The humidity that floats in from the end of June is good here at least until the end of July. This moisture will bring its share of thunderstorms, which are difficult to predict. Better to heed weather warnings, experts say.
“If we look at the statistics, we see that we have not experienced such a wet first half of July since 1953,” says MétéoMédia meteorologist Patrick Duplessis.
The problem is that the moisture makes for frequent thunderstorms, with seven thunderstorms occurring between June 24 and July 21. During the same period last year, it found only one station located at Montreal-Trudeau Airport.
“It takes a lot of moisture to form storm clouds,” explains Patrick Duplessis. Moisture is one of the ingredients for the formation of thunderstorms. »
Thunderstorms are difficult to predict
Other factors that go into the formation of thunderstorms include temperature patterns and wind, at the surface and at altitude. A complex weather event, but above all difficult to predict, says the meteorologist.
“It’s hard to predict locally in Quebec,” notes Patrick Duplessis. Storms are localized. It doesn’t last all day. It is difficult to say exactly when it will strike [quelle ville] It’s going to strike before it’s formed. »
Yet according to a MétéoMédia meteorologist, spotting a storm 24 hours in advance is nearly impossible. So a week ago.
It’s the same story with Environment Canada meteorologist Peter Kimbell. “We have models that help us predict the weather, but the reliability of the predictions decreases over time. Our models have always had difficulty predicting thunderstorms with good reliability. And that continues. We’re making gradual progress, but it’s still a big challenge. »
“We have to Be alert”
Experts say that in an unstable situation, especially for thunderstorms, it is better to rely on weather warnings issued by the authorities. “Storms can be very localized,” explains Patrick Duplessis. Therefore, we must be careful if we do not want to find ourselves in the middle of a flood or in a watershed. There are many ways to get caught in a summer thunderstorm. »
Philippe Cachon, professor of hydroclimatology at UQAM’s Department of Geography, has a similar opinion. “We have to be vigilant. Lake Membremagog is overflowing, Richelieu has never been this high in July in the last 20 years. »
In the context of global warming, the situation should not improve. “We increase the probability of heavy rains and more violent storms, explains Philippe Cachon. The warmer the atmosphere, the more moisture it can hold. And this moisture turns into more rain. »
