ONTARIO: Thunderstorm Forecast for Thursday, June 8, 2023

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Isolated pop-up thunderstorms are possible during the afternoon and early evening on Thursday across Southern Ontario. While these storms are expected to be quite weak, they could still produce the occasional lightning strike which could potentially start new wildfires. There are also some indications that the environment is favourable for the development of funnel clouds. Especially around the shoreline of Lake Ontario and Erie. Funnel clouds usually don’t present a risk, but in rare cases, they could touch down and become a landspout tornado.

Landspout: A landspout is a type of tornado that forms under a weak thunderstorm. Unlike traditional tornadoes, which develop from supercell thunderstorms and are associated with a rotating updraft called a mesocyclone, landspouts form from non-supercell storms and do not have a mesocyclone. These tornadoes are generally weaker and shorter-lived than their supercell counterparts but can still pose a threat to property and life, with wind speeds occasionally reaching up to 160 km/h.

ONTARIO: Thunderstorm Forecast for Tuesday, June 6, 2023

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Pop-up thunderstorms are yet again expected in parts of Eastern Ontario around the Ottawa Valley during the afternoon on Tuesday. As we saw on Monday, the main risk will be the lightning that could lead to more wildfires. Otherwise, these storms are expected to remain non-severe.

ONTARIO: Thunderstorm Forecast for Sunday, May 7, 2023

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Heavy rain is expected to work its way across Southern Ontario starting Sunday morning and continue throughout the day. Within this area of rainfall, there is the potential for a few non-severe thunderstorms to produce isolated lighting strikes, strong wind gusts and small hail.

In addition to this, there appears to be a pocket of instability that will build into Southwestern Ontario towards the later part of Sunday. This may allow for an isolated severe risk if we see storm development take advantage of this energy. However, models are suggesting that the morning rainfall may linger into the early afternoon which would make storm development unlikely.

We are going with an isolated severe risk for this area based on the potential for localized wind gusts up to 90km/h and nickel-sized hail. This may need to be downgraded in the Saturday update if storm development is looking less likely.

STORM TIMELINE

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As for timing, the primary risk will be during the afternoon and early evening hours. The severe threat will be mainly between 2-6 PM for Southwestern Ontario, but these storms will be very isolated (if they even develop) so not everyone will see storm activity.

The non-severe risk will be more widespread during the late afternoon and early evening hours across Central Ontario and the Golden Horseshoe. For Eastern Ontario, the thunderstorm threat will begin by the dinner hour and continue through much of the evening.