Flooding persists after storm system soaks Ontario
Tuesday, May 2, 2017, 6:31 AM - May showers were more like May downpours to start the month in southern Ontario Sunday into Monday, and there's plenty more to come later in the week.
Between those two days, parts of the province picked up dozens of millimetres of rain, particularly heaviest in eastern Ontario and the Niagara Peninsula.
Welland and Ottawa both recorded 66 mm, Trenton crept a little higher with 68 mm. Toronto saw some 41 mm, while parts of the southwest saw around 25 mm, with river and lake levels running high in many communities Tuesday morning.
The system that brought these torrents, a Texas low that moved through the province on its way to Quebec, also brought severe thunderstorms, with watches and warnings in effect along the shores of Lake Ontario at the worst of it.
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Showers are on their way back to the southwest, however, as wraparound from the low pressure centre itself starts to edge through the central Great Lakes region. Tuesday will be another rainy day for many, although with much lesser amounts in the forecast.
The next system to watch
After only a brief period of drier conditions and more seasonal temperatures for midweek, we’ll be watching for the first impacts from our next system on Thursday. Temperatures in the low teens and strengthening east winds on Thursday afternoon will precede the development of widespread rain through the afternoon and evening as the system approaches from the south.
Heavier rainfall continues across the region Thursday night into Friday, with temperatures hanging in the single digits for most. Strong and gusty northeast winds will continue, leading to another chilly, wet, and blustery spring day to end the work week.
The surface low is likely to linger near the eastern Great Lakes into the weekend, bringing showers and unseasonably cool temperatures for Saturday and Sunday. Some elevated spots across southern Ontario, particularly the Dundalk and Halliburton Highlands, may even see wet snow mixing in at times during the weekend.
Blocking high pressure over the North Atlantic will mean this system will be slow to clear the region. Instead, it will develop into a cutoff low that will bring unsettled weather to eastern Canada well into next week.
The forecast will continue to be refined as the event approaches, but widespread totals ranging form 25 to 50+ mm are likely from this slow-moving system through the weekend. Given the recent heavy rains and saturated conditions across the region, this will likely lead to additional flooding concerns as spring rainfall totals continue to mount up.
Check back for updates as we continue to monitor the forecast.