A one-two punch of triple-digit heat and lingering wildfire smoke is expected to sock southwest Oregon over the long weekend.

An excessive heat warning is in effect through 11 p.m. Monday. The advisory, which covers Jackson, Josephine, Curry and Douglas counties, comes with daily high temperatures of 100 to 107 degrees and overnight low temperatures as high as 75 degrees.

"We’re going to see some pretty hot temperatures this weekend," said meteorologist Brad Schaaf. "They will be near record in many places west of the Cascades."

For Medford, the heat is expected to peak Saturday with a forecast high temperature of 104 degrees, 6 degrees off the record for that day of 110 degrees set in 1988. On Sunday, the mercury is expected to rise to 101 degrees, about 5 degrees off the daily temperature record that was also set in 1988. A 101-degree is expected Monday, 6 degrees off the 107-degree daily temperature record set in 1955.

That's about 20 to 25 degrees above normal for this time of year.

There is lower confidence in the forecast temperatures because of the unpredictability of the wildfire smoke, which absorbs heat. The heavier the smoke, the more the temperatures could drop. And vice versa.

"If the smoke is thinner or for some reason the wind blows it out of the valley, it will be a lot warmer," Schaaf said.

The smoke from multiple lightning-sparked fire complexes that have burned through hundreds of thousands of acres combined is expected to continue right along with the sweltering forecast. The Chetco Bar fire, which had grown to 131,197 acres Friday, has caused evacuation advisories of Level 1 — "get ready" — to Level 3 — "go now" — for residents across Curry County, with multiple structures destroyed. The fire is 10 percent contained, according to the Incident Information System. An interactive map showing the current advisory levels can be seen at https://goo.gl/keU1PZ.

The Miller Complex, burning in the Applegate 17 miles east of Cave Junction, had grown to 14,939 acres in size and was 40 percent contained Friday.

Residents along Palmer Creek, Kinney Creek and Beaver Creek roads, and those on both sides of Upper Applegate Road from Palmer Creek Road to the Applegate Dam spillway, are under the Level 2 evacuation.

The High Cascades Complex, burning near Crater Lake, was 26,332 acres and 37 percent contained.

Air quality stations in the  Applegate, Ashland, Medford, and Shady Cove have not registered "good" air quality since Aug. 13, according to the Oregon Department of Environmental Quality's Air Quality Index. All air quality monitoring stations in Southern Oregon south of Roseburg registered in the "unhealthy" category between Thursday and Friday afternoons. The "unhealthy" level means the air could have negative health effects for all people.

— Reach reporter Ryan Pfeil at 541-776-4468 or rpfeil@mailtribune.com. Follow him at www.twitter.com/ryanpfeil.