The arrival of a cold front Thursday is bringing long-sought relief from a brutal week-long heat wave.
Environment Canada's heat warning issued June 28 remained in effect Thursday, and the weather agency posted a severe thunderstorm watch over the noon hour for Sarnia-Lambton.
Pop-up showers and thunderstorms over Sarnia and parts of Lambton County, in advance of the cold front, were packing heavy rain and intense lightning.
The stifling heat continued Thursday with the humidex at Sarnia's Chris Hadfield Airport hitting 43 C (109 F) by 11am.
In extreme heat, we're reminded to limit our time outdoors during daylight hours, drink plenty of fluids, avoid any strenuous activity, and stay in air-conditioned areas if possible.
Young children, pregnant women, older adults, people with chronic illnesses, and those working or exercising outdoors are most at risk.
Effects of heat illness include swelling, rash, cramps, fainting, heat exhaustion and heat stroke, and the worsening of some health conditions.
Once the cold front takes hold, it will be considerably cooler.
Gusty northerly winds and a comfortable high of 22 C (72 F) are forecast for Sarnia on Friday.