Pacific Gas & Electric is preparing to potentially cut power to up to 264,000 Northern California customers mid-week as the forecast calls for desiccating winds that could damage equipment and spark wildfires.

If you figure an average of three people per household — after all, a single customer could be an apartment building with 50 residents — this event could affect approximately up to 792,000 people.

The intentional blackout is tentatively scheduled for portions of 22 counties in the Sierra Foothills, North Valley and North Bay. The preliminary list of counties posted in a press release Sunday night includes: Alameda, Butte, Colusa, Contra Costa, El Dorado, Glenn, Lake, Marin, Mendocino, Napa, Nevada, Placer, Plumas, Shasta, Sierra, Solano, Sonoma, Sutter, Tehama, Trinity, Yolo and Yuba.

More details started to trickle out late Monday morning from local officials and police departments. The Marin County Sheriff's Office confirmed an estimated 23,345 customers (or about 70,000 people) would lose power starting at 4 p.m. Wednesday. It's not yet clear exactly which neighborhoods in Marin will be affected.

The Moraga Police Department announced customers in Moraga, Orinda and Lafayette would be impacted starting at 9 a.m. Wednesday. The department estimated 18,584 metered customers (or about 56,000 people) in those three cities will be affected.

For the full list of cities where PG&E anticipates turning off power, click here.

PG&E forecasters expect windy weather to move out of the Bay Area by 8 a.m. Thursday, at which point they would start turning power back on.

Blustery conditions are expected to develop early Wednesday (Nov. 20) and continue into Thursday morning with sustained winds of up to 25 mph and isolated gusts up to 55 mph in some areas. With little rain falling in California since last spring, vegetation is dry and fires could start easily and spread rapidly. What's more, multiple wind events in October dried out the landscape.

"Average precipitation in the Northern Sierra by this point in November is typically 5 inches; this year, that region has received 0.3 inches of precipitation," PG&E said in a statement. "Temperatures in PG&E’s service territory are 5 to 15 degrees above average for this time of year."

PG&E will begin to notify potentially affected customers this morning by phone, text and email. PG&E is working closely with state, county, local and tribal partners to prepare for the potential PSPS.

The news comes after PG&E cut power three separate times in October to reduce wildfire risk. The utility says that since the last preemptive power outages, their site and call center have been bolstered to handle increased traffic; the PG&E outage site repeatedly went down during previous PSPS events.

Amy Graff is a digital editor for SFGATE. Email her at agraff@sfgate.com.