National Weather Service Text Product Display

Flood Potential Outlook
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WATER SUPPLY OUTLOOK
NATIONAL WEATHER SERVICE RENO NV
230 PM PDT THU MAY 9 2013

...WATER SUPPLY OUTLOOK FOR NEVADA AND EASTERN CALIFORNIA AS OF MAY
9 2013...

...NEVADA AND EASTERN CALIFORNIA WILL EXPERIENCE A SECOND DRY SPRING
AND SUMMER IN A ROW...WITH MUCH BELOW NORMAL STREAMFLOW EXPECTED...

...ISSUED JOINTLY BY THE NATIONAL WEATHER SERVICE AND NATURAL
RESOURCES CONSERVATION SERVICE...

1/SUMMARY...WATER SUPPLY OUTLOOK...
AS OF EARLY MAY...ONLY HIGH ELEVATION SNOW REMAINS TO PROVIDE WHAT
WILL BE A VERY LIMITED RUNOFF SEASON. THE HIGHEST FLOWS OF THE
SPRING SNOWMELT SEASON ARE EXPECTED ON EASTERN SIERRA AND WESTERN
NEVADA RIVERS AND STREAMS BY MID MAY AS THE WEATHER WARMS. THE
HUMBOLDT RIVER IS EXPECTED TO CREST BY EARLY JUNE.

HOWEVER...FLOWS ON ALL RIVERS AND STREAMS WILL BE FAR BELOW NORMAL
THIS SPRING AND SUMMER. IT WILL BE A REPEAT OF LAST YEAR...BUT
WITHOUT THE AMPLE RESERVOIR STORAGE MOST BASINS HAD GOING INTO LAST
SUMMER. WATER SUPPLY NEEDS WILL BECOME AN ISSUE FOR THOSE AREAS WITH
INADEQUATE OR NO RESERVOIR STORAGE.

COOL TEMPERATURES AND PRECIPITATION OVER MOST OF THE REGION MAY 5TH
TO 8TH PROVIDED SOME MINIMAL TEMPORARY RELIEF FROM THE ONGOING
DROUGHT AS EVAPORATION AND WATER USE WAS REDUCED. HOWEVER...AS THE
WEATHER WARMS AND DRIES...IMPACTS FROM DRY CONDITIONS WILL AGAIN BE
APPARENT. LOW STREAMFLOWS AND WATER STRESSED VEGETATION ARE JUST A
FEW OF THE EARLY SEASON INDICATORS OF A DRY WINTER. FIRE DANGER WILL
INCREASE...ESPECIALLY IN TIMBERED AREAS. EARLY MAY PRECIPITATION
THROUGHOUT MUCH OF THE REGION WILL CAUSE RANGE GRASSES TO GREEN UP
IN MANY AREAS...INCREASING FIRE DANGER ON RANGELANDS.  NATURAL WATER
SOURCES SUCH AS SPRINGS AND CREEKS WILL DRY UP THIS SUMMER...FURTHER
IMPACTING VEGETATION...WILDLIFE AND RANCHING.

ON A BRIGHTER NOTE...RESERVOIR STORAGE IS CURRENTLY ADEQUATE FOR THE
MOST POPULATED AREAS OF NEVADA AND EASTERN CALIFORNIA...AND ONLY
NORMAL WATERING RESTRICTIONS ARE IN PLACE.

2/SNOWPACK...
EARLY MAY SNOWPACK CONDITIONS IN NEVADA AND EASTERN CALIFORNIA WERE
EXTREMELY LOW.  AS OF MAY 9...THE SNAKE RIVER BASIN HAD THE HIGHEST
VALUE AT 70 PERCENT OF MEDIAN...WHILE THE CLOVER VALLEY AND FRANKLIN
RIVER BASIN REPORTED NO SNOW AT ITS SNOW DATA SITES.

