The 2026 water year started off wetter than normal for most of CA, with the biggest anomalies in Southern California and the Southern Sierra. The Sierra precipitation indices were 150% to 200% of normal by mid November. Much of Southern California was 300 to 500 percent of normal for the month of November (see below).
Figure 1 - November 2025 percent of normal precipitation estimated by CNRFC.
The soil moisture was also well above normal by mid November for most of the CNRFC area. However, a very dry Thanksgiving through mid December has caused a lot of the soils to dry out. The CNRFC tracks soil moisture using the Sacramento Soil Moisture Accounting Model (SAC-SMA). The image below shows CNRFC SAC-SMA soil states as a percent of average for Nov 20th and Dec 15th (SAC-SMA is the soil model used by the CNRFC). The Southern Sierra and Southern California soil states are generally still tracking above normal, but the northern half of CA and northeast NV have dropped to below average.
Figure 2 - CNRFC SAC-SMA soil moisture model percent of normal for Nov 20th and Dec 15th.
The April-July forecasted runoff volumes began to track downward from mid November through early December due to the dry conditions. This can be seen in the Central Valley Index trend plot:
Figure 3 - April-July runoff forecast trend plot for the Central Valley Index including contributions from Bend Bridge, Oroville, Englebright, Folsom, Millerton, New Exchequer, New Don Pedro, and New Melones.
In general, the April-July runoff forecasts are 75 to 85 percent of average and 90 to 120 percent of median.
Figure 4 - April-July runoff projections for Dec 15th, 2025 as a percentage of average and median.
There has been a slight uptick in seasonal runoff forecasts over the past week as the HEFS ensembles are picking up on the active period ahead. The Climate Prediction Center is indicating a high likelihood of above normal precipitation for CA and NV through Dec 25th. Unfortunately, this increased precipitation activity will be coupled with above normal temperatures, which will dampen the impact on April-July runoff.
Figure 5 - Climate Prediction Center 6-10 day outlook published on December 15th, 2025.
