Several regions across the Greater Toronto and Hamilton area are under a special weather statement.

Environment Canada is warning residents and drivers about significant rainfall in the forecast tonight, Sunday and Sunday evening.

On its website, it says a low pressure system is developing over the Western United States and will move towards Southern Ontario during the weekend.

The weather authority says “appreciable amounts of rain are likely in many areas especially Sunday and Sunday evening.”

Rainfall amounts of 25 to 40 mm are expected.

Environment Canada warns some areas may experience thunderstorms which could result in higher amounts of rainfall.