                                  MAY 9 2012           MAY 9 2013
BASIN                         PERCENT OF MEDIAN     PERCENT OF MEDIAN
LAKE TAHOE .........................  22 ................   4
TRUCKEE RIVER ......................  48 ................  37
CARSON RIVER .......................  22 ................  23
WALKER RIVER .......................  24 ................  45
NORTHERN GREAT .....................  55 ................  53
UPPER HUMBOLDT RIVER ...............   0 ................  17
LOWER HUMBOLDT RIVER ...............   0 ................  41
CLOVER VALLEY & FRANKLIN RIVER .....   0 ................   0
SNAKE RIVER ........................   3 ................  70
OWYHEE RIVER .......................   0 ................  16
EASTERN NEVADA .....................   5 ................  45

3/PRECIPITATION...
APRIL PRECIPITATION FAILED TO PROVIDE MUCH RELIEF AS AMOUNTS WERE
GENERALLY HALF TO TWO THIRDS OF AVERAGE. WATER YEAR PRECIPITATION
CONTINUED TO LAG WELL BELOW AVERAGE...WITH THE LONE EXCEPTION OF THE
SNAKE RIVER BASIN WHICH WAS JUST SLIGHTLY BELOW AVERAGE. WHILE
SEVERAL STORMS DID IMPACT THE REGION IN APRIL...NONE PRODUCED ENOUGH
PRECIPITATION TO BEGIN TO OVERCOME THE DEFICITS. APRIL PRECIPITATION
WAS HIGHEST ON THE SNAKE RIVER BASIN AT 88 PERCENT OF AVERAGE AND
LOWEST ON THE TRUCKEE RIVER BASIN AT 36 PERCENT OF AVERAGE. WATER
YEAR PRECIPITATION AS OF MAY 1 WAS HIGHEST ON THE SNAKE RIVER BASIN
AT 91 PERCENT OF AVERAGE AND LOWEST ON THE LOWER COLORADO RIVER
BASIN AT 50 PERCENT OF AVERAGE.
                                    APRIL           WATER YEAR 2013
BASIN                         PERCENT OF AVERAGE   PERCENT OF AVERAGE
LAKE TAHOE ........................  64 ................  82
TRUCKEE RIVER .....................  36 ................  73
CARSON RIVER ......................  45 ................  73
WALKER RIVER ......................  60 ................  75
NORTHERN GREAT ....................  60 ................  74
UPPER HUMBOLDT RIVER ..............  64 ................  78
LOWER HUMBOLDT RIVER ..............  42 ................  76
CLOVER VALLEY AND FRANKLIN RIVER ..  75 ................  66
SNAKE RIVER .......................  88 ................  91
OWYHEE RIVER ......................  58 ................  79
EASTERN NEVADA ....................  79 ................  78
LOWER COLORADO RIVER ..............  41 ................  50

4/RESERVOIRS...
RESERVOIR STORAGE IN NEVADA AND EASTERN CALIFORNIA CONTINUED TO
DECLINE IN MOST BASINS. AS OF EARLY MAY...RESERVOIR STORAGE WAS
HIGHEST ON THE TRUCKEE RIVER BASIN AT 101 PERCENT OF AVERAGE. THE
LOWER HUMBOLDT RIVER BASIN WAS LOWEST AT 23 PERCENT OF AVERAGE.

BASIN                        PERCENT OF CAPACITY   PERCENT OF AVERAGE
LAKE TAHOE ........................  50 ................  93
TRUCKEE RIVER .....................  68 ................ 101
CARSON RIVER ......................  41 ................  59
WALKER RIVER ......................  32 ................  48
LOWER HUMBOLDT RIVER ..............  12 ................  23
OWYHEE RIVER ......................  45 ................  65
LOWER COLORADO RIVER ..............  52 ................  62

5/STREAMFLOW...
APRIL TO JULY STREAMFLOW FOR NEVADA AND EASTERN CALIFORNIA IS
FORECAST TO BE WELL BELOW AVERAGE. STREAMFLOW IS EXPECTED TO BE
HIGHEST IN THE SNAKE RIVER BASIN AT 63 PERCENT OF AVERAGE...WHILE
THE OWYHEE RIVER BASIN IS EXPECTED TO BE LOWEST AT 5 PERCENT OF
AVERAGE.

                     PERCENT OF AVERAGE APRIL TO JULY STREAMFLOW
                 MOST PROBABLE FORECAST FROM NRCS AS OF MAY 1 2013
BASIN                    /50 PERCENT CHANCE OF EXCEEDANCE/
LAKE TAHOE ..........................  31
TRUCKEE RIVER .......................  38
CARSON RIVER ........................  30
WALKER RIVER ........................  54
NORTHERN GREAT ......................  45
UPPER HUMBOLDT RIVER ................  25
LOWER HUMBOLDT RIVER ................  10
CLOVER VALLEY AND FRANKLIN RIVER ....  45
SNAKE RIVER .........................  63
OWYHEE RIVER ........................   5
EASTERN NEVADA ......................  25
LOWER COLORADO RIVER ................  41

/NOTE...NWS ALSO FORECASTS WATER SUPPLY FOR MANY OF THESE BASINS.
NWS FORECAST VALUES MAY DIFFER SLIGHTLY FROM NRCS FORECASTS./

6/ DROUGHT STATUS...
AS OF MAY 8 2013...ALL COUNTIES IN NEVADA AND ALL CALIFORNIA
COUNTIES ALONG THE NEVADA BORDER REMAINED DESIGNATED NATURAL DROUGHT
DISASTER AREAS...EITHER AS PRIMARY COUNTIES OR CONTIGUOUS
COUNTIES...BY THE U.S. DEPARTMENT OF AGRICULTURE.

