Whatcom’s summer has been free of wildfire smoke. That’s about to change
A late-summer heat wave could mean near-record temperatures and wildfire smoke this weekend in Bellingham and lowland Whatcom County.
High pressure over Western Washington will send daytime highs into the low 80s, prompting a fire weather watch for the region from Friday, Sept. 9, and Saturday, Sept. 10.
That means that winds are expected to shift, bringing smoke from wildfires in British Columbia and Eastern Washington, including the Chilliwack Complex of fires burning in the North Cascades National Park east of Mount Baker.
Whatcom County residents should be prepared for the possibility of unseasonably warm weather and smoky skies, said Jake DeFlitch, a meteorologist at the National Weather Service in Seattle.
“It’s a concern in these sorts of patterns. It’s something we’re monitoring for sure,” DeFlitch told The Bellingham Herald.
High pressure will change the cooling ocean breezes to a northern and easterly flow, he said.
Saturday is expected to be the warmest day, with a forecast high of 82, some 12 degrees above the normal high of 70.
The record for the date is 85, set in 2020.
“Obviously the concern will be ongoing wildfires bringing smoke over to the west side. It easily makes it down that way with a light easterly flow,” DeFlitch said.
Friday through Sunday, Sept. 11, brings a “heightened possibility” of smoke, DeFlitch said.
But some computer forecasting models, including those published by the Washington State Smoke Blog and FireSmoke Canada, a Canadian fire weather forecasting agency, show smoke wafting over western Whatcom County starting Thursday afternoon, Sept. 8.
Officials at the Northwest Clean Air Agency are monitoring weather conditions closely, said spokesman Seth Preston.
“At this time, it is difficult to determine how severe smoke impacts may be,” Preston told The Herald in an email.
“Smoke coverage and severity will depend largely on fire activity before and during the arrival of the high-pressure system. The Brush Creek 2 and Boulder Lake fires, impacting North Cascades National Park and Mount Baker National Forest respectively, will be two of the most local wildfire threats that could influence smoke production. The combined coverage of these fires is over 1,000 acres,” Preston said.
A wind shift Tuesday, Sept. 6, sent air quality in Bellingham and around Kendall briefly into the moderate range, according Northwest Clean Air Agency sensors.
Washington State Smoke Blog forecasts show air quality in the moderate range for western Whatcom County on Thursday, and worsening to unhealthy for sensitive people on Friday.
Cooling ocean breezes should return Sunday, according to weather forecasts.
“Conditions are expected to improve around Monday or Tuesday, as the high-pressure system moves east and a low-pressure system makes its way on shore. The low-pressure system will bring a return to a more westerly airflow to help dilute smoke and ultimately blow it to the east. There will also be a return to more seasonal temperatures as the low-pressure system moves in,” Preston said.
