Bad ozone danger: Tri-Cities invisible threat
The temperature in the Tri-Cities hit triple digits for the second day in a row Tuesday.
Wednesday might be a little hotter.
The high Monday recorded at the Pasco airport was 100 degrees, and Tuesday it was 102.
The National Weather Service says the temperature could hit 103 on Wednesday.
A heat advisory is in effect until 8 p.m. Wednesday in much of the Mid-Columbia.
Only limited relief from the heat is expected overnight Wednesday, with a low of 67 forecast.
Normal average highs for August are about 89 degrees and normal average lows are about 58 degrees.
Temperatures in the Tri-Cities should cool significantly by the weekend. The high Saturday is predicted to be 83 degrees.
But possible thunderstorms with showers will bring the relief.
The chance of a storm system, possibly with lightning, is 20 percent Thursday night and 30 percent Friday night and Saturday, according to the weather service.
Hot days mean ozone
An ozone alert was issued for Tuesday. However, air quality did not deteriorate to a level that was considered unsafe for vulnerable populations, including children, seniors and those with breathing issues.
Weather patterns forecast for Wednesday could put ozone at a level that again means “moderate” rather than “good” air quality, according to the Washington state Department of Ecology and Washington State University.
Typically, light breezes from north of the Tri-Cities carry pollutants in the air until they dam up against the Horse Heaven Hills, trapping the pollution and baking them in the heat to create ozone.
To reduce pollutants that combine to form ozone, Tri-City areas can take steps such as driving less on hot days and putting off mowing or using gasoline-powered equipment either until evening or until another day.
Barbecuing and gassing up vehicles on hot days also can contribute pollutants.
Smoke from a fire to the north continued to cause hazy skies, but air quality remained rated “moderate” in the Tri-Cities Tuesday.
The smoke over the Tri-Cities is coming from the Williams Flat Fire in Ferry County, not far from Grand Coulee Dam, that started Friday from lightning strikes and had burned nearly 17,000 acres of brush and timber by Tuesday morning. It was just 20 percent contained.
Winds could shift some on Wednesday or Wednesday night, possibly clearing out some haze.