In short, it appears that humans are contributing to the strength of high pressure ridges off California's coast, which will tend to reduce the amount of precipitation in the state. (theguardian.com)
Most meteorologists blame the current drought on a persistent high pressure ridge that has shunted the storms that usually soak California in the winter northward to British Columbia and Alaska. (nar.realtor)
There is a huge High pressure ridge stuck over the western region of the US for a week and looks to last for another week and a half giving record high temps or at least in Phoenix, AZ.. (climate.gov)