows and levels. However, localized issues are possible.
Areas east of Regina from the United States Border to Jan Lake, where conditions have been wetter over the past month, could see increasing flows - potentially to flood levels, particularly on Pipestone Creek, Antler River, and tributaries within the Lower Red Deer River Basin near Hudson Bay, including the Fir and Overflowing Rivers.
The Assiniboine River is still seeing some higher flows after the spring runoff and significant rainfall could cause the river to spill over, resulting in localized flooding.
The additional rainfall predicted will bring the Boundary and Rafferty reservoirs closer to their preferred operating levels, but is not expected to fill them.
A release was initiated from Grant Devine Dam on May 12 as it neared full supply.
The province warns that the public should exercise due caution around fast-moving water. Do not attempt to cross any areas where the depth of the water can't be determined.
The WSA also advises that if local municipal water systems become disrupted, drinking water advisories may be issued.