A cold front bringing relief from the heat and humidity was triggering heavy thunderstorms Monday.
Environment Canada elevated its severe thunderstorm watch to a warning for Sarnia-Lambton at 5pm.
Meteorologists were tracking a severe thunderstorm capable of producing very strong wind gusts, up to nickel size hail and heavy rain.
It was located six kilometres southwest of Brights Grove, moving east at 30 km/h heading toward Brights Grove, Wyoming and Reeces Corners.
The warning was ended at about 5:15pm but a watch remained in effect until around 9pm.
Bluewater Power had crews responding to weather-related outages in parts of the city, most notably one affecting over 2100 customers north of Hwy. 402, east of Indian Rd., north to the lake and stretching east beyond Modeland Rd.
Wind gusts brought down tree branches that blocked a portion of Blackwell Rd., and Sarnia Fire & Rescue was warning residents to stay away from downed power lines. They responded to three 9-1-1 calls about trees on fire and hydro lines on the ground.
The temperature at Sarnia's Chris Hadfield Airport climbed to 32 C (90 F) with a humidex of 42 C at 2pm Monday.
A much more comfortable low of 18 C (64 F) is forecast Monday night with the arrival of cooler, drier air.
Sunny skies, northerly breeze, and a high of 25 C is forecast for Tuesday.
