An unstable weather system over parts of Alberta, Saskatchewan, Manitoba and North Dakota is expected to produce up to 20 millimetres of precipitation in some areas by Friday morning. Localized cells could bring up to 100 mm over central Manitoba and up to 150 mm over central Saskatchewan.
Some areas of Manitoba have received significant rainfall since midnight from the unstable weather system. Rainfall received today as of 7 a.m. is shown in the chart below.
• Rossburn 28.19 mm
• St-Lazare 27.94 mm
• Grandview 48.26 mm
• Dauphin 33.02 mm
• Fork River 34.8 mm
• Russell 17 mm
• Birtle 14.6 mm
If the forecast storms do occur in the next 24 hours, localized overland flooding may occur, with possible significant water level rises on streams in areas already wet from previous storms including Dauphin, The Pas and parts of the northern Interlake region.
Environment Canada has also issued a strong wind warning for Lake Manitoba, Lake Winnipeg and Lake Winnipegosis as well as a squall warning for Lake Manitoba.
Provincial wind set-up alerts forecast for today and tomorrow include:
• A high wind set-up alert is issued for the east shore and southeast corner of the south basin of Lake Manitoba. This includes communities such as Twin Lakes Beach, St. Laurent and Lundar Beach.
• A moderate wind set-up alert is issued for the east shore of the north basin and the Narrows and a portion of the south shore of Lake Manitoba, as well as the east shores of Lake Winnipeg and the east and north shores of Oak Lake. This includes communities such as Steeprock, Vogar, Delta Beach, Victoria Beach, O’Hanly, Cherry Point and Oak Lake Beach.
• The moderate wind set-up alert for tomorrow does not include the north shores of Oak Lake.
Winds on Lake Manitoba are west at 37 km/h this afternoon and are forecast to increase to 56 km/h this evening, and change direction to northwest at 27 km/h tomorrow evening. Winds on Friday are forecast to be northwest at 27 km/h and forecast to change direction to east at 37 km/h in the afternoon.
Winds on the South Basin of Lake Winnipeg are light this afternoon, becoming southwest at 37 km/h later in the afternoon and forecast to increase to west at 56 km/h after midnight where they will remain until decreasing to northwest at 37 km/h tomorrow evening. Winds on Friday are forecast to be northeast at 27 km/h in the morning, changing to east at 37 km/h in the afternoon.
Winds on Lake Winnipegosis are southwest at 18 km/h this afternoon, forecast to increase to 37 km/h this evening and to continue to increase overnight to become west at 56 km/h tomorrow morning before decreasing a little to north at 37 km/h in the evening. Winds are forecast to diminish to light on Friday.
Wind set-up alert maps are available on the Manitoba Water Stewardship Flood Response webpage at www.manitoba.ca/flooding.
Due to the persistent hot, dry weather during the last several days, evaporation losses on Lake Manitoba may be greater than considered in the forecast. Lake Manitoba water levels may be near peak due to the greater evaporation losses if the hot, dry weather continues, but may still rise as the combined inflow from the Portage Diversion and the Waterhen River is still greater than the outflow through the Fairford River. Heavy rainfall over the lake could also result in some water level rise. Manitoba Water Stewardship continues to closely monitor the conditions on the lake. Any change to the Lake Manitoba forecast will also affect the forecasts for Lake Pineimuta and Lake St. Martin.
The Fairford River water control structure continues to operate at full capacity due to the high level of Lake Manitoba.
The Assiniboine River upstream of the Portage Diversion is forecast to decline by about 500 cubic feet per second (cfs) to 1,000 cfs per day for the next few days. It is currently expected the diversion will remain in operation until the first week of August. Flows in the diversion channel today are 11,840 cfs and the river downstream is at 16,960 cfs.
The Souris River, the Saskatchewan River at The Pas and the Carrot River continue to decline in Manitoba.
Water levels on the Red River continue to decrease and floodway operations ended on July 18. Manitoba Water Stewardship will monitor future weather forecasts for extreme precipitation events that may require operation of the floodway again until the Red River reaches normal summer levels within Winnipeg.
For more information, see www.manitoba.ca/flooding. The most up-to-date highway information is at www.gov.mb.ca/mit/roadinfo or 1-877-MBRoads (1-877-627-6237) and on Twitter by following @MBGov.
