Flood Potential Outlook
Issued by NWS Reno, NV

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WATER SUPPLY OUTLOOK
NATIONAL WEATHER SERVICE RENO NV
330 AM PST SAT MAY 10 2014

...WATER SUPPLY OUTLOOK FOR NEVADA AND EASTERN CALIFORNIA AS OF MAY
10 2014...

...WELL BELOW AVERAGE STREAMFLOW IS EXPECTED THIS SPRING AND SUMMER
REGION WIDE...

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

1/SUMMARY...WATER SUPPLY OUTLOOK...AFTER A WETTER THAN NORMAL MARCH
BROUGHT SOME INCREASE TO THE SNOWPACK ACROSS THE REGION...APRIL SAW
BELOW NORMAL PRECIPITATION. THE MIDDLE PORTION OF THE MONTH ALSO
BROUGHT A PERIOD OF WELL ABOVE AVERAGE TEMPERATURES ACROSS EASTERN
CALIFORNIA...WESTERN AND SOUTHERN NEVADA AND ABOVE AVERAGE
TEMPERATURES FOR EASTERN NEVADA. ALL BASINS IN THE EASTERN SIERRA
AND WESTERN NEVADA SAW WELL BELOW AVERAGE APRIL PRECIPITATION WHILE
EASTERN NEVADA FARED SLIGHTLY BETTER...BUT WAS STILL BELOW AVERAGE.
ANY SNOW THAT DID ACCUMULATE DURING THE FIRST HALF OF THE MONTH
BEGAN TO MELT VERY RAPIDLY DURING THE MIDDLE OF THE MONTH.
TEMPERATURES RETURNED TO SLIGHTLY BELOW NORMAL BY THE END OF THE
MONTH AS A LATE MONTH STORM BROUGHT SLIGHT IMPROVEMENT TO THE HIGH
ELEVATION SNOWPACK.

SOIL MOISTURE CONTINUES TO IMPROVE ACROSS THE REGION DUE TO MELTING
SNOW...BUT REMAINS WELL BELOW AVERAGE IN MOST AREAS. EXCEPTIONALLY
DRY SOIL MOISTURE CONDITIONS REMAIN IN THE WALKER BASIN AND EASTERN
NEVADA.

THE WELL BELOW AVERAGE SNOWPACK AND BELOW AVERAGE SOIL MOISTURE WILL
LEAD TO SIGNIFICANTLY REDUCED SPRING RUNOFF. SMALL SNOWPACKS TEND TO
RESULT IN AN EARLIER MELT AND GENERATE LESS STREAMFLOW...LOWER PEAK
FLOWS...MORE INFILTRATION LOSS AND A LONGER IRRIGATION SEASON THAN
SEEN WITH A NORMAL OR ABOVE NORMAL SNOWPACK. AGRICULTURAL INTERESTS
THAT DEPEND ON WATER FROM WINTER SNOWS AND SPRING RUNOFF WILL NEED
TO BE PROACTIVE IN MANAGING WATER RESOURCES THIS YEAR. THE REDUCED
SPRING RUNOFF MAY ALSO LEAD TO EXTREMELY HIGH FIRE DEVELOPING
EARLIER THAN NORMAL THIS SUMMER.

RESERVOIR STORAGE REMAINS LOW AS WELL...SO THERE IS LESS WATER TO
DRAW ON FROM PREVIOUS YEARS. WATER USERS THAT DEPEND ON THIS STORAGE
WILL NEED TO PREPARE FOR POTENTIALLY EXCEPTIONALLY DRY CONDITIONS.

AS OF EARLY MAY...STREAMFLOW FORECASTS ARE EXPECTED TO BE BELOW TO
MUCH BELOW AVERAGE THIS SPRING AND SUMMER.

