Environment Canada has extended a Heat Warning initially issued Wednesday, in effect for West Nipissing, North Bay, Powassan, Mattawa and French River.

The national meteorological service says the heat event will continue through Friday as a hot and humid airmass has reached the area and will remain in place through tonight. Maximum afternoon temperatures near 30 C with humidex values near 36 are expected. Overnight minimum temperatures are likely to remain near 18 C, providing little relief from the heat.

A cold front later Friday will bring cooler conditions and lower humidity for the weekend.

Extreme heat affects everyone and the risks are greater for young children, pregnant women, older adults, people with chronic illnesses and people working or exercising outdoors.

Heat warnings are issued when very high temperature or humidity conditions are expected to pose an elevated risk of heat illnesses, such as heat stroke or heat exhaustion.

Please continue to monitor alerts and forecasts issued by Environment Canada. To report severe weather, send an email to ONstorm@canada.ca or tweet reports using #ONStorm.