Rain and thunderstorm risk spans southern Ontario Monday
A stubborn, stalled low-pressure system will pester southern Ontario as we start out this new work week across the region
Conditions will remain gloomy and unsettled across southern Ontario to start the week, as a blocking pattern in the upper-atmosphere forces a low-pressure system to spin near the Great Lakes for a little while longer.
Some rain showers in the morning, combined with a storm risk building by the evening, could throw a wrench into travel and outdoor plans on Monday.
DON'T MISS: Blocking pattern to dictate Canada’s weather this week
Keep a close eye on highway conditions and weather alerts in your area as you go through the day.
Storm risk builds Monday as low pressure system stalls over the Great Lakes
A cutoff low is a low-pressure system that stalls out because it’s severed from the jet stream. These systems are responsible for multiple days of gloomy weather—and the occasional strong to severe thunderstorm.
This is the setup we’ve got in place to start the week across southern Ontario as our cutoff low lingers around the Great Lakes.
The uncommon southeast to northwest storm motion pivoting around the nearly stationary low will result in a significant range in accumulation numbers over just a short distance.
Growing instability and ample moisture aloft will introduce the risk for thunderstorms from cottage country to the shores of Lake Erie and Lake Ontario through late Monday afternoon and evening. Given the dynamics at play, these storms could produce heavy rainfall and small hail, especially around Lake Erie.
Temperatures will vary greatly depending on your proximity to the west end of Lake Ontario.
A brisk easterly wind will lead to noticeably cooler temperatures along the western shores.
Tuesday looks to feature better conditions across the Greater Toronto Area (GTA) and Niagara region, as the organized shower activity will persist across northeastern and eastern Ontario.
By Wednesday, the low will depart to Quebec. A band of moderate rain is likely through central or eastern Ontario, though there's still some uncertainty with the timing and amounts there.
A cold front from northeastern Ontario will take quite the bite out of temperatures on Wednesday as well, with places like Timmins going from 21°C to just 7°C.
Rainfall totals throughout southern Ontario will vary significantly over the next couple of days due to thunderstorm activity and showers forming into bands.
General totals of 10-20 mm are a good bet for most communities, with lower totals toward Lake Huron and amounts as high as 40 mm across parts of eastern Ontario.
Cherry blossoms are in peak bloom
Weather plays an important role in the cherry blossom season—both for the flowers themselves, and for folks hoping to see them in all their beauty.
Cherry blossoms in High Park are currently in peak bloom, which is similar to the 2022 cherry blossom season, which saw a peak bloom between May 5-12. This season’s bloom is nowhere near the latest on record, which saw a peak between May 12-21 back in 2014.
The earliest peak bloom on record occurred between April 10-17, 2012, thanks to record warmth early that spring.
Stay with The Weather Network for all the latest on conditions across Ontario.