Chance of dry lightning expected for Bay Area.
Forecasters say monsoonal event won’t be on par with one that sparked blazes last August
A surge of monsoonal moisture bringing a chance of dry lightning to the Bay Area is expected to spread through the region Sunday, though the risk of lightningsparked fires like the ones that razed massive areas in 2020 is much different this year, experts say.
The marine layer that has been hanging around the coast for most of the past several weeks, combined with cooler temperatures, should slow significantly the spread of any fires started by the thunderstorms, experts said.
The risks are so much lower this year that “it’s going to be hard to compare these events aside from, ‘It’s lightning,’ ” said National Weather Service meteorologist Brayden Murdock. He said that several factors make the storm forecast this weekend less stressful than last August’s dry lightning strikes.
“We did see rain hit the ground last year, but it wasn’t a whole lot and it was few and far between, and afterwards we had a heat wave, so the fires that started got even drier conditions,” Murdock said Friday. “That’s one of the biggest differences between this year and last — we’re not looking at anything really warming us up, or winds that
could spread (fires).”
Of course, there’s always the chance for lightning-sparked fires, but … “another big difference between this year and last is that we’ve been seeing a fair bit of marine influence the last few weeks — there’s plenty of drizzle on the coast, and the marine layer has gone pretty far inward,” he added.
In an earlier interview, NWS meteorologist Drew Peterson said that “it is possible we could see new fire starts if we do get those lightning strikes. However, we don’t have the same … conditions” as the August 2020 fires, he added, citing the coastal marine layer as well.
Late Friday morning, the weather service issued a fire weather watch for areas of Monterey and San Benito counties and the Los Padres National Forest. The weather service said the threat for thunderstorms will diminish Monday, when the system moves north.
Monsoonal events typically impact the Bay Area every two to three years, Peterson said. They occur when a high-pressure system builds over the Four Corners area, where Ari
zona, Colorado, New Mexico and Utah meet. The system rotates clockwise over the Gulf of Mexico, northern Mexico, Arizona, New Mexico and southern Texas, and sometimes there’s enough moisture for it to reach into California.
“What we’re facing is just one of these cyclicaltype monsoonal events that may generate isolated but potentially scattered highbased thunderstorms,” Peterson said. “And with that, we could see on the order of one to 20 lightning strikes. It could be more or we could see none.”
Peterson said he wouldn’t be surprised if lightning strikes touch off fires, but absent the hot and dry conditions that prevailed during the event last summer, they are unlikely to spread as rapidly.
Murdock stressed that even though conditions may be less dangerous for this particular system, residents must remain on guard amid drought conditions.
“Even though this doesn’t look like it could be as serious as last year, we need to treat it like it is,” Murdock said.
“Be ready, know what your evacuation route is and who you need to listen to, and stay weather-aware.”