SAN FRANCISCO – Pacific Gas & Electric Co. reduced the scope of Bay Area customers who could lose power starting Thursday morning in the second time public safety power shutoffs will be implemented this week.

PG&E said Tuesday that customers in portions of 20 counties could lose power starting at 12 a.m. on Thursday but then reduced the scope on Wednesday to around 16,000 customers in 12 counties, including Napa, Solano and Sonoma.

“This potential PSPS event does appear to be weaker than the October 11 event but will still result in critical fire weather conditions across the northern Sierra, western Sacramento Valley and portions of the elevated Bay Area as well as portions of the far South,” PG&E said in a news release.

Winds could reach up to 25 to 35 miles per hour across the North Bay and East Bay hills but the highest peaks could see gusts up to 40 miles per hour, said Anna Schneider, a National Weather Service meteorologist. The stronger winds will be mostly confined to higher elevations Thursday morning and should be gone by Thursday afternoon.

The list of impacted regions and estimated restoration times can be found here.

The power shutoffs are due to a “dry offshore wind event” that is expected to increase wildfire risk in the Bay Area. The shutoffs were announced a day after the utility shut off power for around 25,000 people in 23 counties, including thousands in Alameda, Contra Costa, Napa, Solano and Sonoma counties.

Tuesday, PG&E said it had restored power to “essentially” all of those 25,000 customers.

The National Weather Service issued a red flag warning Sunday, saying that fire danger could be increased due to gusty, northerly winds across the Bay Area. The warning began at 11 p.m. Sunday and ran through 5 p.m. Tuesday in the East Bay hills and valleys and the North Bay mountains. The warning began at 2 a.m. Monday for the Santa Cruz Mountains, interior Monterey and San Benito county mountains and the Santa Lucia Range.

Wind gusts reached 55 miles per hour in Butte County, 52 miles per hour in Shasta and 47 miles per hour in Tehama, according to PG&E.

“We have another round of offshore event and the trough is much more inland than what we saw earlier this week, so the wind will be lighter and confined to higher elevations, mainly the mountains in Napa and Solano counties,” Schneider said. “The one earlier this week moved in Nevada and this one will move to the Idaho and Montana region, so it’s farther away. It won’t be as strong or widespread as we saw earlier.”