Environment Canada ended a severe thunderstorm warning for London-Middlesex and Southern Huron County Sunday evening.
Just after 6 p.m., meteorologists said they were tracking a slow-moving line of thunderstorms capable of producing more than 50 mm of rain.
Shortly before 7:30 p.m., the warning was lifted for London-Middlesex and the warning for Goderich, Bluewater, and Southern Huron County was ended shortly after that.
The weather agency said the storm could cause flash flooding and that a funnel cloud has also been reported. "[The funnel cloud's] weak rotation is normally not a danger near the ground. However, there is a chance that this rotation could intensify and become a weak landspout tornado," a statement read.
Motorists are warned to be cautious of fast-moving or pooled water on roads. The Office of the Fire Marshal and Emergency Management recommended taking cover immediately if threatening weather approaches.