Canada's national weather forecaster says the haze from the B.C. wildfires should clear out of Metro Vancouver early this week -- but that doesn't mean it won't return.
Smoke from the fires in the Interior region made its way into the Lower Mainland over the weekend, prompting an air quality advisory that remains in place as of Monday, Aug. 21. However, the advisory has cancelled for southwestern Metro Vancouver as there has been an improvement in air quality.
Metro Vancouver says "Eastern parts of the region continue to experience the most significant smoke impacts."
The province declared a state of emergency on Aug.18 as powerful winds increased the spread of the wildfires, prompting several more evacuation orders.
The air quality in the City of Vancouver has improved since early Monday morning, but places in the Fraser Valley continue to experience a level 10 or a "very high" risk to health.
Environment Canada Meteorologist Alyssa Charbonneau says air quality should gradually improve across the Lower Mainland throughout the day Monday and overnight into Tuesday morning.
While some places already had a "low risk" to health early Monday morning, such as South Delta and Langley, other areas, such as North Vancouver, saw a "moderate" risk. Places near the water were less impacted, while places further inland saw a higher concentration of haze.
Most of the smoke is expected to clear out of the region by Tuesday morning but there won't be a "sudden shift" in conditions. Instead, outflow winds from the west will produce a "gradual transition" to better air quality, Charbonneau explained.
"From here on out gradual improvement through [Monday] and [Tuesday]. By tomorrow morning there is a low-risk [air quality health index] level expected across the Lower Mainland and the Sea to Sky region," she added.
Metro Vancouver weather forecast includes a shift to a cooler, possibly western pattern
A shift is also expected in the Metro Vancouver weather forecast, as temperatures drop down a few degrees overnight Tuesday with a 40 per cent chance of showers. The cooler, possibly wetter pattern may continue through Thursday but temperatures are expected to climb back up heading into the weekend.
Temperatures are expected to climb to a high of 25 C Friday and 27 C Saturday, according to V.I.A's Downtown Centre Weatherhood station. Similar temperatures are also expected in the Mount Pleasant and Granville Island neighbourhoods.
Weatherhood provides detailed weather data for neighbourhoods across the Lower Mainland and elsewhere in B.C. You can also toggle the forecast to give air quality numbers.
The kind of haze that settled over Metro Vancouver this past weekend might return to the region over the weekend or next week, depending on the behaviour of the wildfires.
While Environment Canada is fairly confident most of the smoke will clear out of the region early this week, there is no guarantee that it won't come back once temperatures climb back up and the wind dies down. Similarly, an increase in the size of the fires would produce more smoke in the atmosphere that could make its way into the Lower Mainland," Charbonneau described.
"As long as we have the fires across the southern part of B.C., any time the winds shift it could come back."
