First heatwave of the season on the horizon for Montreal

The first heatwave of the season is expected to begin this weekend across southern Quebec and persist into early next week. Temperatures in Montreal are forecast to reach into the middle 30s along with elevated humidity levels.

After a really odd month of May, June will start with a significant heatwave in the near-future for Montreal and most of eastern North America. The data is still being reviewed for May, but it was a month that feature record high and low temperatures. The extreme temperatures officially at Trudeau Airport were 31.5C (89F) and 1.7C (35F). It was a dry month to say the least, only 11.6mm of rain fell, making it the driest May on record for Montreal. You can see it in neighbourhood lawns, which if you are following water restrictions, are turning brown. Some rain is in the forecast both today and again Thursday. The Thursday system will be the leading edge of very warm, moist air, originating form the Gulf of Mexico. We may finally see a decent downpour, with perhaps as much as 25mm (1 inch) here in the St. Lawrence Valley. We really need it.

Once the rain ends early Friday morning, we are looking at at least a 5 day stretch of hot and humid weather. Temperatures will begin the period around 27C (81F), but rise into the low to middle 30s over the weekend and early next week. Humidity levels and dewpoints will be on the rise as well, making it feel rather uncomfortable and sticky through next week. Any relief in the form of showers and isolated thunderstorms may come by late Tuesday.

The combination of high heat and humidity will make it dangerous for many, so now is the time to install your air conditioners, get your pools ready and prepare for extended hot weather.

The location of the three EF-2 tornadoes that occurred on Tuesday, May 25. The data and map are courtesy of Northern Tornadoes Project at Western University.

Quebec Tornadoes

Adding to the strange weather month that May was, is the fact that the province has already recorded 4 tornadoes. Three of them occurred on May 25, well northwest of Montreal near Rouyn-Noranda. The storms occurred early in the evening along a strong cold front. Satellite data shows the first tornado, an EF-2 with 190km/h winds, occurred near Petit Lac Bull at 7:05pm. The second, another EF-2 occurred at Lac Des Deux Cantons, and the final tornado of the day at 8:25pm, was also an EF-2 near Lac Simpson. Quebec averages 4.7 storms for the entire year, with most of the severe weather season still ahead of us.