Wet Saturday for Montreal - smoke moves south

Widespread air quality advisories stretch across central and southern Ontario and most of the northern and eastern United States. Dense smoke from wildfires burning across northwest Ontario and northern Minnesota have resulted in some of the poorest air quality in the world over the last few days. Little relief is in site as winds oscillate the smokey air back and forth across the international border. (NYSDOT)

The big story this week is the widespread forest and wildfires burning across parched regions of northwest Ontario into western and central Quebec. Over 180 fires are burning in Ontario, with an additional 19 active fires in Quebec. The total in Quebec for the season is now at 326, of which 72 were caused by lightning and unfortunately 241 by human activity. The Ontario fires are beginning to threaten communities, with evacuations being considered for residents of at least 15 municipalities. Some rain is forecast for the weekend, but also the risk of lightning which may spark additional fires.

The skyline of Toronto on Wednesday, covered in thick smoke from wildfires burning in northern Ontario. The city is fourth on the list of poorest air quality among major cities worldwide on Friday morning.

The Ontario fires have sent plumes of thick smoke southeast across the Great Lakes and into major cities like Toronto, Detroit and Chicago. Air quality has been greatly diminished across Ontario as well as the northern and eastern United States. Residents were being urged to remain indoors Friday, as trips to the emergency room for respiratory issues have spiked, especially in Ontario, Michigan and New York.

Here in Montreal, we have been spared the smoke as most has drifted south and west of the city. We may see some smoke return on Sunday as winds veer to the west and northwest behind a strong cold front.

Our weather will be sunny and seasonable on Friday, a near-perfect summer day, with a high temperatures near 25C (77F). Clouds will increase after midnight as a strong area of low pressure moves down the St. Lawrence Valley. Showers and thunderstorms are forecast most of Saturday, with 20-25mm of rain possible. A cold front late in the day Saturday may produce some vigorous thunderstorms, but the severe weather threat for Montreal is low at this time. Daytime highs will be near 25C (77F), with overnight lows behind the rain dropping to a comfortable 15C (59F)

High pressure should build back in Sunday resulting in a very pleasant, sunny day. The high will be near 24C (76F). Wildfire smoke may return to southern Quebec on both Sunday and Monday.