If you’re in southern Ontario and are planning to have a mid-August barbecue, Saturday will be your day to do it as torrential rains threaten to turn Sunday into a washout.
An active and humid airmass south of the border is forecast to move northward into southern Ontario on Sunday morning, along with a low-pressure system that may trigger widespread rain and possible thunderstorms.
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Being at the cottage in northeastern Ontario won’t spare you from the rainy weather, either, as a secondary low is expected to move across the region and also bring heavy rain.
Flood-stricken regions could see heavy to torrential rainfall Sunday
Two weeks after the widespread back-to-back flooding in the Niagara region, where over 250 mm of rain fell between two separate storm events in under one week, and folks are still cleaning up from the devastating damage. Curbs in St. Catharines continue to be filled with wrecked furniture and flooring as basements remain uninhabitable.
As of Aug. 14, St. Catharines remains in a state of emergency as cleanup from the flooding continues. But even as repairs are made, the emotional and physical scars still linger, and any rain in the forecast has residents understandably on edge.
Rainfall is forecast to move into southwestern Ontario and intensify by early Sunday afternoon, impacting the Windsor-Sarnia-London corridor.
By mid-afternoon, the rain and embedded thunderstorms are forecast to lift toward the Golden Horseshoe, bringing heavy to torrential rainfall into Hamilton, the Greater Toronto Area, and Niagara region.
Atmospheric moisture is expected to be high across southern Ontario, bringing the humidex up to the high 30s to low 40s. This will also be the main driver for the torrential rain threat through the afternoon and evening hours on Sunday.
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10-20 mm of rainfall is forecast across the Golden Horseshoe through Sunday, but we could see 30-50+ mm of localized downpours under embedded thunderstorms, some of which may be severe.
There is still some uncertainty in forecast models, however, regarding the exact storm track and location of the heaviest rain. These models should become clearer in the next 24 hours, and the forecast will be updated accordingly.
Stay with The Weather Network for the latest updates and information on your weather across southern Ontario.
WATCH: Over 250 mm rain flooded this Niagara community in under a week