El Niño - Some Context for California Precipitation this Winter

El Niño - Some Context for Preciptation this Winter

 

The NOAA Climate Prediction Center (CPC) has switched into "El Niño is here" mode, with a  63% chance of a very strong El Niño  (i.e., RONI > +2.0°C) during November-January. But just knowing what the strength of El Niño does not guarantee a particular outcome; it only tips the scale. Looking at past seven strong and very strong El Niño events, at least one year had below normal rainfall in California. (https://www.ggweather.com/ca_enso2026/ca_elnino.html)


And El Niño does NOT necessarily translate to extensive flooding in California.  Of the 13 largest flood damage years since 1950, only 4 have been El Niño years, 4 La Niña, and 5 neutral. And when you look at the Very Strong El Niño of 1997-98, it only ranks at #13, because even though many parts of the state had nearly double their normal rainfall, it was spread over about twice the number of normal rainy days. For example, SF had 47.22” vs a normal of 22.89”, and 119 days vs a normal of 71 days. See https://ggweather.com/enso/calif_flood.htm

Jan Null, CCM
Certified Consulting Meteorologist
Golden Gate Weather Services
Email: jnull@ggweather.com
Web: http://ggweather.com