Flash Flood Warning for parts of eastern San Diego County today, 9/9/22. The National Weather Service in San Diego has issued a Flash Flood Warning for parts of eastern San Diego County today, 9/9/22. * Life threatening flash flooding is ongoing or expected to begin shortly due to heavy rain. * Do not drive your vehicle through flooded roadways. * his storm may intensify, monitor local radio stations and available television stations for additional information and possible warnings from the National Weather Service. For updates and locations that may experience life threatening flash flooding which may include: creeks, streams, urban areas, highways, streets and underpasses, visit the National Weather Service.