The Bay Area may see some rare summer lightning again early next week. And while it does not yet look like a large lightning event like the one that sparked multiple massive wildfires in the region last August, it doesn't bode well that this is happening again almost exactly a year later.
"A surge of monsoonal moisture is increasingly likely to rotate over the region Sunday into Monday which could lead to elevated convection and potentially dry thunderstorms," the National Weather Service's local bureau reported Thursday on Twitter. "We will continue to monitor this potential scenario closely and share updates as they become available."
They quickly anticipated concerns that this was a replay of August 2020, and explained that this is a different set of circumstances. It's a repeat in terms of "monsoonal moisture," but apparently this situation will not be as dangerous.
A surge of monsoonal moisture is increasingly likely to rotate over the region Sunday into Monday which could lead to elevated convection and potentially dry thunderstorms.— NWS Bay Area (@NWSBayArea) July 15, 2021
We will continue to monitor this potential scenario closely and share updates as they become available. pic.twitter.com/3gDcO1IwkU
The two events should not be compared in terms of expected impacts.— NWS Bay Area (@NWSBayArea) July 16, 2021
Monsoonal surges such at the one forecast for this weekend are cyclical 2-3yr events, while the 2020 event was a unique set of circumstances.
"The August 2020 lightning outbreak that triggered numerous wildfires occurred due to the confluence of monsoonal & tropical influences (remnants of tropical storm Fausto)," the NWS writes. "There are no tropical influences expected with this upcoming monsoonal surge as Felicia is well to the SW."
As this is happening, temperatures are also going to be rising around the Bay, including in San Francisco, where it's expected to warm at least into the 70s by Monday.
Seasonal temperatures expected again today. Temperatures will warm gradually over the weekend. Inland areas have a chance for 80s and a few low-90s.#CAwx #BayArea #CentralCoast pic.twitter.com/9DKzNGplh6— NWS Bay Area (@NWSBayArea) July 15, 2021
The Bay Area remains in an "exceptional" drought condition, according to the U.S. Drought Monitor, and conditions are primed in all parts of the state for devastating and inaccessible fires if lightning decides to randomly strike anywhere.
The August 2020 lightning storms, which struck the Bay Area on August 16 and 17 last year, sparked wildfires in nearly every Bay Area county that would continue burning for over a month afterwards. The LNU Lightning Complex fires in Napa, Sonoma, Solano, and several other counties, ended up being the fifth largest in recorded state history and also one of the most destructive. The SCU Lightning Complex in San Mateo and Santa Cruz counties stands as the third largest in state history.
Photo: Felix Mittermeier