Environment Canada has issued a Rainfall Warning for the Dryden and Ignace area.
The agency says rainfall amounts could be 30 to 50 millimetres by this evening.
It is possible that the heavy rain will continue over the area into tomorrow morning, potentially giving additional rainfall amounts of 30 to 50 millimetres.
Meteorologists note the track of the system is still uncertain and the rainfall amounts expected for tonight and Friday could change dramatically.
The low pressure system is located over North Dakota right now and is pushing moisture up from the Gulf of Mexico.