Weather Service Report


698 
AXUS76 KSTO 250528
DGTSTO
CAC003-005-007-009-011-017-021-035-057-061-063-067-077-089-091-
095-099-101-103-109-113-115-210530-

Drought Information Statement
National Weather Service Sacramento CA
1027 PM PDT Tue Aug 24 2021

...EXCEPTIONAL DROUGHT CONDITIONS ACROSS MOST OF NORTHERN 
CALIFORNIA...

SYNOPSIS...

According to the U.S. drought monitor, much of inland California 
is in D4 exceptional drought. The exception is the high Sierra
which is in D3 severe drought conditions. The drought classifications
are due to the short term precipitation deficit of the 2020 and 
2021 dry water years.

https://droughtmonitor.unl.edu/currentmap/statedroughtmonitor.as
px?ca

The drought emergency declared by Governor Newsom across 50 
counties in California on May 10, 2021, remains unchanged. The 
emergency proclamation was issued in response to below normal 
precipitation this year and a second consecutive year of dry 
conditions. The declaration was expanded due to the warm spring 
temperatures that led to a rapid depletion of the Sierra Nevada 
snowpack, low streamflow, less inflow into reservoirs, and hence a
rapid deterioration of the state's water supply. D4-Exceptional 
Drought classification indicates exceptional and widespread 
crop/pasture losses and shortages of water in reservoirs, streams,
and wells creating water emergencies. The declaration paves the 
way to expeditiously mitigate the effects of drought conditions to
ensure the protection of health, safety, and the environment. 

SUMMARY OF IMPACTS... 

Agriculture, livestock and rangeland damages and losses caused by 
the dry conditions. Abnormally dry vegetation is contributing to 
a record 2020 and 2021 fire season with several large, devastating
fires ongoing. Numerous hydrologic power stations are running at 
a degraded state or are unable to generate power due to the lack 
of water storage in reservoirs. Water storages at many of the 
large reservior are below the lowest levels during the 2011-2016 
drought.

CLIMATE SUMMARY...

The 2020 and 2021 water years have been extremely dry over northern 
California, ranking among the top two driest for a 2 year period 
at many locations. The summer of 2020 was the hottest on record 
for many locations in norcal. 

The northern sierra 8 station precipitation index for the 2020 water 
year finished at 31.9 inches or 62% of normal, which was the 3rd 
driest on record. The 5 station San Joaquin basin index finished at 
24.6 inches or 61% of normal, which was the 7th driest on record.

PRECIPITATION/TEMPERATURE OUTLOOK...                          

The wet season has ended and it has been extremely dry. The peak 
of the dry season is ongoing over northern California. The 
current station 8 index for the northern Sierra is at 46 percent 
of normal and the central Sierra station 5 index is at 47 percent 
of normal. 

CPC 3-month outlook through February, shows a slight signal for
below normal precipitation south of Interstate 80 and no clear
signal to the north. Trends point to above-normal temperatures 
across the entire state. 

The La Nia Watch issued by the Climate Prediction Center on July 8, 
2021 remains in effect.  A Watch is issued when conditions are 
favorable for the development of El Nio or La Nia conditions 
within the next six months. ENSO-neutral conditions are currently in 
place across the Pacific. There is a 60% chance that ENSO-neutral 
conditions will continue through the remainder of the summer season 
(Aug-Sept 2021) with La Nia conditions emerging during the fall 
season (Aug-Sept-Oct 2021) and a 70% chance of La Nia conditions 
lasting through the 2021-22 winter season (Nov-Dec-Jan).  A second 
year La Nia event is possible, and the models have been fairly 
consistent in La Nia emerging in the fall.

HYDROLOGIC SUMMARY AND OUTLOOK... 
A second extremely dry water year has caused a reduction in the 
water storage of the state's large reservoirs, now ranging from 35 
to 70 percent of normal. Reservoir storage for the Sacramento 
river basin is at 55% of average. 

NEXT ISSUANCE DATE... The next scheduled product will be issued in 
late September or sooner if necessary in response to significant 
changes in conditions.

&&

RELATED WEBSITES... 
California Data Exchange Center: 
http://cdec.water.ca.gov/ 

California Nevada River Forecast Center: 
http://www.cnrfc.noaa.gov/droughtInfo.php 

U.S. Drought Monitor: 
https://droughtmonitor.unl.edu/CurrentMap/StateDroughtMonitor.
aspx?CA 

National Integrated Drought Information System: 
https://www.drought.gov/states/california 

California Department of Water Resources Drought Page: 
https://water.ca.gov/Water-Basics/Drought 

Climate Prediction Center: 
https://www.cpc.ncep.noaa.gov/ 
https://www.cpc.ncep.noaa.gov/products/monitoring_and_data/ 
drought.shtml 

National Center for Environmental Information: 
https://www.ncdc.noaa.gov/sotc/drought/ 

National Weather Service Sacramento: http://www.wrh.noaa.gov/sto/ 

National Weather Service California drought information resources: 
https://www.weather.gov/safety/drought-ww Association of California 

Water Agencies:  http://www.acwa.com

ACKNOWLEDGMENTS...
CLIMATE PREDICTION CENTER
DROUGHT MONITOR
CALIFORNIA NEVADA RIVER FORECAST CENTER
NATIONAL WEATHER SERVICE SACRAMENTO
CALIFORNIA DEPARTMENT OF WATER RESOURCES
CALIFORNIA STATE CLIMATOLOGIST
US BUREAU OF RECLAMATION
CAL FIRE
ASSOCIATION OF CALIFORNIA WATER AGENCIES
LOCAL COUNTIES AND CITIES

QUESTIONS AND COMMENTS...PLEASE REFER ALL QUESTIONS TO 
W-STO.WEBMASTER@NOAA.GOV.

$$

SHOEMAKER

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Western Regional Climate Center, wrcc@dri.edu