PG&E is warning customers across its service region of possible power outages in the coming days as worrisome weather conditions move into Northern California.

Temperatures are expected to fall by late Tuesday as a light weather system brings some chances of showers at higher elevations.

Strong winds and low humidity are the biggest problems according to this system. A red flag warning is in effect for the Sacramento Valley and Bay Area from Thursday night through Saturday, according to the National Weather Service.

The high fire danger has led PG&E to designate Thursday through Saturday as days when power shutoffs related to public safety are possible.

Specific addresses where closures could occur have not yet been listed. The counties that could be affected by the shutdowns may vary from day to day, PG&E shows on its PSPS website.

Thursday, Oct. 17. Possible power outages

Alameda, Colusa, Contra Costa, Glenn, Lake, Mendocino, Napa, Shasta, Solano, Sonoma, Tehama and Yolo.

Friday, Oct. 18 and Saturday, Oct. 19 possible power outages

Alameda, Alpine, Amador, Butte, Calaveras, Colusa, Contra Costa, El Dorado, Fresno, Glenn, Lake, Madera, Mariposa, Mendocino, Merced, Monterey, Napa, Nevada, Placer, Plumas, San Luis Obispo, Santa Barbara, Shasta , Sierra, Solano, Sonoma, Stanislaus, Tehama, Tuolumne and Yolo.

Sunday, Oct. 20. Possible power outages

Alpine, Amador, Butte, Calaveras, Colusa, El Dorado, Fresno, Glenn, Lake, Madera, Mariposa, Mendocino, Napa, Nevada, Placer, Plumas, Shasta, Sierra, Tehama and Tuolumne.

PG&E said there are no shutdowns planned for Tuesday and Wednesday.