A significant weather disturbance is forecast to bring heavy rain, strong thunderstorms, and a localized risk of tornadoes to parts of Quebec this Sunday. Accumulations could reach upwards of 50 mm in some areas as a cold-core system interacts with instability in the Saint Lawrence Valley.
The atmospheric conditions expected on Sunday include a cold-air trough and a strong jet stream, which together create the instability necessary for potential supercell formation.
What to expect this Sunday
Residents planning outdoor activities or attending events like the Francofolies should prepare for shifting weather conditions throughout the day. Rain is expected to begin in the morning, starting as relatively light showers before intensifying as the day progresses.
By the afternoon, the atmosphere will likely become more unstable. Meteorologists note that a combination of humidity, temperature contrasts, and upper-level dynamics will support the development of robust storm cells. These could produce torrential downpours and powerful wind gusts, particularly across the southern regions of the province.
The primary concern for public safety lies in the rapid development of these storms. While widespread heavy rain is expected, the localized nature of supercells means that specific high-risk zones remain difficult to pinpoint until the storms are actively forming, necessitating constant monitoring of local weather updates.
Areas at risk and potential for rotation
The south shore of the Saint Lawrence River remains a focal point for potential severe weather. This region is currently identified as having an environment that may allow storms to become locally violent.
Although the probability is categorized as limited, the risk of an isolated tornado cannot be ruled out. Some of the storm cells may begin to rotate, forming supercells capable of producing tornadic activity. Because the exact trajectory of these cells depends on the real-time evolution of the storm system, the specific areas most exposed to this risk remain uncertain until the event unfolds.
Frequently Asked Questions
What is the maximum expected rainfall?
Local accumulations are expected to exceed 50 mm in some areas.
Is there a risk of tornadoes?
Yes, an isolated risk of tornadoes exists in the southern part of Quebec, as some storm cells may develop rotation.
When will the weather be at its worst?
Conditions are expected to become most favorable for robust and potentially violent storms during the afternoon hours on Sunday.
How are you adjusting your weekend plans to account for these weather conditions?
