Northern Sierra Precipitation Tops Seasonal Normal

The 8-Station northern Sierra Nevada (see map) precipitation Index (8SI) has reached a milestone. Rain and snow over the weekend pushed its total since July 1st to 55.71". This is over an inch above normal for the entire seasonal (July 1 to Jun 30) total of 54.52”.  Normal 8SI for the remainder of April plus May and June is approximately an additional 4 inches.

The 5-station San Joaquin Basin Index is now at 39.71" compared to their seasonal total of 42.57" and the 6-station Tulare Basin Index is at 26.00" compared to their full season normal of 30.50".

Jan Null, CCM
Golden Gate Weather Services

Note: There will be a minor discrepancies between these figures and those published by Calif. DWR which uses the Oct. 1 Water Year instead of the historical rainfall season of July 1 to June 30.  And inexplicably DWR also does not use the standard 30-year climatological normal (1981-2010) but rather non-standard average period of 1922-1998 for the 8-Station Index (50.00") and 1961-2010 for the 5 and 6-Station Indices.