Major cooldown and heavy rain will end this first week of September in Ontario
A cold front tracking over the Great Lakes will bring some much-needed rainfall to areas experiencing drier conditions later this week, but with a bit of an autumnal chill, as well
Students across Ontario can expect warm weather to kick off the back-to-school season this week. Temperatures are forecast to reach the mid-20s on Wednesday, with some areas, especially in southwestern Ontario, approaching the upper 20s.
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Scattered showers could develop by Wednesday, however, transitioning into more widespread rain on Thursday. There is also a chance of embedded thunderstorms, alongside some breezy conditions.
As the week progresses, autumn-like weather is expected to settle in. Scattered showers, including lake effect precipitation, are likely from Friday through the weekend. Daytime highs will dip to much cooler levels, as well.
Be sure to stay weather-aware for mid-week rain impacts and prepare for changing conditions later in the week, as well.
Heavy rain and chilly highs to end this week in southern Ontario
Rainfall and cooler temperatures are set to arrive in Ontario this week, with a cold front and a system currently centred over northeastern Ontario making their way south by Wednesday.
Rain is expected to spread from the Lake Huron shoreline into the Greater Toronto Area (GTA) early Thursday morning, progressing into the Ottawa Valley by evening.
The rain will include periods of heavy downpours along with isolated thunderstorms. While northern Ontario may receive persistent rainfall of 50-75 mm, southern Ontario is forecast to see more localized amounts of 10-20 mm under the brief but intense cold frontal rain.
A large upper-level low will usher in a colder air mass from the north heading into the weekend. Daytime temperatures in the GTA are expected to reach the mid to high teens by Saturday and Sunday, with early mornings bringing notably chilly conditions.
Highs will likely be a few degrees below the seasonal average for this time of the year.
Looking ahead, temperatures are forecast to gradually climb back to seasonal averages by the second week of September.
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Be sure to check back for the latest weather updates across Ontario.