Ranking the California Precipitation Pattern

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Discussion: Except for northwest California the deep layer (10-200 CM) soil moisture is near normal for central and southern California. Deep layer soil moisture deficit is required to combine with surface (0-10 CM depth) to cause intense drought or flash drought conditions. The lack of deep soil moisture deficits in Central and South California is not surprising. Deep soil moisture mirrors the long-term climate pattern. So far in 2019, monthly precipitation ranks across California have been wet to very wet 5 of 10 months (Fig. 1). November is also likely wetter than normal. Very dry climate across California was observed in 2014 and 2015 followed by beneficial wet conditions in 2016 and 2017 while 2018 was dry (Fig. 2). 2019 is likely slightly wetter than normal.

The issue arises due to 2 to 4 times that of normal precipitation the past 7 days across central and southern portions of California and a prohibitive 7-day quantitative precipitation forecast (Fig. 3). A drought condition in California projected by NOAA/CPC is unlikely.

Fig. 1: Monthly precipitation ranks for California based on a 125 year climatology.

Fig. 2: Annual precipitation ranks for California 2014-2018.

Fig. 3: NOAA/CPC 7-day quantitative precipitation forecast indicates heavy amount across California.