● After a five week drought, California has returned to a wet weather pattern.
● Next week’s storms are forecast to double the current Sierra Nevada snowpack
● Outlook for March has tended “dry”, but the water year runoff outlook is trending “near normal”
The 30-day precipitation totals ending February 9th left most of California dry. The last meaningful rain occurred on Jan. 6th.
Figure 1a - 30-day precipitation totals through February 9, 2026. Source: WRCC
Snow Water Content Trends
Dry and warm conditions over the past 5 weeks had dropped the Statewide snowpack from 95% of average (Jan. 6th) to 53% of average (Feb. 9th)
Figure 2a - CA snow water content by region. Source: CA Department of Water Resources
However, with conditions turning wetter and colder, the Snow Water Equivalent (SWE) over the Sierra Nevada (Feather River watershed down to the Kern River watershed) is forecast to more than double next week, reaching over 8400 KAF (KAF = 1000 acre-feet).
Figure 2b - Sierra SWE trend for Feb 11-21. Source: Modeled SWE from CNRFC Sierra watersheds (CSV output)
Water Year/Seasonal Forecast Trends
Trends in the water year forecasts for the Sacramento and San Joaquin Valley Water Resources Index locations have been trending upward the past few days due to forecast precipitation. Today the Sacramento Water Supply Index forecast reached 110% of average, and the San Joaquin Index is at 99% of average.
Figure 3a - Water year forecast trends for the Sacramento Valley Water Supply Index. Source: CNRFC
Figure 3b - Water year forecast trends for the San Joaquin Valley Water Supply Index. Source: CNRFC
Weather/Climate Outlook
Feb. 16-20 is expected to be much cooler and wetter than normal.
Figure 4.a&b - Climate Prediction Center 6-10 Outlooks. Source: CNRFC and CNRFC
Week 2 (Feb. 21-27) is also expected to be wetter and cooler than average. While most of the precipitation is not expected to come from high atmospheric river (AR) conditions (IVT >250 kg/m/s), if you look at the IVT >150 kg/m/s, there are good probabilities of fairly steady moisture impacting the West Coast, including central and northern California, through the end of February.
Figure 4.c&d Center for Western Weather and Water Extremes (CW3E) AR Landfall Tool. Source: CW3E
March Outlook
The outlook for March is trending dry across much of California (though Nevada is near normal), based on the North American Multi-Model Ensemble (NMME). The same is true for the International Multi-Model Ensemble (IMME). This would align well with the general La Nina pattern for California and Nevada precipitation.
Figure 5.a. - Climate Prediction Center NMME precipitation anomalies for March. Source: CPC
Figure 5.b. - Climate Prediction Center IMME precipitation anomalies for March. Source: CPC
Summary
After a bountiful start to the water year, we went through a very dry 30-day stretch. The next two weeks are expected to bring snowpack levels up to near normal. With abundant soil moisture underneath the snowpack, water year runoff is currently expected to be slightly above normal. However, a dry March would bring a declining trend.
WY2024 and WY2025 resulted in near-normal runoff for the Central Valley Water Supply Index (WSI) (WY24=99%, WY25=104%). Even with a dry March we could very well end up WY2026 with a “threepeat” of 3 years in-a-row of near normal runoff, something we haven’t seen happen before (based on WSI records going back to 1906).
Pete Fickenscher, CNRFC
Figure 6. 3-year Central Valley Index Runoff accumulation. Source: CNRFC
