Thunderstorms are in the forecast for southwest Oregon over the next two days, potentially igniting wildfires in a region that's in the midst of a bout of hot, dry weather.

The National Weather Service has issued a red flag warning that will be in effect until 11 p.m. Tuesday, according to Weather Service officials. The stormy weather is expected to start around 8 to 9 p.m. today, according to meteorologist Charles Smith, and it could stick around through the night.

Most of tonight's activity will hit the Southern Oregon Cascades and east of the Cascades, officials said, though eastern Jackson County from Shady Cove to just east of Ashland are also in the coverage area. Additional thunder and lightning is also possible Tuesday afternoon and evening, the Weather Service reported.

"We have a slight chance for thunderstorms through Wednesday morning as well," Smith said, adding most of the later activity is expected to primarily affect the Cascades.

Recent lightning east of the Cascades has already touched off 15 fires in the U.S. Bureau of Land Management's Lakeview District, according to news release. The largest of those fires, burning east of Highway 31 between Valley Falls and Paisley, had grown to 90 acres Monday afternoon.

High temperatures in the mid- to high-90s are forecast through the weekend in parts of the Rogue Valley.

The Oregon Department of Forestry has three relief engines and additional crews on standby to prepare for any potential lightning-sparked blazes.

"We’ll be on shift longer today and tomorrow," said ODF public information officer Melissa Cano. "We are ready to respond."

Nearly 80 U.S. Forest Service firefighters are already busy with the 1,400-acre Chetco Bar Fire that has been burning in the Kalmiopsis Wilderness for about two weeks. First reported July 12 just north of the Chetco River about 18 miles northwest of Cave Junction, it's believed to have been caused by a "holdover" lightning strike, or a lightning-sparked fire that was slow to start, Cano said.

The fire continues to burn in terrain north of the river consisting deciduous and conifer forest, some of it previously burned. The Little Redwood campground is being used as a campsite for crews and is currently closed to the public.

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