Southern Ontario's major weekend warm-up comes with a flood risk
Parts of southern Ontario are under a special weather statement for the potential for heavy rain this weekend. There's even the risk of embedded thunderstorms and localized flooding as temperatures climb
A taste of early spring will spread across southern Ontario this weekend, with temperatures even nearing the 20-degree mark for the first time this year in parts of the southwest.
With the warmth however, comes a rainy catch, as a powerful Colorado low spans much of central and eastern North America.
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The storm will bring a wintry mess to Manitoba and northwestern Ontario, while heavy rain and even thunderstorms threaten parts of southern Ontario as a second low follows quickly into Sunday.
With a risk of thunderstorms, localized flooding is possible with heavier rain totals, especially since the frozen ground has a reduced ability to absorb this rainfall.
This weekend: Surge of mild air brings heavy rain threat with it
A large Colorado low will track into extreme northwestern Ontario by Friday evening. Combined with the influence of a strong centre of high pressure over the Atlantic Ocean, a sharp southerly flow will develop for a big chunk of Ontario.
For southern areas, it will help kick off warm and rainy conditions on Saturday afternoon. A second low will swiftly follow, stirring up more active weather on Sunday, as well.
Southern Ontario will be under an expansive warm sector, raising temperatures into the teens, so precipitation will fall as rain. We will likely see Canada’s first 20°C of the year at times throughout the weekend.
The first round of rain moves into southwestern Ontario Saturday morning, which could have some embedded thunderstorms with it.
As the line of rain moves east towards the Greater Toronto Area (GTA), the rain will start to dissipate, being much lighter and scattered for the GTA through the early afternoon.
Strong southerly wind gusts are expected on Saturday afternoon in southwestern Ontario.
As the Colorado low tracks north, a secondary low will form along the trailing cold front, which will bring in more widespread rain Saturday overnight, and through the day on Sunday.
Localized flood threat with heavy rain, snowmelt, and thunderstorms
Embedded thunderstorms are possible throughout all of southern Ontario Sunday, and could even push into sections of the northeast, as well.
This rain will move into eastern Ontario midday Sunday, and continue through the day and into the overnight hours, before easing Monday morning.
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A widespread 10-20 mm of rain is forecast through the weekend, with locally higher amounts up to 40 mm across the southwest and into the Nickel Belt region.
The rain and milder temperatures will cause additional snowmelt, with the threat for localized flooding, and water pooling on roadways. There's also a risk for ice jams on creeks and rivers.
"The frozen ground has a reduced ability to absorb this rainfall," says Environment and Climate Change Canada (ECCC) in the special weather statement issued early Friday morning.
Another Colorado low is expected next week, but this storm is not expected to be nearly as strong as the impending system. However, it should also have more cold air to work with and bring snow to parts of Eastern Canada.
Stay with The Weather Network for your latest forecast across Ontario.