SAN FRANCISCO (CBS SF) — With memories still fresh of the devastating lightning complex fires of 2020, the National Weather Service has issued a red flag warning for the Santa Cruz Mountains and the East Bay and North Bay hills beginning late Sunday morning and lasting through Monday afternoon due to the threat of dry lightning .

A weather system will be moving through the San Francisco Bay Area from Sunday until Monday morning, carrying with it a chances of thunderstorm activity.

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“Thunderstorms will be a mix of dry and wet, but given how dry the fuels are any lightning strikes will be problematic,” the weather service warned. “The threat for thunderstorms diminishes Monday afternoon as the moisture moves northward.”

While the weather conditions were not expected to be as severe as in the fall of 2020, any lightning strike in the tinder-dry hills could spark a fast-moving wildfire.

In 2020, the region was coming off a severe heat wave that helped stoke the ferocity of the lightning storms. Over a four-day period, more than 12,000 lightning strikes were recorded in Northern California. Those lightning strikes sparked up to 585 wildfires, burning more than two million acres.

Wildfires burned thousands of homes, claimed dozens of lives and charred woodlands, forests and wine country vineyards, leaving an ugly scare visible from space.

This year a lack of rainfall over the last nine months has led to excessive or extreme drought conditions. There simply is no moisture in the hills.

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“Recent hot and dry conditions have created very receptive vegetation to new lightning fires,” the weather service warned. “New fire starts may combine with strong outflow winds to cause a fire to rapidly grow in size and intensity before first responders can contain them.’

Appearing on the KPIX 5 Morning News, Cal Fire Battalion Chief Jon Heggie said his agency was on alert.

“We are bringing in extra staff,” he said. “We are preparing prior to the event so we are insuring we have all our resources in position and really watching that weather closely to insure we know where those fires have the potential for starting.”

“The concern is the strikes in the higher elevations, where the fuels are a lot heavier,” said Cal Fire public information officer Paul Lowenthal. “We’re looking at brush, timber. That’s the stuff that is critically dry right now and that’s where our potential is a lot higher.”

For about three years, California was hit by a series of large fires, often propelled by wind events. The threat of lightning poses different challenges.

“The difference between a dry lightning event and a wind event is, obviously, with the wind … they are out of the northeast and pushing those fires to the south-southwest,” Lowenthal explained. “That’s what I’ve seen locally time and time again since 2017. The incidents involving lightning are a little more unpredictable. We’re obviously never really sure where the lightning’s going to strike. We do know that they are typically accompanied by a lot of erratic winds as those fronts move through.”

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Firefighters are asking everyone to remember the lessons learned in recent years and start thinking about emergency plans.