Air stagnation advisory posted for urban areas

The National Weather Service has posted an air stagnation advisory for the Spokane and Coeur d’Alene areas through Friday afternoon. A late autumn dry spell is expected to continue through the week. The quiet weather has forced restrictions on burning. The Spokane Regional Clean Air Agency has placed a temporary burning ban on fireplaces and stoves that are not certified for clean burning. The stage 1 burning ban began on Saturday. The agency is asking residents to use clean sources of heat to minimize the health threat from a build up of wood smoke in the air. Forecasters are calling for a mix of sun and clouds with highs in the middle 30s. Lows will be in the lower 20s. Higher air pressure along the West Coast is dominating the weather pattern for now. December normally would see a third of an inch of precipitation in the first four days of the month. Air stagnation advisories were posted for some areas east of the Cascades as early as last week. Until now, Spokane and Coeur d’Alene have been left out of those advisories, but the weather service decided to issue an advisory for today through Friday for all of Eastern Washington and most of North Idaho. Air quality in Spokane was in the low end of the moderately polluted category this morning. Pollution has been trapped in the lower layer of the atmosphere because temperatures at ground level are colder than aloft. This inversion of the air temperature profile inhibits dispersal of pollutants. This morning’s atmospheric sounding showed that the inversion extended about 3,000 feet above the ground. At 1 p.m., it was mostly cloudy and 37 degrees at Spokane International Airport.