Dec 6, 2018
A moisture plume with a weak atmospheric river arrived on December 5th and brought rain to the region. On December 6th, a strong closed upper level low pressure brought an unstable air mass into Southern California with showers and thunderstorms, especially Orange and San Diego Counties. Rainfall of 1 inch per hour amounts occurred in Costa Mesa and downtown San Diego as well as adjacent cities. The main storm system on December 6th brought widespread rain to the entire region. All mountains and
Source: NOAA National Weather Service Storm Events Database (event 798895). Narrative written by NWS staff at the time of the event.
This event is one of many recorded floods in San Diego County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.