The NPCA say the recent blizzard has resulted an average accumulation of 5-10cm of snow across the central, north, and west portions of the watershed and an average accumulation 15-30cm of snow along the southern watershed from Haldimand County to Fort Erie.
The current forecast is calling for temperatures to remain above the freezing mark for at least the next six days which will result in significant snow melt.
Rain is predicted to begin on Friday and continue into Saturday with rainfall accumulations of 15 to 25mm expected.
This rainfall combined with snow melting over saturated or frozen ground can cause significant runoff to be directed into local ditches, watercourses, and storm sewer systems.
The extent of flooding will depend upon the amount of rainfall that is received.
During this time, localized flooding is anticipated due to many roadside ditches being filled with debris, ice and snow.