Yet another monsoonal surge could soon cause dry lightning in Bay Area amid wildfire concerns FacebookTwitterEmail There's a slight chance of lightning across Northern California early next week. CochiseVista/Getty Images/iStockphoto Yet another surge of monsoonal moisture is coming to the San Francisco Bay Area and the Central Coast, prompting concerns of dry thunderstorms in an already-intense fire season. The moisture will "advect northward" from the desert Southwest starting Monday, according to a report from the National Weather Service Bay Area, and will likely run through Tuesday. "This mid-level moisture will potentially interact with increased instability to produce isolated to scattered high-based rain showers and/or thunderstorms," reads the notice.