Throughout the morning, dozens of lightning strikes were recorded in the hills around Santa Cruz, Santa Clara, Contra Costa, and Alameda counties, forecaster Diana Henderson said.
The weather forecast had included a chance of thunderstorms, though little or no rainfall had occurred as of this afternoon.
"There's not a lot of moisture reaching the ground," Henderson said.
As of 2 p.m., much of today's weather system had moved inland toward the Central Valley and the Sierra foothills, though the red flag warning will remain in effect for the Bay Area until Thursday morning, Henderson said.
The winds, dry conditions and lightning strikes have prompted Cal Fire to increase staffing in Northern California and warn residents about possible wildfires.
"With the already tinder-dry conditions, this lightning storm system has elevated the fire danger even higher for this week," Cal Fire Chief Ken Pimlott said in a statement this afternoon.
Cal Fire has held all personnel on duty, staffed reserve engines and placed inmate fire crews on 24-hour availability.