From the Department of Water Resources:
Forecast Summary:
A Water Year 2019 Water Supply Index (WSI) forecast for conditions as of December 1, 2018 is posted at http://cdec.water.ca.gov/reportapp/javareports?name=WSI. The WSI forecast is based on the precipitation and runoff (full natural flow) through November 2018 and can be summarized as follows:
Sacramento River Unimpaired Runoff Water Year Forecast (50 percent exceedance)
15.2 (85 percent of average)
Sacramento Valley Index (SVI) (50 percent exceedance)
7.0 (Below Normal)
San Joaquin Valley Index (SJI) (75 percent exceedance)
2.4 (Dry)
Runoff:
Unimpaired flows in Percent of Average for Water Year 2019
Oct Runoff
Nov Runoff
Oct-Nov Runoff
Sacramento Valley Index (4 rivers) 78 56 64 San Joaquin Valley Index (6 rivers) 65 56 59 Tulare Lake Basin (4 rivers) 65 55 60
Precipitation:
Precipitation for Water Year 2019 accumulated at the following rates of average
Region WY accumulated precipitation (%) through November 30, 2018 Sacramento River Valley 84 San Joaquin River Valley 125 Tulare Lake Basin 139 Statewide 101 Regional Precipitation Indices As of December 10, 2018 Northern Sierra 8-Station Index 68 (8.5 inches) San Joaquin 5-Station Index 96 (8.6 inches) Tulare Basin 6-Station Index 128 (7.3 inches)
Monthly Precipitation in Percent of Average for Water Year 2019 for Regional Precipitation Indices
Regional Precipitation Indices Oct Nov Northern Sierra 8-Station Index 34 104 San Joaquin 5-Station Index 36 152 Tulare Basin 6-Station Index 125 163
Snowpack:
The snowpack as of the morning of December 10, 2018 stands at the following (based on snow sensors)
Region Snow Water Equivalent (inches) % of Average (Apr 1) % of Average (Dec 10) Northern 4.3 15 69 Central 6.6 22 99 Southern 5.6 22 117 Statewide 5.7 20 94
Weather and Climate Outlooks:
The 6-day weather forecast predicts up to 1.0 inch of precipitation over the Northern Sierra and trace amounts over the Central Sierra. The bulk of the precipitation is expected on Friday with precipitation amounts up to 0.6 inches north of the I-80 corridor. Over the six days, freezing levels will fluctuate between 6,000-9,000 feet over the Northern and Central Sierras and 8,500-11,000 feet over the Southern Sierras.
The NWS Climate Prediction Center (CPC) one‐month outlook for December, valid November 30, indicates increased chances of above normal temperatures for the entire state excluding the southern third of the state where equal chances of above and below normal temperatures are expected. The same outlook suggests increased chances of above normal precipitation for the entire state.
The CPC three‐month (December‐January‐February) outlook, posted November 15, indicates increased chances of above normal temperatures for the entire state with the greatest probabilities in the northern third of the state. The same outlook suggests increased chances of above normal precipitation for the entire state except along the California-Oregon border.
According to the latest El Niño/Southern Oscillation (ENSO) discussion issued by the Climate Prediction Center on December 10, 2018, ENSO-neutral conditions are present. Equatorial sea surface temperatures are above average across most of the Pacific Ocean. El Niño is expected to form and continue through the Northern Hemisphere winter 2018-2019 (~80% chance) and into spring (55-60% chance).
Next Update:
The next WSI forecast for conditions as of January 1, 2019 will be available on January 8, 2019. 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/reportapp/javareports?name=FNF
- Monthly FNF http://cdec.water.ca.gov/reportapp/javareports?name=FNFSUM
- Seasonal FNF http://cdec.water.ca.gov/reportapp/javareports?name=FLOWOUT
Precipitation Data:
- Latest Northern Sierra 8-Station Precipitation Index http://cdec.water.ca.gov/cgi-progs/products/TAB_ESI.pdf
- Latest San Joaquin 5-Station Precipitation Index http://cdec.water.ca.gov/cgi-progs/products/TAB_FSI.pdf
- Latest Tulare Basin 6-Station Precipitation Index http://cdec.water.ca.gov/cgi-progs/products/TAB_TSI.pdf
Snow Data:
- Latest Snow Sensor Report http://cdec.water.ca.gov/reportapp/javareports?name=PAGE6
- Latest Statewide Summary of Snow Water Equivalents http://cdec.water.ca.gov/reportapp/javareports?name=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
Click here to view all posted announcements.
Get the Notebook blog by email and 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!
