Another round of pre-dawn thunderstorms for Montreal

Thunderstorms moving away from Montreal towards the northeast early Tuesday morning. Despite the cooler temperatures at the surface, warm unstable air moving in from the south has generated numerous storms this week in the St. Lawrence Valley. (Valley Weather Photo)

I was dodging lightning strikes for the third time this week in Montreal while walking my pup during the pre-dawn hours Thursday morning. Another round of storms swept across the region, accompanied by frequent lighting and brief, but heavy rainfall. 

The scenario has been much the same all week here in the St. Lawrence Valley, a warm front lifting into the region, while cool northeast winds supply colder temperatures at the surface. The instability has resulted in the storms firing up, as they did Sunday and Tuesday mornings. Thunderstorms are not that uncommon in late April, but the timing of the storms is a little unusual.

While very warm air has surged into parts of New York State and southwestern Ontario, temperatures have remained quite cool here in Montreal.

Radar image of southern Quebec showing clusters of storms sweeping across the Montréal region during the pre-dawn hours Thursday morning. Nocturnal storms are not all that common in Montreal in the spring, yet this is the third time this week.

The heavy rainfall the has fallen this week, added to an already impressive total for April. The month ended with 142mm of rainfall at Trudeau Airport, well-above the normal value of  82mm. Add to that 26cm of snow, which is double the normal, and it was definitely a wet month.

As we move forward this week, skies should clear out for Friday, with milder high temperatures close to 20C (68F). The weekend looks a little unsettled again, as warmer air will try to take a run at the region. Expect some shower activity, with perhaps a rumble or two of thunder. Next week, much the same, warmer, more humid and more thunderstorms.

Perhaps we are getting an early preview of what the summer of 2024 might look like. Time will tell.