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Severe Thunderstorm Threat Across Portions of Ontario and Quebec; Isolated Tornado Risk

Thunderstorm Forecast, for Southern Ontario. Issued May 23rd, 2019.
Thunderstorm Forecast, for Southern Ontario. Issued May 23rd, 2019.

We are currently watching the risk for some developing severe thunderstorms across portions of Central and Eastern Ontario, continuing into Southwestern Quebec.


Earlier this morning, we saw a few severe thunderstorms across the Extreme South near Windsor, as forecasted. Now, we look to the second half of the day to see even more severe storms.

Into the early afternoon, scattered showers and non-severe thunderstorms are likely to affect portions of Central and Eastern Ontario from Algonquin to the Kawartha Lakes region. Into the middle of the afternoon, multiple isolated thunderstorms are expected to develop in portions of Eastern Ontario extending from Cobourg to Fort-Coulonge. As these thunderstorms develop, they may become severe in this region.

These thunderstorms will continue eastward further into Eastern Ontario, Southwestern Quebec, and Northern New York state. As these storms approach the Canada-United States border, there is higher confidence in severe thunderstorms, hence, our upgrade to the 'moderate' risk. This risk extends from Prince Edward County to Ottawa and then towards Montebello, Rigaud, and Huntingdon. As these storms continue to travel east into the evening, daytime heating will limit the severe thunderstorm threat into Quebec, hence, the highlighted 'low' risk for Montreal and Sanrevois.

Thunderstorm Forecast, for Southern Quebec. Issued May 23rd, 2019.
Thunderstorm Forecast, for Southern Quebec. Issued May 23rd, 2019.

The main threats in all these storms will be gusty winds over 90km/h, small to moderate sized hail and heavy rain. In the 'moderate' risk or area marked with a '2', an isolated tornado or two can't be ruled out alongside even stronger winds towards 100km/h or higher.

Low risk area (green) or marked with a '1':

Areas from Cobourg extending north towards Peterborough, Apsley, Bancroft, and Petawawa including Fort-Coulonge, Duhamel, Montreal, and Sabrevois. There is some question whether or not this should extend towards Sorel and Stanstead as well in Quebec. We have decided to not include these regions in this risk area although an isolated severe storm may be possible.

Moderate risk area (yellow) or marked with a '2':

Areas from Picton and Prince Edward County extending towards Tamworth, Perth, and Ottawa including everything south of this region. Into Quebec, this includes Montebello, Rigaud, and Huntingdon.

Disclaimer: There is some general questions about whether or not the storms will develop due to cloud cover in the region. If the clouds persists into the evening, the threat across the whole region will be mainly non-severe to low...if the clouds do clear, then the forecast maps throughout this post are accurate.


Environment Canada has issued a severe thunderstorm watch for portions of Eastern Ontario with the mentioned risk of an isolated tornado.


We will be closely watching today!

Please let us know what your experiencing!


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