Humidity will be in the teens to low 20s, he said.
“We should see an improvement,” Mr. Mathews added. “More sunshine will be filtering through the smoke and that is due to the southwest flow beginning to stir the atmosphere. But the air quality is still forecast to be unhealthy.”
In Oregon, a “red flag” warning of dangerous fire conditions remained in effect east of the Cascades, and there was little moisture in the air. But most of the larger fires in the state are burning west of the mountains and the firefighters battling them were expected to be spared the higher winds.
“The strongest winds I have west of the Cascades is generally gusts of around 15 miles per hour today,” said Charles Smith, a National Weather Service meteorologist in Oregon.
But east of the Cascades, there will be higher winds and low humidity, making conditions “more dangerous than usual,” Mr. Smith said. “If there are any new fires they will have a problem in their initial attack,” he added, referring to firefighting.
Idaho is fighting several fires, with one devouring about 70,000 acres.
In Idaho, hundreds of firefighters continue to battle more than a dozen fires burning in steep, dry forests and shrublands.
The largest blaze, the Woodhead Fire, grew to nearly 70,000 acres Monday, forcing the evacuation of about 40 campers and residents in the sparsely populated patchwork of grazing land and National Forest near the Oregon border.
None of the state’s fires compare in size to the megafires ravaging the West Coast, but with resources stretched thin and forecasts calling for continued dry weather, local fire teams were keeping a wary eye on the blazes.