PRIMARY DROUGHT DISASTER COUNTIES IN CALIFORNIA ALONG THE NEVADA
BORDER INCLUDED MODOC...LASSEN...MONO...INYO AND SAN BERNARDINO.

ALL NEVADA COUNTIES HAD BEEN DECLARED PRIMARY DROUGHT DISASTER
COUNTIES WITH THE EXCEPTION OF EUREKA COUNTY.

AS OF MAY 7 2013...THE UNITED STATES DROUGHT MONITOR CLASSIFIED
PORTIONS OF WEST CENTRAL AND NORTHEASTERN NEVADA AS IN EXTREME
DROUGHT /LEVEL 3 OF 4 LEVELS OF DROUGHT/. THIS AREA INCLUDED MUCH OF
PERSHING...ALL OF CHURCHILL...EASTERN LYON AND EXTREME NORTHERN
MINERAL COUNTIES...AS WELL AS SOUTHEAST ELKO COUNTY.  ALL OF THE
REST OF NEVADA WAS IN MODERATE TO SEVERE DROUGHT /LEVELS 1 AND
2/...WITH THE EXCEPTION OF NORTHEAST CLARK...SOUTHEAST LINCOLN AND
NORTHERN ELKO COUNTIES...WHICH WERE CLASSIFIED AS ABNORMALLY DRY. IN
CALIFORNIA...MONO...INYO AND SAN BERNARDINO COUNTIES WERE IN SEVERE
DROUGHT...WHILE ALPINE COUNTY NORTH TO MODOC COUNTY WERE IN MODERATE
DROUGHT.

7/ DROUGHT IMPACTS...
POSSIBLE IMPACTS FROM DROUGHT IN NEVADA AND EASTERN CALIFORNIA
INCLUDE...

A/ HIGH FIRE DANGER...
AS TEMPERATURES WARM AND FUELS DRY...FIRE DANGER WILL INCREASE
THROUGHOUT THE REGION. FIRE DANGER WILL BE ESPECIALLY HIGH THIS
SUMMER IN TIMBERED AREAS OF THE SIERRA AND SOUTHERN CASCADES IN
CALIFORNIA AND WEST CENTRAL NEVADA...AND ALSO IN ELKO COUNTY
NEVADA...WHERE FUELS HAVE BEEN DRIER THAN NORMAL FOR TWO CONSECUTIVE
YEARS.  EARLY MAY PRECIPITATION THROUGHOUT MUCH OF THE REGION WILL
CAUSE RANGE GRASSES TO GREEN UP IN MANY AREAS...INCREASING FIRE
DANGER ON RANGELANDS.

AS OF MAY 8...NEVADA AND EASTERN CALIFORNIA WERE REPORTING LOW TO
MODERATE FIRE DANGER DUE TO RECENT PRECIPITATION. HOWEVER...FIRE
DANGER WILL INCREASE AS TEMPERATURES RISE AND FUELS DRY.

B/ AGRICULTURE...
AREAS WHICH RELY ON IRRIGATED AGRICULTURE FOR A SIGNIFICANT PORTION
OF THEIR ECONOMY ARE ESPECIALLY VULNERABLE TO WATER SUPPLY SHORTAGES
THIS YEAR. WATER SUPPLY CONCERNS ARE HIGHEST ON BASINS WITH NO OR
INADEQUATE RESERVOIR STORAGE...SUCH AS THE HUMBOLDT BASIN...WALKER
BASIN...AND CARSON RIVER BASIN ABOVE LAHONTAN RESERVOIR. AREAS THAT
GET WATER DIRECTLY FROM A RIVER OR CREEK THAT DOES NOT HAVE STORAGE
CAN EXPECT FLOWS TO DECLINE EARLIER THAN NORMAL THIS YEAR.

