Aug 18, 2023
An upper-level low pressure system just off the California Coast and the subtropical high pressure system over the southern Plains led to strong southerly flow across southern California. This helped transport higher moisture content northward with precipitable water values reaching above 1.5. This led to moderate to strong instability across southeast California with MLCAPE values of approximately 1500-2000 J/KG. A thunderstorm complex developed across western portions of Joshua Tree National P
Source: NOAA National Weather Service Storm Events Database (event 1126215). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in Riverside County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.