After spending much of October in well above seasonal territory, the 20-degree days of 2021 could now be in the rear view mirror for Ontario. Widespread rain will mark much of the day on Thursday, with temperatures set to take a significant tumble into the weekend. Though still normal for this time of year, conditions are likely to feel rather cold in comparison to what the region has been spoiled with so far this fall. For some areas, daytime highs will struggle to even climb above 10°C by Saturday, with even the threat for lake-effect flurries over higher elevations. More on Thursday's rainy system and if this stretch of cooler weather is now here to stay, below.
THURSDAY: WIDESPREAD RAIN AHEAD OF TEMPERATURE TUMBLE
We hope you had a chance to nip outside on Wednesday – though not completely shower-free, it was possibly the last in a line of the several 20-degree days this month, and possibly the entire year.
While temperatures will still remain above seasonal, more rain will spread across the region on Thursday, with showers lingering through the afternoon.
As the system's cold front tracks across the south, instability builds, and there will be the risk of thunderstorms into the afternoon as well, some of which could produce locally strong winds, small hail and heavier rainfall amounts.
Though the day won't be a total washout, a widespread 10-20 mm of rain is expected, with closer to 5-10 mm for the 401 corridor.
The gusty, northwest winds will also usher in cooler, fall air in behind the low Thursday night and into Friday morning.
WEEKEND: MUCH COLDER PATTERN TAKES SHAPE, FIRST THREAT FOR LAKE-EFFECT FLAKES
Friday's temperatures will hover close to the seasonal mark, but will feel much cooler compared to the balmy conditions of late.
With the extremely mild Great Lakes and the arrival of colder air temperatures, lake-effect showers will target areas south and east of Lake Huron and Georgian Bay as well.
Some higher elevations of southern Ontario, south of Georgian Bay, may even see some mixing or wet snow in the early morning hours of Friday or Saturday.
The cooler and unsettled weather will persist into the early parts of next week, before a brief bounce back during the middle of the week. Overall, the month of October still looks to tip to the warm side of seasonal.
Be sure to check back for the latest updates on Ontario's fall weather.