2/SNOWPACK...
SNOWPACK IN THE EASTERN SIERRA AND WESTERN NEVADA DECREASED ACROSS
ALL BASINS THROUGH APRIL. AS A CONSEQUENCE...MOST BASINS ARE NOW
BELOW TO WELL BELOW AVERAGE. THE ONLY EXCEPTION IS THE CLOVER VALLEY
AND FRANKLIN RIVER BASIN THAT REMAINED JUST ABOVE AVERAGE AS OF MAY
1ST. ACROSS WESTERN NEVADA AND EASTERN CALIFORNIA CONDITIONS REMAIN
WELL BELOW AVERAGE WITH SNOWPACK RANGING FROM 20 TO 50 PERCENT OF
AVERAGE. CONDITIONS ARE SLIGHTLY BETTER IN NORTHERN AND EASTERN
NEVADA AT 43 TO 62 PERCENT OF AVERAGE...EXCEPT FOR THE
AFOREMENTIONED CLOVER VALLEY AND FRANKLIN RIVER BASIN.

                                 MAY 1 2014
BASIN                PERCENT OF MEDIAN
LAKE TAHOE ........................  20
TRUCKEE RIVER .....................  25
CARSON RIVER ......................  34
WALKER RIVER ......................  31
NORTHERN GREAT ....................  NA
UPPER HUMBOLDT RIVER ..............  62
LOWER HUMBOLDT RIVER ..............  50
CLOVER VALLEY & FRANKLIN RIVER .... 107
SNAKE RIVER .......................  61
OWYHEE RIVER ......................  57
EASTERN NEVADA ....................  43
LOWER COLORADO RIVER ..............  NA

3/PRECIPITATION...
PRECIPITATION OVER THE FIRST SEVEN MONTHS OF THE WATER YEAR REMAINS
WELL BELOW AVERAGE FOR MUCH OF NEVADA AND EASTERN CALIFORNIA. WATER
YEAR PRECIPITATION IN THE SIERRA AND WESTERN NEVADA RANGED FROM
AROUND 55 TO 76 PERCENT OF AVERAGE WHILE PRECIPITATION IN EASTERN
AND NORTHEAST NEVADA RANGED FROM 76 TO 89 PERCENT OF AVERAGE. THE
EXCEPTION WAS THE CLOVER VALLEY AND FRANKLIN RIVER BASIN WERE WATER
YEAR PRECIPITATION HAS CLIMBED TO JUST ABOVE AVERAGE.

APRIL PRECIPITATION WAS WELL BELOW AVERAGE FOR MUCH OF EASTERN
CALIFORNIA AND NEVADA. PRECIPITATION WAS NEAR AVERAGE IN THE UPPER
HUMBOLDT AND CLOVER VALLEY AND FRANKLIN RIVER BASINS IN EASTERN
NEVADA AND ABOVE AVERAGE FOR NORTHWEST NEVADA AND EXTREME NORTHEAST
CALIFORNIA.

FOR CONSISTENCY PURPOSES MONTHLY AND WATER YEAR PRECIPITATION TOTALS
ARE BASED ON NRCS MEASUREMENTS.

                                WATER YEAR 2014
                              /THROUGH 5/1/2014/     APRIL 2014
BASIN                         PERCENT OF AVERAGE  PERCENT OF AVERAGE
LAKE TAHOE .........................  66                  63
TRUCKEE RIVER ......................  55                  57
CARSON RIVER .......................  59                  52
WALKER RIVER .......................  56                  60
NORTHERN GREAT .....................  68                 124
UPPER HUMBOLDT RIVER ...............  89                  89
LOWER HUMBOLDT RIVER ...............  76                  56
CLOVER VALLEY AND FRANKLIN RIVER ... 103                  92
SNAKE RIVER ........................  76                  80
OWYHEE RIVER .......................  79                  75
EASTERN NEVADA .....................  76                  75
LOWER COLORADO RIVER ...............  NA                  NA

