Hundreds of lightning strikes sparked across the Bay Area as a low pressure system passed through the region this week, bringing a spattering of rain and a cooldown that is set to end as temperatures heat up again.
Over a 24-hour period from Wednesday to Thursday morning, about 5,000 lightning strikes touched down across the state, according to the National Weather Service.
While it’s not unheard of to have lightning this time of year, “I would say that it doesn’t happen often,” NWS meteorologist Roger Gass said. “We’ve actually had a similar situation last week that brought less in the way of showers and thunderstorms. They were more isolated in nature, but this one basically it outperformed itself.”
Lightning was reported all across California, from the Bay Area and Central Coast to Sacramento and Los Angeles, said Gass. There were 985 strikes recorded in the Bay Area and Central Coast region between late Tuesday night and early Thursday morning, according to a map shared by the weather service Thursday morning.
The map showed large amounts of lightning clustered in Contra Costa and Alameda counties. Strikes were recorded across the entirety of Contra Costa, with the highest concentration in the east side of the county, while strikes in Alameda County were centered almost entirely in the county’s east side.
In Brentwood, in eastern Contra Costa County, some residents found the influx of lightning unsettling, including Mayor Susannah Meyer.
“It’s been so muggy lately, and I saw there was a slight chance of rain, but I didn’t expect a full-on thunder and lightning show,” Meyer said, adding that she was woken up in the middle of the night by “booming” noises.
The storm caused brief blackouts in two Brentwood neighborhoods — Shadow Lakes and Brentwood Hills, said Brentwood Vice Mayor Pa’tanisha Pierson.
Brentwood football coach Jeff Weisinger, who was coaching an Oakley high school Wednesday evening, described the lightning as a “cool light show.”
“We don’t get a lot of (bad) weather out here,” he said. “Sometimes it’s a combination of cool and a little scary.”
Strikes were also recorded in southwestern Santa Clara County, passing up San Jose and with only a handful of strikes in the eastern part of the county.
The lightning skipped the Peninsula almost entirely – save for a single recorded flash in San Francisco, according to the map.
Lightning started four major fires in August 2020, including the August Complex fire — the largest in California history — as well as three other fires that sit in the top 10 of CalFire’s list of the state’s biggest fires ever. A CalFire information page did not indicate any new fire starts thought to be caused by lightning on Thursday.
Officials could not confirm whether a house fire that broke out in Brentwood shortly after midnight Thursday was started by lightning, but Lauren Ono, Contra Costa Fire Protection District public information officer, said lightning was reported in the area around the time the two-story structure caught fire.
The lighting came from a standalone low pressure system off the coast of Monterey, while a cluster of storms brought rain across the Bay Area, said NWS meteorologist Nicole Sarment. The low pressure system traveled up from Southern California and brought monsoon moisture from the sub-tropics, Gass said.
“That’s in part why we have the muggy conditions that really persist into (Thursday) and possibly into (Friday) as well,” Gass said.
South Bay cities such as Gilroy saw the highest concentrations of precipitation, with the area receiving just under an inch of rain Wednesday, Sarment said. Mt. Madonna, between Gilroy and Santa Cruz, received the highest recorded rain level, hitting 1.18 inches.
The low pressure system was still lingering south of the Bay Area on Thursday, bringing rain showers to Monterey County and other southern points, Sarment said.
The weather was expected to heat back up Friday and Saturday, with temperatures rising to the mid to upper 80s in San Jose and the mid 70s in Oakland. Some areas of Contra Costa County could hit the low to mid-90s. The Peninsula’s bayside will warm to the mid-80s while the coastside will hit only the mid-60s.
“The heat will be the notable thing,” Sarment said.
A cluster of rain systems will reach the Bay Area on Sunday and stay through Wednesday, bringing with them a cooldown of temperatures as a system arrives from Alaska. The rain will reach the North Bay Sunday night and spread south beginning Monday, Gass added.
“There is rain expected, … but it’s not going to be non-stop rain,” Sarment said. “We’re not expecting any widespread flooding or anything.”
The rain is expected to bring higher precipitation totals to the North Bay and lower in the South Bay. The storm also is expected to bring cooler temperatures with the rain and cloud cover.
The storms will also bring the possibility of more lightning, but current forecasts only predict that in the North Bay Monday, Gass said.
“It’s going to be cooler conditions, especially since it’s not coming from the south. It’s coming down from the Gulf of Alaska,” Gass said. “This will be a fall-like system.”
