Extended Streamflow Guidance
Issued by NWS

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SPRING FLOOD POTENTIAL OUTLOOK
NATIONAL WEATHER SERVICE
CALIFORNIA-NEVADA RIVER FORECAST CENTER SACRAMENTO CA
1200 PM PST THU MAR 5 2015

...BELOW AVERAGE FLOOD POTENTIAL EXPECTED FOR CALIFORNIA THIS
SPRING...

THE SPRING FLOOD POTENTIAL OUTLOOK IS BELOW AVERAGE FOR ALL BASINS
IN CALIFORNIA AND THE UPPER KLAMATH LAKE BASIN IN OREGON.  LOW
SOIL MOISTURE CONDITIONS DUE TO PROLONGED DROUGHT AND/OR BELOW
NORMAL SNOWPACKS ARE MINIMIZING THE POTENTIAL FOR FLOODING.  IT
APPEARS THAT CALIFORNIA WILL HAVE TO ENDURE ITS FOURTH
CONSECUTIVE YEAR OF BELOW AVERAGE SPRING RUNOFF.

THE APRIL 1ST AVERAGE SNOWPACK IS MUCH WORSE THAN AT THIS TIME
LAST YEAR.  VIRTUALLY THE ENTIRE STATE BENEFITED FROM EXCELLENT
DECEMBER PRECIPITATION. HOWEVER, JANUARY TURNED OUT TO BE VERY DRY.
SOME RELIEF OCCURRED DURING FEBRUARY AND THE BEGINNING OF MARCH
PREDOMINANTLY OVER THE NORTH HALF OF THE STATE.  MUCH OF THE
PRECIPITATION THAT FELL DURING DECEMBER AND FEBRUARY WAS WARM IN
NATURE, INCREASING STORAGE TO MANY RESERVOIRS BUT ADDING LITTLE
TO THE MOUNTAIN SNOW PACK.  IT WILL TAKE A SERIES OF STRONG, COLD
STORM SYSTEMS TO RETURN THE SNOWPACK TO NORMAL CONDITIONS BY
APRIL 1ST...WHICH IS THE TYPICAL TIME OF MAXIMUM SNOWPACK
ACCUMULATION.  IT APPEARS VERY UNLIKELY THAT SNOWPACKS CAN RECOVER
FROM THE CURRENT DEFICIT THIS LATE INTO THE WET SEASON. NOTE THAT
FLOODING COULD STILL RESULT FROM HEAVY RAINFALL ALONE OR
COMBINED WITH SNOWMELT ANYTIME BETWEEN NOW AND EARLY APRIL.

PRECIPITATION...
NEAR TO ABOVE AVERAGE PRECIPITATION FELL ON MUCH OF THE REGION
DURING FEBRUARY 2015.  HOWEVER...THE WATER YEAR AVERAGE IS
VERY LOW FOR WATERSHEDS IN THE SOUTHERN SIERRA NEVADA, PORTIONS
OF THE CENTRAL COAST AND THE SOUTH COAST.

                   PERCENT OF AVG PCPN         PERCENT OF AVG PCPN
BASIN                 FEBRUARY 2015               WATER YEAR 2015
UPPER KLAMATH              108                           99
LOWER KLAMATH              159                           98
TRINITY                     82                           62
EEL RIVER                  123                           93
RUSSIAN                     69                           86
NAPA                        67                           90
SF BAY AREA                118                           95
UPPER SACRAMENTO           129                          102
FEATHER                     95                           79
YUBA                        79                           77
AMERICAN                    79                           73
MOKELUMNE                  102                           81
STANISLAUS                  82                           59
TUOLUMNE                    72                           57
MERCED                      65                           45
UPPER SAN JOAQUIN           53                           56
KINGS                       76                           56
KAWEAH                      67                           58
KERN                        52                           53
CENTRAL COAST
    SANTA CRUZ              46                           81
    PAJARO RIVER            46                           93
    SALINAS RIVER           62                           91
    SAN LUIS OBISPO         45                           58
    SANTA YNEZ              11                           48
SOUTH COAST
    SANTA BARBARA COAST     23                           67
    VENTURA LA COASTAL      24                           69
    SANTA CLARA RIVER       18                           73
    LOS ANGELES RIVER       22                           60
    SANTA ANA RIVER         20                           61
    SAN DIEGO BASIN         18                           64