4/RESERVOIRS...
EARLY MAY RESERVOIR STORAGE IN NORTHERN NEVADA AND EASTERN
CALIFORNIA VARIED FROM A HIGH OF 59 PERCENT OF AVERAGE ON THE
TRUCKEE RIVER BASIN TO A LOW OF 9 PERCENT OF AVERAGE ON THE LOWER
HUMBOLDT RIVER BASIN. RESERVOIR STORAGE INCREASED SLIGHTLY THROUGH
THE MIDDLE OF APRIL DUE TO INCREASED RUNOFF CAUSED BY HIGHER THAN
NORMAL TEMPERATURES...BUT THEN BEGAN TO FALL AGAIN BY THE END OF
MONTH AS IRRIGATION DEMANDS FOR AGRICULTURAL USE BEGAN TO INCREASE
IN THE LOWER PORTIONS OF MOST OF THE BASINS.

BASIN                        PERCENT OF CAPACITY   PERCENT OF AVERAGE
LAKE TAHOE ........................  22 ................  40
TRUCKEE RIVER .....................  40 ................  59
CARSON RIVER ......................  28 ................  41
WALKER RIVER ......................  17 ................  26
LOWER HUMBOLDT RIVER ..............   5 ................   9
OWYHEE RIVER ......................  24 ................  34
LOWER COLORADO RIVER ..............  46 ................  59

5/STREAMFLOW...
APRIL THROUGH JULY STREAMFLOW FORECASTS...EXCEPT AS NOTED BELOW...
FOR NEVADA AND EASTERN CALIFORNIA AS OF MAY 1ST ARE NOTED BELOW. THE
FORECASTS ARE LOWER THAN THE PREVIOUS MONTH FOR ALL BASINS EXCEPT
EASTERN NEVADA DUE TO THE EXTREMELY LOW RUNOFF ALREADY SEEN THIS
YEAR. FORECASTS ARE WELL BELOW AVERAGE FOR WESTERN AND NORTHERN
NEVADA AND THE EASTERN SIERRA...AND BELOW AVERAGE FOR EASTERN
NEVADA. FOR SOUTHERN NEVADA...STREAMFLOWS ON THE VIRGIN RIVER ARE
EXPECTED TO BE WELL BELOW AVERAGE.

                        PERCENT OF AVERAGE APRIL TO JULY STREAMFLOW
                         MOST PROBABLE FORECAST AS OF MAY 1 2014
                            (50 PERCENT CHANCE OF EXCEEDANCE)
BASIN                                     NRCS
LAKE TAHOE RISE .......................... 13
TRUCKEE RIVER .(FARAD).................... 25
CARSON RIVER ..(CARSON CITY).............. 15
WEST WALKER RIVER ........................ 32
EAST WALKER RIVER ..(BRIDGEPORT).......... 10 **
NORTHERN GREAT .....(MCDERMITT)........... 30
UPPER HUMBOLDT RIVER .(PALISADE).......... 16
LOWER HUMBOLDT RIVER .(IMLAY).............  2
CLOVER VALLEY AND FRANKLIN RIVER ......... 57
SNAKE RIVER .............................. 37 @
OWYHEE RIVER .............................  3 @
EASTERN NEVADA .......(AUSTIN)............ 61
LOWER COLORADO RIVER .(LITTLEFIELD)....... 21

** - APRIL TO AUGUST FORECAST
@  - MAY TO JULY FORECAST

                                           APRIL-JULY 50%
                                        EXCEEDANCE FORECAST
                                               (KAF)
FORECAST POINT                                 NRCS
LAKE TAHOE RISE                             0.17 FEET ***
TRUCKEE RIVER AT FARAD                          64
WEST FORK CARSON RIVER AT WOODFORDS             17
EAST FORK CARSON RIVER AT GARDNERVILLE          56
CARSON RIVER AT CARSON CITY                     27
WEST WALKER RIVER BLO LTL WALKER                52
EAST WALKER NEAR BRIDGEPORT                      7 **
HUMBOLDT RIVER NEAR PALISADE                    36
HUMBOLDT RIVER NEAR IMLAY                        4

