You're clinging to a detail and missing the crushing point. Here it is.
. . . Curiously, the authors ignored the official NOAA data and instead used an unofficial dataset that appears to better suit their argument. Even their cherry-picked dataset, however, contradicts their claim. Does Figure 3, below, look like a 30% decline to you? Take a look at how consistently autumn rainfall has been increasing during the past 30 years. Only by cherry-picking an abnormally wet starting period can a declining trend be argued. And even with the cherry-picked start date, this sure doesn’t look like an ongoing crisis of declining precipitation.
[Figure 3: This chart in the authors’ paper shows rainfall has been steadily increasing during the past 30 years, since 1990. Even starting their data during an abnormally wet period and not including the very wet autumn of 2019, the data do not support the claim of a 30% decrease in precipitation. Source: Environmental Research Letters, Accepted Manuscript, March 26, 2020 (Michael Goss et al 2020 Envir. Res. Lett. in press, Climate change is increasing the risk of extreme autumn wildfire conditions across California - IOPscience)] . . .