Some relief from wildfire smoke in Montreal

Haze and smoke lie across the western horizon in Montreal on Monday afternoon. Poor air quality has resulted in widespread weather warnings from Quebec and Ontario southward along the US Eastern Seaboard. Some relief is on the horizon for metro Montreal, but eastern Ontario, including Cornwall and Ottawa, will continue to bear the brunt of some of the worst air quality in the world.

Smog warning in effect for metro Montreal

The air is still thick  with smoke across many parts of western Quebec and southern Ontario, stretching as far south as the Carolinas on Wednesday morning, but some relief is in sight. A stubborn upper level low pressure system retrograding over New England, has brought some light rain and cooler temperatures to many parts of the province. While amounts have been very light, less than 2mm here in Montreal, any rainfall is welcome. The cooler temperatures are helping as well.

The circulation around the low has driven the worst of the smoke into eastern Ontario and western New York state. That region has measured some of the worst air quality in the world over the last 24 hours, with widespread visibilities under a couple of kilometres along with high numbers of fine particulate matter. Levels have been very high in eastern Ontario especially, with very unhealthy to hazardous levels reported.

The smoke and haze caused many outdoor activities to be cancelled in the Montreal region and across western Quebec into Ontario on Tuesday.

The smoke is being generated by nearly 150 active wildfires burning across the province that have consumed nearly 500,000 hectares (1.2 million acres). For may, this is the worst fire season already in Canada, and it certainly has produced some of the poorest air quality at many locations since record keeping began.

While conditions will briefly improve here in Montreal, many other locations will still be dealing with the smoke and extremely dry weather.

Widespread air quality advisories remain in effect on Wednesday. The low pressure in question helping to propel the smokey air southward, will only drift eastward very slowly, persisting into Friday. By the weekend, high pressure will attempt to clear skies out, and we may see a break from the smoke.

We need rain. The showers expected this week are forecast to produce 5-10 mm of rain in the Montreal region, but much more is needed to break the dry almost drought-like conditions across the southern and western portions of the province.