SOUTH EAST DESERTS
    OWENS RIVER             20                           33
    AMARGOSA                51                           88
    MOJAVE DESERT           18                           67
    MOJAVE RIVER            70                          114
    COLORADO RIVER          21                           54
    WHITEWATER RIVER        15                           35

SNOWPACK...
SNOW MEASUREMENTS TAKEN FROM SNOW COURSES CONFIRM THAT
CALIFORNIA`S MOUNTAIN SNOWPACK NOT ONLY HOLDS FAR LESS WATER THAN
NORMAL BUT IS MORE DISMAL THAN IT WAS AT THIS TIME LAST
YEAR.  CURRENTLY, IT IS AMONG THE LOWEST ON RECORD, RIVALING
THE LOW PACK YEARS OF 1977 AND 1991.

               PERCENT OF AVG SNOWPACK    PERCENT OF AVG SNOWPACK
BASIN                 MARCH 1 2014             MARCH 1 2015
NORTH COAST                13                        13
SACRAMENTO                 15                         8
SAN JOAQUIN VALLEY         29                        15
TULARE LAKE                24                        18
UPPER KLAMATH*             31                        17

  * PERCENT MEDIAN AS REPORTED BY THE NRCS, PORTLAND

RESERVOIRS... UNLIKE LAST YEAR ON FEBRUARY 28...STORAGE IN MANY OF
CALIFORNIA`S MAJOR RESERVOIRS STAND AT MUCH BELOW AVERAGE...

               PERCENT OF AVG STORAGE
RESERVOIR             FEB 28 2015
SHASTA LAKE                 73
LAKE OROVILLE               73
YUBA-BULLARDS BAR           90
AMERICAN-FOLSOM LAKE       110
STANISLAUS-NEW MELONES      43
TUOLUMNE                    58
MERCED-LAKE MCCLURE         17
SAN JOAQUIN-MILLERTON LAKE  59
KINGS-PINE FLAT             33
KERN-ISABELLA               25
UPPER KLAMATH LAKE, OR     112


RUNOFF...
THE PREDOMINANTLY DRY CONDITIONS SO FAR THIS WATER YEAR ARE
REFLECTED IN THE BELOW AVERAGE RUNOFF CONDITIONS FOR
FEBRUARY 28.  THIS IS PARTICULARLY EVIDENT IN THE SAN JOAQUIN
AND TULARE LAKE REGION OF THE SIERRA NEVADA...

                 PERCENT OF AVG RUNOFF    PERCENT OF AVG RUNOFF
BASIN                 FEBRUARY 2015      OCT 1 2014-FEB 28 2015
TRINITY-SACRAMENTO          83                      80
SAN JOAQUIN                 62                      40
TULARE LAKE                 42                      32
UPPER KLAMATH               86                      85

STREAMFLOW FORECASTS...
APRIL THROUGH JULY FORECASTS DERIVED FROM ENSEMBLE GUIDANCE ARE
GENERALLY MUCH BELOW AVERAGE FOR UPPER SACRAMENTO/WEST-SLOPE
SIERRA NEVADA WATERSHEDS AT THE 50 PERCENT EXCEEDENCE LEVEL.
THE APRIL THROUGH SEPTEMBER FORECAST FOR UPPER KLAMATH LAKE
IS ABOUT 71 PERCENT OF AVERAGE.


TO SUMMARIZE... THE FLOOD POTENTIAL IS BELOW AVERAGE FOR ALL
WATERSHEDS IN CALIFORNIA TYPICALLY AFFECTED BY SPRINGTIME
SNOWMELT...AS WELL AS OTHER REGIONS IN THE STATE WHERE SNOWMELT
IS NOT A MAJOR FACTOR IN SPRINGTIME FLOODING.  THIS IS SUPPORTED
BY LOW SOIL MOISTURE CONTENT IN MANY AREAS DUE TO PROLONGED DRY
PERIODS DURING THE PAST YEAR...MUCH BELOW AVERAGE MOUNTAIN
SNOWPACKS...AMPLE ROOM FOR STORAGE IN MANY OF THE STATE`S LARGE
RESERVOIRS...AND MUCH BELOW AVERAGE SPRING RUNOFF FORECASTS AT THE
PRESENT TIME.

CNRFC/AT



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