California Rainfall and Reservoir Updates


Despite recent moderate precipitation amounts across the state (, the rainfall and reservoir deficits continue to grow; well beyond the capability to make up the amounts in a single season. Even after the 1.79 inches that San Francisco has received to date, the total 4-season deficit is currently over 29 inches and will be over 50 inches by the end of the season, if no rain were to fall. (San Francisco normal 22.89", SF record 49.27 in 1861-1862.)

Likewise, the critical 8-Station Northern Sierra Precipitation Index (8SI) currently has a deficit of more than an entire season. 

And these large rainfall deficits are evident in the current levels of the state's reservoirs which have steadily declined over the past 3= seasons and are at just 61% of their average mid-November storage.

Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Twitter: @ggweather