Hot and humid weather persists across southern Quebec

The hot and humid weather during the past week across our region has been broken at times by occasional showers, thunderstorms and even rainbows!

Heat Warning in effect for southern Quebec

Widespread heat warnings and advisories are in place for much of southern Ontario and Quebec as well as a large part of the northern and central US, including both the Champlain and St. Lawrence Valley. The combination of very warm temperatures and high humidity will push humidex values into the upper 30s for many, with even a few 40C readings. Montreal managed a humidex reading of 40C (104F) on Wednesday afternoon. The current heatwave included an all-time record high of 35.9C (96.7F) at Gaspe Airport on July 29. This surpassed the previous all-time high of 34.8C (94.6F) set in 1983. Records at that locations date back to 1915.

It has been a very humid stretch of weather across most of eastern North America over the past week, with humidex values approaching 40C in Montreal. Over the past week, daytime highs have been at or over 30C (86F), with the exception of Wednesday, when clouds and thunderstorms managed to keep the high at 28C (83F). The trend will persist into the upcoming weekend, with highs near 32C (90F) Friday, and close to 30C both Saturday and Sunday.

The warm, humid airmass will generate a few isolated thunderstorms Friday afternoon, just as it did Thursday. However, most of the region will remain dry. Overnight, conditions will very warm and muggy, with some valley fog possible, and lows near 22C (72F). 

We an expect a very warm and humid weekend. A few weak low pressure troughs may generate some scattered showers and thunderstorms. That threat will increase Monday, as a stronger cold front arrives from Ontario. We can expect an increase in aerial coverage of showers and storms, with a increase chance of heavy rainfall. Cooler and finally some less-humid weather is expected by midweek next week.

It has been a very wet summer here in eastern Canada. Many region including Montreal, Toronto and especially parts of Vermont have been hit with significant flash flooding. In the case of northeast Vermont, some locations have had major flooding on more than one occasion. Rainfall totals for the July included 124mm at Trudeau Airport, with 215.4mm at Pearson Airport in Toronto.

I see no end in sight for our wet summer, especially with the expected increase in tropical activity during August and September.