Environment Canada issued a heat warning for London and its surrounding counties, and Friday afternoon brought watches and warnings of more active weather.
The weather authority issued the heat warning late Thursday, as a system moved in forecast to bring humidex values near 40 C Friday afternoon.
Also Friday, severe thunderstorm watches and warnings were put in place across southwestern Ontario, with active weather expected to continue into the evening hours.
Forecasters have been calling for the possibility of damaging wind gusts, large hail and torrential rain, as well as the possibility of isolated tornadoes.
A cold front is forecast to move into the region Friday night, bringing temperatures in the low 20s.
For up-to-date watches and warnings visit the Environment Canada website.
Reminder about safety during hot weather
The extreme heat may prove most dangerous to older adults, infants, children and those with chronic illness and Environment Canada recommends people drink plenty of liquids to combat dehydration.
On Thursday, the Middlesex-London Health Unit issued the summer's second extreme heat alert for Friday.
In a statement, Iqbal Kalsi, manager of environmental health, said “The summer of 2014 has been largely free from the kind of hot, hazy and humid weather we usually see in the Middlesex-London area, so it’s important to remind people of the steps to take to stay healthy when the temperatures climb.”
Anyone experiencing heat-related symptoms should seek assistance, for more details on what to look for visit the health unit's website.
