A thunderstorm over Hillman Marsh. (File photo courtesy of Robert Longphee)

UPDATE: Thunderstorm Watch Ended For Sarnia-Lambton

Some heavy thunderstorms developed across the region Wednesday afternoon in advance of a cold front.

Most of the activity missed Sarnia-city but some storm cells rumbled through central and north Lambton County.

Environment Canada’s thunderstorm watch was elevated to a warning for London-Middlesex.

The weather agency said the greatest threat in the storms was the potential for strong wind gusts up to 100 km/h, hail and locally heavy rain.

The watch for Sarnia-Lambton ended before 5pm.

It’ll be considerably cooler Thursday with northerly winds and a high of 22 C (72 F).