Here is the first Water Supply Index (WSI) forecast for the season from the Department of Water Resources:
A Water Year 2016 Water Supply Index (WSI) forecast for conditions as of December 1, 2015 is posted at http://cdec.water.ca.gov/cgi-progs/iodir/WSI.2016 .
The WSI forecast is based on the precipitation and flows through November 2015 and can be summarized as follows:
Sacramento River Unimpaired Runoff Water Year Forecast (50 percent exceedance)
12.8 MAF (70 percent of average)
Sacramento Valley Index (SVI) (50 percent exceedance)
5.3 (Critical)
San Joaquin Valley Index (SJI) (75 percent exceedance)
1.5 (Critical)
Runoff:
Unimpaired flows for the 2015-2016 water year have run at the following rates of average:
Region October-November Runoff (%) November Runoff (%) Sacramento Valley Index (4 rivers) 43 34 San Joaquin Valley Index (6 rivers) 52 56 Tulare Lake Basin (4 rivers) 48 52
Precipitation:
Precipitation for the 2015-2016 water year accumulated at the following rates of average:
Region/Index WY accumulated precipitation (%) through November 30, 2015 Sacramento River 72 San Joaquin River 114 Tulare Lake 157 Statewide 82 Northern Sierra 8-Station Index 51 (4.9 inches) San Joaquin 5-Station Index 100 (7.0 inches) Tulare Basin 6-Station Index 114 (5.1 inches)
Snowpack:
The snowpack as of the morning of December 8, 2015 stands at the following (based on snow sensors):
Region Snow Water Equivalent (inches) % of Average (Apr 1) % of Average (Dec 8) Northern 3.8 13 64 Central 3.4 11 52 Southern 2.6 10 56 Statewide 3.3 12 59
Weather and Climate Outlooks:
The 6-day weather forecast indicates productive storm systems on days 2 and 3 for the Sierras. The North Coast is expected to receive up to 7 inches of precipitation by the end of the period with day 2 being the wettest. The Sacramento River region is expected to receive up to 4 inches of precipitation by day 3, then 1 inch of precipitation returns on the last day of the period. The San Joaquin River region is expected to receive up to 2.5 inches on day 3 with up to 1 inch of precipitation returning the last day of the period. The freezing levels for the North Coast and Sacramento River region remain over 10,000 through day 2 then drop to 6,000 feet by day 3 and oscillate to 5,000 feet by the end of the period. The freezing levels for the San Joaquin River region remain over 10,000 feet through day 3 and oscillate to 7,000 feet by the end of the period.
The NWS Climate Prediction Center (CPC) one‐month outlook for December, valid November 30, indicates equal chances of above normal or below precipitation for the entire state with the exception of a small sliver along the California-Nevada border north of Lake Tahoe. The same outlook predicts above normal temperatures for the western half of the State and equal chances of above or below normal temperatures for the eastern half.
The CPC three‐month (December‐January‐February) outlook, posted November 19, indicates above normal precipitation for the entire state with the exception of a small area near the California-Nevada-Oregon border. The same outlook predicts above normal temperatures for the entire state.
El Niño conditions are present. Positive equatorial sea surface temperature anomalies continue across most of the Pacific Ocean. El Niño will likely peak during the Northern Hemisphere winter 2015-2016, with a transition to ENSO-neutral anticipated during the late spring or early summer 2016.
Next Update:
The next WSI forecast for conditions as of January 1, 2016 will be available on January 11, 2016. If you have any questions regarding this forecast, please contact a member of the Snow Surveys staff.
Important Links:
Full Natural Flow Data:
- Daily FNF: http://cdec.water.ca.gov/cgi-progs/snowsurvey_ro/FNF
- Monthly FNF: http://cdec.water.ca.gov/cgi-progs/snowsurvey_ro/FNFSUM
- Seasonal FNF: http://cdec.water.ca.gov/cgi-progs/snowsurvey_ro/FLOWOUT
Precipitation Data:
- Latest Northern Sierra 8-Station Precipitation Index: http://cdec.water.ca.gov/cgi-progs/queryDaily?s=8SI&d=today
- Latest San Joaquin 5-Station Precipitation Index: http://cdec.water.ca.gov/cgi-progs/queryDaily?s=5SI&d=today
- Latest Tulare Lake Basin 6-Station Precipitation Index: http://cdec.water.ca.gov/cgi-progs/queryDaily?s=6si&d=today
Snow Data:
- Latest Snow Sensor Report: http://cdec.water.ca.gov/cgi-progs/snow/PAGE6
- Latest Statewide Summary of Snow Water Equivalents: http://cdec.water.ca.gov/cgi-progs/snow/DLYSWEQ
Extended Regional Forecasts:
- California Nevada River Forecast Center 6 Day QPF and Snow Level Forecast: http://www.cnrfc.noaa.gov/awipsProducts/RNOHD6RSA.php
- Climate Prediction Center One-Month Outlook Forecasts: http://www.cpc.noaa.gov/products/predictions/30day/
- Climate Prediction Center Three-Month Outlook Forecasts: http://www.cpc.noaa.gov/products/predictions/long_range/seasonal.php?lead=1
- U.S. Seasonal Drought Outlook: http://www.cpc.ncep.noaa.gov/products/expert_assessment/sdo_summary.html
- Weather Forecast Office California Service Area-Products: http://www.cnrfc.noaa.gov/forecasts.php
- El Niño Southern Oscillation (ENSO) Conditions and Weekly Discussion (including La Niña): http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/lanina/enso_evolution-status-fcsts-web.pdf
Sign up for daily email service and you’ll never miss a post!
Sign up for daily emails and get all the Notebook’s aggregated and original water news content delivered to your email box by 9AM. Breaking news alerts, too. Sign me up!