C/ RANCHING...
RANCHERS WILL EXPERIENCE IMPACTS AS THEY MAY NEED TO HAUL FEED AND
WATER TO LIVESTOCK AS THEY MAY NOT BE AVAILABLE FROM NATURAL
SOURCES.

D/ FISHERIES...
LOW FLOWS AND HIGH WATER TEMPERATURES IN RIVERS AND STREAMS WILL
LIKELY CAUSE SIGNIFICANT IMPACTS TO FISH AND OTHER AQUATIC SPECIES.

E/ VEGETATION AND WILDLIFE...
IN FORESTED AREAS...DROUGHT MAY CAUSE TREES TO BECOME SUSCEPTIBLE TO
INSECT INFESTATIONS WHICH COULD INCREASE MORTALITY AND FIRE DANGER.
LESS VEGETATION AND WATER MAY STRESS WILDLIFE REGION WIDE...CAUSING
DEHYDRATION...HUNGER...ILLNESS AND DEATH AS A RESULT.

F/ GROUND WATER...
HIGH EMPHASIS WILL BE PLACED ON GROUND WATER SUPPLIES IN SOME AREAS
AS SURFACE WATER DWINDLES THIS SUMMER. INCREASED GROUND WATER
PUMPING MAY CAUSE WATER TABLES TO DECLINE...WITH THE POSSIBILITY
THAT SOME WELLS MAY GO DRY OR WILL NEED TO BE DEEPENED.

G/ URBAN AREA DROUGHT IMPACTS...
THANKFULLY...NO SIGNIFICANT WATER SUPPLY SHORTAGES ARE EXPECTED AT
THIS TIME IN ANY OF THE MAJOR POPULATION CENTERS IN NEVADA OR
EASTERN CALIFORNIA.

8/ LONG RANGE WEATHER OUTLOOK FOR NEVADA AND EASTERN CALIFORNIA...

THE OUTLOOK FOR THE REST OF MAY...IS FOR ABOVE NORMAL TEMPERATURES
THROUGHOUT THE REGION. PRECIPITATION IS EXPECTED TO BE SOMEWHAT
BELOW NORMAL IN NORTHERN NEVADA AND NORTHEAST CALIFORNIA...WHILE THE
REST OF THE REGION CAN EXPECT NEAR NORMAL PRECIPITATION.

THE OUTLOOK FOR THE MONTHS OF MAY THROUGH JULY IS FOR ABOVE NORMAL
TEMPERATURES THROUGHOUT MOST OF THE REGION...ESPECIALLY IN EASTERN
NEVADA. TEMPERATURES IN NORTHWEST NEVADA AND NORTHERN AND CENTRAL
CALIFORNIA ARE EXPECTED TO BE NEAR NORMAL. PRECIPITATION IS EXPECTED
TO BE BELOW NORMAL IN NORTHEAST CALIFORNIA AND NORTHERN AND CENTRAL
NEVADA.  THERE ARE EQUAL CHANCES OF HAVING ABOVE NORMAL...NEAR
NORMAL OR BELOW NORMAL PRECIPITATION THROUGHOUT THE REST OF THE
REGION.

9/ FOR MORE DETAILED WATER SUPPLY AND STREAMFLOW FORECAST
INFORMATION FOR NEVADA AND EASTERN CALIFORNIA...PLEASE REFER TO THE
FOLLOWING WEB SITES /NOTE...ALL LETTERS IN WEB SITE ADDRESSES ARE
LOWER CASE/...

NWS CALIFORNIA NEVADA RIVER FORECAST CENTER...
WWW.CNRFC.NOAA.GOV/WATER_SUPPLY.PHP

NWS NORTHWEST RIVER FORECAST CENTER...
WWW.NWRFC.NOAA.GOV/WS/

NWS COLORADO BASIN RIVER FORECAST CENTER...
WWW.CBRFC.NOAA.GOV/

NEVADA NATURAL RESOURCES CONSERVATION SERVICE...
WWW.NV.NRCS.USDA.GOV/SNOW/

CALIFORNIA DEPT. OF WATER RESOURCES...
CDEC.WATER.CA.GOV/

NWS CLIMATE PREDICTION CENTER LONG RANGE OUTLOOK MAPS...
WWW.CPC.NCEP.NOAA.GOV/PRODUCTS/FORECASTS/

U.S. DROUGHT PORTAL...INCLUDING U.S. DROUGHT MONITOR...
DROUGHT.GOV/DROUGHT

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National Weather Service Weather Forecast Office
