Putting my geologist's hat on, it is certainly plausable that (for instance) the passage of a low pressure system could bring forward an explosive volcanic eruption by a few hours; but extra precipitation reaching a magma chamber, or just lubricating faults around the chamber would be a bigger effect. (realclimate.org)
«In some locations we are storing more water, maybe through extra precipitation, and in some regions, we are losing more water,» Adhikari said. (washingtonpost.com)
Instead this El Niño brought a little extra precipitation to northern California in the form of heavy snow in March 2016, and around 80 % of average rainfall to southern California. (environmentalresearchweb.org)