** - APRIL TO AUGUST FORECAST
*** - LAKE TAHOE RISE GIVEN AS FEET WITH GATES CLOSED

6/ DROUGHT STATUS...
AS OF MAY 6TH 2014...THE UNITED STATES DROUGHT MONITOR CLASSIFIED
PORTIONS OF WEST CENTRAL NEVADA...INCLUDING MUCH OF CHURCHILL AND
PERSHING COUNTIES ALONG WITH WESTERN LANDER COUNTY AS IN EXCEPTIONAL
DROUGHT /LEVEL 4 OF 4 LEVELS OF DROUGHT/. CARSON CITY ALONG WITH ALL
OF DOUGLAS...LYON...STOREY AND WASHOE COUNTIES...THE REMAINDER OF
CHURCHILL...LANDER AND PERSHING COUNTIES...AND PARTS OF
ELKO...EUREKA...HUMBOLDT AND MINERAL AND NYE COUNTIES WERE
CLASSIFIED AS IN EXTREME DROUGHT /LEVEL 3 OF 4 LEVELS OF DROUGHT/.

IN EASTERN CALIFORNIA ALL AREAS WITH THE EXCEPTION OF EXTREME
SOUTHEAST MONO...EASTERN INYO AND ALL BUT FAR WESTERN SAN BERNARDINO
COUNTIES WERE CLASSIFIED IN EXTREME DROUGHT AS WELL.

THE REMAINDER OF NEVADA AND EASTERN CALIFORNIA WAS CLASSIFIED AS
BEING IN SEVERE DROUGHT EXCEPT FOR SMALL PORTIONS OF EASTERN AND
SOUTHERN NEVADA AND EASTERN SAN BERNARDINO COUNTY THAT WERE
CLASSIFIED AS HAVING MODERATE DROUGHT.

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

EXTREMELY HIGH FIRE DANGER THIS COMING SUMMER...AS TEMPERATURES WARM
AND FUELS DRY.

POSSIBLE WATER SUPPLY DEFICITS...RESERVOIR STORAGE REMAINS LOW AND
WATER SUPPLY COULD BECOME AN ISSUE THROUGHOUT THE REGION THIS COMING
SPRING AND SUMMER. WATER SUPPLY CONCERNS WOULD BE HIGHEST ON BASINS
WITHOUT RESERVOIR STORAGE.

7/ LONG RANGE WEATHER OUTLOOK FOR NEVADA AND EASTERN CALIFORNIA...
THE OUTLOOK FOR THE REMAINDER OF MAY...IS FOR EQUAL CHANCES OF
BELOW...ABOVE AND NEAR NORMAL PRECIPITATION FOR ALL OF EASTERN
CALIFORNIA AND NEVADA. TEMPERATURES ARE EXPECTED TO BE ABOVE AVERAGE
FOR ALL OF EASTERN CALIFORNIA ALONG WITH WESTERN AND SOUTHERN
NEVADA. FOR NORTH CENTRAL...NORTHEAST AND EASTERN NEVADA...THERE ARE
EQUAL CHANCES FOR BELOW...ABOVE AND NEAR NORMAL TEMPERATURES.

THE LONG RANGE OUTLOOK FOR THE MONTHS OF JUNE THROUGH AUGUST IS FOR
ABOVE NORMAL TEMPERATURES FOR ALL OF NEVADA AND EASTERN CALIFORNIA.
THERE IS AN EQUAL CHANCE OF ABOVE...NEAR AND BELOW NORMAL
PRECIPITATION FOR ALL OF EASTERN CALIFORNIA AND NEVADA.

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...
HTTP://WWW.CNRFC.NOAA.GOV/WATER_SUPPLY.PHP

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

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

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

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

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