2012 Water Supply and Spring Snowmelt Flood Outlook

PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE CHEYENNE WY
708 AM MST THU JAN 26 2012

...SPRING 2012 FLOOD AND WATER RESOURCES OUTLOOK NUMBER ONE...

THIS FLOOD OUTLOOK ENCOMPASSES THE NORTH PLATTE RIVER MAINSTEM AND
ITS TRIBUTARIES...THE LARAMIE AND MEDICINE BOW RIVERS...IN SOUTHEAST
WYOMING AND THE NEBRASKA PANHANDLE. LIKEWISE...IT ALSO INCLUDES THE
TRIBUTARIES TO THE MISSOURI RIVER...NIOBRARA AND WHITE RIVERS...IN
EXTREME NORTHWESTERN NEBRASKA.  FINALLY...IT ALSO INCLUDES THE LITTLE
SNAKE RIVER DRAINAGE OF SOUTH CENTRAL WYOMING.

...MODERATE SNOWMELT FLOOD POTENTIAL IS EXPECTED ALONG THE LITTLE SNAKE
RIVER AND SAVERY CREEK...
...LOW SPRING SNOWMELT FLOOD POTENTIAL IS EXPECTED FOR THE UPPER NORTH
PLATTE RIVER...LARAMIE RIVER...LITTLE LARAMIE RIVER...ENCAMPMENT RIVER
AND MEDICINE BOW RIVER...

...ABNORMALLY DRY CONDITIONS EXIST AT MID JANUARY FOR SOUTHERN CARBON
COUNTY...WITH MODERATE DROUGH CONDITIONS OVER FAR SOUTHWEST CARBON
COUNTY. NO DROUGHT CONDITIONS CURRENTLY EXIST OVER THE REMAINDER OF
SOUTHEAST WYOMING AND THE WESTERN NEBRASKA PANHANDLE.  THOSE CONDITIONS
ARE EXPECTED TO CONTINUE UNCHANGED THROUGH APRIL...

THIS OUTLOOK IS VALID THROUGH THE END OF JUNE.  THE NEXT SPRING 2011
PROBABILISTIC HYDROLOGY OUTLOOK WILL BE ISSUED IN MID FEBRUARY.

     ...CURRENT HYDROLOGIC CONDITIONS...

MANY OF THE SMALLER STREAMS IN THE REGION NEAR THE MOUNTAINS WERE
EITHER FROZEN OR STREAM FLOW WAS BELOW AVERAGE AT THE END OF JANUARY.

FALL 2011...SEPTEMBER THROUGH NOVEMBER...TEMPERATURES WERE WELL ABOVE
NORMAL IN SOUTHEAST WYOMING AND THE WESTERN NEBRASKA PANHANDLE.  THE
TEMPERATURES WERE BETWEEN 4 AND 6 DEGREES ABOVE AVERAGE FOR THAT TIME
PERIOD.  DECEMBER 2011 WAS COOLER OVER SOUTHEAST WYOMING...WITH
READINGS BELOW NORMAL.  MEANWHILE...ABOVE NORMAL TEMPERATURES CONTINUED
FOR THE WESTERN NEBRASKA PANHANDLE.

PRECIPITATION WAS BETWEEN 75 AND 100 PERCENT OF NORMAL VALUES FOR FALL
2011...SEPTEMBER THROUGH NOVEMBER.  MOST OF THE AREA WAS EVEN DRIER IN
DECEMBER 2011...WITH BETWEEN 50 AND 75 PERCENT OF NORMAL VALUES

THE RESULTING SNOWPACK FROM SNOTEL SITES AS OF JANUARY 1 2012 WAS BELOW
NORMAL OVER SOUTHEAST WYOMING AND THE WESTERN NEBRASKA PANHANDLE.  AS
OF JANUARY 25 2012...BASIN SNOW WATER EQUIVALENT VALUES RANGED FROM 81
PERCENT IN THE LOWER NORTH PLATTE BASIN TO 59 PERCENT IN THE LITTLE
SNAKE BASIN.

      ...CLIMATOLOGICAL OUTLOOK...

