Environment Canada was advising of the potential for heavy rainfall Wednesday.
The national weather agency issued a special weather statement for Sarnia-Lambton, Windsor-Essex, Chatham-Kent, Middlesex County, Elgin County, Perth County, and Huron County just before noon.
The advisory was lifted for Middlesex County, Elgin County, Perth County, and southern Huron County around 4:30 p.m.
It was upgraded to a rainfall warning for Sarnia-Lambton at around 2:25 p.m., but the warning ended at around 4:40 p.m.
Local rainfall amounts possibly exceeding 50 millimetres were possible in thunderstorms during the afternoon and evening hours.
We were being reminded that heavy downpours can cause flash floods and water pooling on roads.
Localized flooding in low-lying areas was possible.
Heavy rainfall in combination with other weather factors, such as hail, wind and lightning was expected to make outdoor activities unsafe.