A fire weather watch for dry, windy conditions has been upgraded to a red flag warning in an area including the San Gorgonio Pass from early Friday to Sunday evening.
The warning area includes southwest San Bernardino County and all of western Riverside County.
The red flag warning issued Wednesday afternoon Oct. 2 goes from 2 a.m. Friday Oct. 4 through 8 p.m. Sunday Oct. 6, according to the National Weather Service.
"A moderate strength Santa Ana wind event now appears likely for late Thursday night through Sunday," the Weather Service advised Wednesday afternoon. "Northeast to east winds sustained 25 to 40 mph . . . with local gusts as high as 65 mph through and below canyons and passes.
"Winds will peak Friday night and Saturday . . . then diminish Saturday night and Sunday morning."
Specifically named in the red flag warning are the Inland Empire, valleys and mountains of San Bernardino and Riverside counties, including the Mountain Top, Front Country, and San Jacinto ranger districts of the San Bernardino National Forest, and the Coachella Valley.
A red flag warning means critical fire weather conditions are either occurring now or will shortly, the Weather Service advised. A combination of strong winds, lw relative humidity levels, and warm temperatures will have potential to contribute to extreme fire behavior.