Smoke set to return to Montreal for 24 hours

Dense smoke over the St. Lawrence River in Dorion last Sunday, June 25. The smoke is set to return Thursday for at least 24 hours across southern Quebec. (ValleyWeather Photo)

Smog and air quality warnings are in effect across our entire region. Smoke from the Quebec wildfires will return across the Ottawa Valley this morning and into southern Quebec by late in the day. This is in response to an upper level low and cold front moving off to the southeast, and a wind shift to the west and southwest.

The smoke will prevail into Friday, before winds shift back to the south, and the heat, humidity and thunderstorms return for the Canada Day holiday weekend.

Dense smoke from fires burning in central and western Quebec have been settling across eastern North America and observed as far away as Portugal and France. (SOPFEU)

Beneficial rain is falling in Montreal on Thursday morning. While showers and thunderstorms have been occurring all week long, most areas have been spared heavy rainfall. For example, at my home on Ile Perrot, the first rain of the week is finally falling this morning. I have only measured 46.2mm for the month of June, while parts of Vaudreuil had 60mm in just one hour on Monday. Trudeau Airport for the same time frame has reported 67.8mm. These differences are typical of a warm and humid airmass, where thunderstorms can be hit and miss.

Radar estimates show that as much as 100mm of rain fell in thunderstorms in Vaudreuil-Dorion on Monday, producing flash flooding. However, just across the bridge on Ile Perrot, no rain fell until Thursday morning, and even then only a few millimetres was measured. (Ventusky.com)

The smoke was affecting portions of the Great lakes and Midwest on Wednesday, with very dangerous air quality across the region. Toronto has some of the most polluted air on the planet Wednesday, reporting 15 consecutive hours of smoke. Early Thursday, their air quality has improved, while both Ottawa and Montreal are declining. Current readings show and AQI of 73 in Montreal and an unhealthy 156 in Ottawa.

Widespread smoke and haze is set to return to southern Quebec Thursday afternoon. Another upper level low returns over the weekend with more heat, humidity and thunderstorms. (AccuWeather.com)

The smoke will return for approximately 24 hours before retreating back to the northwest by Saturday.

According to SOPFEU, 110 fires are currently burning in the province, 26 of which are out of control. We are in the worst fire season on record here in Quebec, with close to 1.5 million hectares scorched already. (1 hectare equals 2.5 acres). Resources from New Brunswick, Newfoundland, Yukon, Parks Canada, The Canadian Armed Forces, USA, France, and South Korea have been helping Quebec firefighters battle the fires. The current wet weather across portions of the province is lending a much needed helping hand.