Steamy smoky forecast for Montreal

Another smoky sky over Montreal on Friday morning. Smoke from Ontario and Manitoba fires will make for poor air quality through Saturday. A smog warning has been posted for Montreal. The AQI (Air Quality Index) for Montreal at 6am Friday morning ranged from 85 to 113 across the island. This is at a level considered unhealthy for sensitive groups. (Valley Weather Photo)

Smog Warning in effect for metro Montreal. Expect poor air quality today as a result of smoke from Ontario and Manitoba wildfires. Conditions should improve on Saturday.

After a rather cool and at times dismal looking July, the warmest weather of the summer thus far is about to descend on Montreal. Most of July was dominated by a northwest flow aloft in the atmosphere. The result was only one 30C high temperature in Montreal, and only 6 such days since June 1st. We will likely add to that total over the next week or so as warm, humid air is pushed northward along the eastern seaboard into southern Quebec.

We will also have to deal with some smoke from western wildfires. It what has become the summer of the wildfire, we have already had several episodes of dense smoke and will likely have several more before August ends. Hundreds of fires are burning across North America, with the main concentration from B.C. into northern Manitoba and northwest Ontario. That smoke will drift over southern Quebec over the next 24 hours, prompting a smog warning for Montreal and portions of western Quebec and northeast Ontario. Southerly winds should help push the smoke out of our region on Saturday.

The airmass will become rather humid, with the chance for showers and thunderstorms each afternoon from Saturday well into next week. The high temperature in Montreal on Thursday was just shy of 30C (86F). The current forecast calls for temperatures in the high 20s and low 30s through next week. Overnight lows will be very mild, close to 20C (68F) in the city, slightly cooler across the off-island suburbs. This will be the warmest stretch of summer 2021 so far.