While the first half of the construction holiday was marked by periods of heavy rainfall and humidity, the second half will feature cooler air as an aggressive cold front sweeps into the province on Friday.
Environment and Climate Change Canada has issued severe thunderstorm watches for southwestern Quebec.
As a sharp cold front slices into a hot and humid airmass, conditions will be favourable for the development of severe thunderstorms capable of producing strong wind gusts, large hail, and heavy rain Friday afternoon and evening.
While severe storms are possible across the watch zone, the greatest threat for severe weather on Friday will be across the Ottawa Valley and Quebec City regions.
Environment Canada is also warning that severe thunderstorms can produce tornadoes.
Central Canada will see high heat and humidity on Friday. Heat warnings are in effect for parts of southern Ontario as the temperatures are expected to soar into the low 30s with humidex values around 40.
Montreal is expecting a daytime high of 29 C and humidity will make it feel closer to 39.
Behind the passage of the cold front, heat and humidity are expected to drop into the weekend.
Cooler air is expected to linger through the second half of the construction holiday, with daytime highs ranging between 21 C and 24 C. The normal high for the beginning of August is 26 C.
