SAN FRANCISCO (CBS SF) — As thousands of firefighters battled one of worse wildfire outbreaks in state history from the shores of Lake Berryessa to the Santa Cruz Mountains, the National Weather Service issued a new dry lightning warning Friday that sent a chill throughout the San Francisco Bay Area.

The current outbreak of fires was sparked to life by two days of raw dry lightning storms that rolled through the area at the start of the week.

The three biggest fire complexes — the SCU Lightning Complex, the LNU Lightning Complex and the CZU August Lightning Complex — have burned more than 500,000 acres, claimed four lives, destroyed houses and other structures and forced thousands to evacuate their homes.

All in the aftermath of the dry lightning storms.

“The challenge we are facing, the fire concentration facing us here in the state, is now disproportionately impacting Northern California,” the governor said at a morning news conference. “And that is because of close to 12,000 lightning strikes that we experience over a 72-hour period.”

Images flooded into social media on Sunday and Monday. Many marveled at the beauty of the storm without knowing the havoc the lightning strike would create.

On Friday, weather service forecasters said conditions were developing that could bring a repeat on this coming Sunday.

“Isolated to scattered dry thunderstorms will develop Sunday afternoon and into Monday morning,” forecasters said in issuing a Fire Weather Watch to begin at 11 a.m. Sunday. “An additional round of thunderstorms are expected to arrive later Monday into Tuesday. Dry thunderstorms may become wet as the event progresses.”

Forecasters said the strikes could give rise to ‘sleeper’ wildfires.

“Lightning will likely spark new fires across the region, including remote areas,” the weather service said. “Wildfires in remote regions may not become apparent until warmer and drier conditions allow them to grow.”

Newsom said much of the damage currently being done to the state came from ‘sleeper’ wildfires.

“Just a day ago,” Newsom told reporters. “I announced that we are struggling to arrest the needs of suppressing some 376 fires in the state. That number has grown to about 560 fires in the state of California. You had a lot of sleeper fires. This we anticipated as the smoke cleared and as our reconnaissance efforts increased.”