ONTARIO: Thunderstorm Forecast for Wednesday, August 2, 2023

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NOTE: YOU CAN CLICK ON THE MAP TO OPEN A ZOOMABLE IMAGE WHICH WILL BE EASIER TO READ.

As Wednesday evening approaches, isolated thunderstorm activity is expected to develop over Georgian Bay and Lake Huron. The time frame for these storms is from 7 PM to 12 AM. These storms will then track across the Bruce Peninsula and into the Simcoe County and Muskoka region.

While the overall severe threat is expected to be limited due to the later timing of the storms, there is the potential for a few of them to reach marginally severe levels. Within these storms, we could experience wind gusts of up to 90 km/h, hail up to the size of nickels, and heavy rainfall.

One aspect that warrants attention is an isolated tornado risk. Though not a significant concern, models indicate that any storms developing in this area could pose a slight tornado risk.

Decoding Thunderstorm Forecasts: Threats Over Probability ⚡️🌩️

When it comes to thunderstorm forecasts, there are two distinct approaches:

  • Forecasting the probability of thunderstorms occurring based on storm development.

  • Forecasting the potential thunderstorm threats based on the environment.

Both methods have their merits, but at Instant Weather, we prioritize focusing on the threats rather than just the probability. After all, it's the possible threats that pose a real danger to you.

We achieve this by carefully evaluating the latest model data and assessing the level of threat posed by each type should storms develop in a particular region. This includes the risk of tornadoes, damaging winds, large hail, and flooding.

Our overall severe risk classification comprises 6 categories: non-severe, isolated, slight, strong, significant, and extreme. The final category is determined based on the maximum threat level among all the individual threat types.

The graphic above highlights the risk levels of each threat type and their correlation with the overall severe risk. Minor regional differences exist between Ontario and the Prairies; for example, tennis ball-sized hail is classified as a 'strong' risk in the Prairies, while in Ontario, it's considered 'significant'. This variation results from the higher frequency of large hail occurrences in the Prairies compared to Ontario.

Please note that our forecast map doesn’t focus on probabilities, so we don't guarantee storms for a specific region.

In fact, most locations within a region may not experience a single storm. The localized nature of storm development makes it challenging to predict. Instead, we aim to inform you about the potential threats IF storms develop in a given area, based on the surrounding environment.

For a comprehensive understanding of how widespread an event could be and the potential for a ‘bust’, we encourage you to read the entire forecast discussion.