Above is a table published recently by the NWS in San Diego (credit: NWS San Diego). It shows the observed rainfall at San Diego (Lindbergh), Riverside, and Santa Ana. Rainfall at Santa Ana so far this month is 780% of normal, Riverside 4850% of normal, and San Diego an amazing 5700% of normal, with almost a week to go in the month!
The global image (credit NOAA) found below shows a comparison of the Pacific water temperatures from the record 1997-1998 El Niño, and current water temperatures in July 2015. The darkest red colors indicate the temperatures most above normal.
There is a remarkable similarity for July to the 1997-1998 El Niño event in the equatorial Pacific, and waters are considerably warmer than 1997-1998 in the northeastern Pacific. NOAA climate scientists believe the abnormally warm northeastern Pacific water is related to the Pacific Decadal Oscillation(click link for details) entering a positive or warm phase.
Our recent record rain event could well be related to these warming waters bringing deep moisture from the tropics, in this case assisted by the remnants of Hurricane Dolores.
James K. Purpura
Certified Consulting Meteorologist