A severe thunderstorm watch remains in effect for Sarnia-Lambton, including Petrolia, Watford and the Pinery provincial park.

Environment Canada says conditions are favourable for the development of severe thunderstorms that may be capable of producing strong wind gusts and heavy rain.

Slow moving storms will be an issue to deal with into this evening. There is potential for some of them to become severe with torrential downpours resulting in as much as 50 millimetres of rain in an hour or less.

Frequent lightning and wind gusts to 90 kilometres an hour are also possible.