At 7:35 p.m. EDT, Environment Canada meteorologists are tracking a severe thunderstorm capable of producing very strong wind gusts, up to nickel size hail and heavy rain. A line of thunderstorms over Lake Huron will reach the Goderich to St. Joseph areas between 7.45 and 8.00 PM then areas extending from St. Joseph across Grand Bend to Sarnia between 8.00 and 8.30 PM. Heavy downpours can cause flash floods and water pooling on roads. Large hail can damage property and cause injury. Strong wind gusts can toss loose objects, damage weak buildings, break branches off trees and overturn large vehicles. Remember, severe thunderstorms can produce tornadoes. Take cover immediately, if threatening weather approaches. If visibility is reduced while driving, slow down, watch for tail lights ahead and be prepared to stop.