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Saturday: Warm, muggy conditions increase the risk of a storm with heavy rain
Good parts of southern Ontario and Quebec are under heat warnings as temperatures are expected to reach the 30s this weekend with overnight temperatures not falling any lower than the low to mid 20s. offering little relief at night. Humidex values are expected to reach the low 40s. As the heat and humidity increase, so do the chances for thunderstorms. A cold front positioned across northeastern Ontario and central Quebec on Saturday will bring a number of storms to the area. As for southern Ontario, there will be no significant activation in the region. However, due to the hot, soupy air mass, there is a possibility of rising air, heavy rain or thunderstorms. Most of the day, however, will remain dry.
Sunday: Heat continues, higher threat for storms with a chance of heavy rain
On Sunday, a cold front will track south through the late morning and early afternoon, bringing more chances for thunderstorms to Central Canada. Any storms that develop will have the potential to suck up copious amounts of tropical moisture into the atmosphere, causing very heavy rainfall locally as they drift eastward. There will be a risk of localized flooding. In addition, storms may also produce locally gale-force winds. As storm arrivals will reach eastern cities and the Montreal area during peak daylight hours, the presence of more instability will allow for some severe storms across the regions, extending westward into southeastern Ontario. However, the threat of storms will be localized and not everyone will see them or rain. MUST READ: Your Mid-Summer Guide to Lawn Care Products Beyond the weekend, active weather will continue into early next week. A developing low pressure system early Monday into Tuesday will allow more widespread rain across southern Ontario and Quebec. Also, the extreme heat and humidity will subside by mid to late next week.
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Stay tuned to The Weather Network for the latest forecast details for southern Ontario and Quebec. Thumbnail courtesy of Cathy P., taken in Wilmot, Ont.