Environment Canada has issued a special weather statement for Hamilton and Brantford warning residents of the potential for heavy rainfall amounts in the area.
The warning extends through to Woodstock, the Niagara Region and Norfolk County.
The agency says the areas could see as much as 20-40mm of rainfall by the time the wet weather comes to an end.
Global News Chief Meteorologist Anthony Farnell noted on Twitter that localized flooding could occur in the region from Brantford to Hamilton.
He says some areas could see as much as 100 mm of rain.