Environment Canada says the special weather statement has been issued for the following parts of the province:
- Windsor — Essex — Chatham-Kent
- Sarnia — Lambton
- London — Middlesex
- Oxford — Brant
- Huron — Perth
- Waterloo — Wellington
Environment Canada says that a low-pressure system is moving through the region, along with scattered thunderstorms that have "heavy downpours" associated with them.
A cold front is also moving through, which Environment Canada says will cause some heavy downpours and also increase the risk of thunderstorms.
It is not yet clear precisely where the storms will hit, but Environment Canada says some areas could get 30 to 40 milimetres of rain – and in some local areas, 50 or more millimetres.