SHORT RANGE...FOR THE NEXT 14 DAYS...SOUTHEAST WYOMING AND THE
WESTERN NEBRASKA PANHANDLE WILL AVERAGE ABOVE NORMAL TEMPERATURES
AND NEAR NORMAL PRECIPITATION

LONG RANGE...THROUGH APRIL...THE LA NINA PATTERN WILL CONTINUE TO
WEAKEN WITH NEUTRAL CONDITIONS EXPECTED BY MID SUMMER. THERE WILL
BE EQUAL CHANCES OF ABOVE...NEAR OR BELOW AVERAGE TEMPERATURES AND
PRECIPITATION OVER THE AREA.

...WATER SUPPLY OUTLOOK...NATIONAL WEATHER SERVICE/NATURAL RESOURCES
CONSERVATION SERVICE STREAMFLOW FORECASTS FOR SOUTHEASTERN WYOMING
AND THE NEBRASKA PANHANDLE AS OF JANUARY 1 2012.

                                            MOST PROBABLE FORECAST

                                             VOLUME        PERCENT
STREAM AND STATION             PERIOD        1000 AF       OF AVG
_________________              ______        _______      _______

NORTH PLATTE RIVER
  NORTHGATE NEAR, CO          APR-JUL           150           61
SEMINOE RES INFLOW            APR-JUL           500           63

  GLENDO BLO, WY              APR-JUL           560           59
  GUERNSEY RES BLO, WY        APR-JUL           560           58
  ALCOVA TO ORIN, WY GAIN     APR-JUL           169          111


DEER CREEK
  GLENROCK, WY                APR-JUL            39          105


ROCK CREEK
  ARLINGTON NEAR, WY          APR-JUL            40           70


LA PRELE CREEK
  LA PRELE RESERVOIR ABOVE    APR-JUL            22           91


ENCAMPMENT RIVER
  ENCAMPMENT NEAR, WY         APR-JUL           111           72


LARAMIE RIVER
  WOODS LANDING NEAR, WY      APR-JUL            95           85

LITTLE LARAMIE RIVER
  FILMORE NEAR, WY            APR-JUL            42           71


LITTLE SNAKE RIVER
  SLATER NR, CO               APR-JUL           182           76



      ...HYDROLOGIC OUTLOOK...

SNOW WATER EQUIVALENTS...SWES...ARE BELOW NORMAL FOR THE END OF JANUARY.
SNOW WATER EQUIVALENTS FROM THE MOUNTAIN SNOWPACK USUALLY PEAK AROUND
LATE APRIL TO EARLY MAY IN SOUTHEAST WYOMING. ALSO...30 TO 50 PERCENT
OF THE TOTAL SWES USUALLY OCCUR IN MARCH THROUGH THE BEGINNING OF MAY.
PEAK FLOW MAGNITUDES ARE VERY DEPENDENT UPON LATE SPRING TEMPERATURES
AND THE ENSUING MELT SCENARIO THAT DEVELOPS. GIVEN THE AMOUNT OF
SNOWPACK ALREADY IN THE MOUNTAINS ALONG WITH THE CLIMATOLOGICAL
PREDICTIONS FOR THE NEXT SEVERAL MONTHS...SWE PEAKS ARE EXPECTED TO
BE AT BELOW NORMAL LEVELS WITH THE EXCEPTION OF THE LITTLE SNAKE RIVER.
RUNOFF AND STREAMFLOW VOLUMES FOR THE LATE SPRING AND EARLY SUMMER ARE
LIKEWISE EXPECTED AT THIS TIME TO BE AT BELOW NORMAL LEVELS...WITH THE
EXCEPTION OF THE LITTLE SNAKE RIVER.  A MODERATE RISK OF SPRING SNOWMELT
FLOODING WILL RESULT ON THE LITTLE SNAKE RIVER AND SAVERY CREEK...WITH
A LOW RISK OF SPRING SNOWMELT FLOODING ON THE REST OF THE RIVERS
ORIGINATING IN THE SIERRA MADRE...SNOWY AND LARAMIE RANGES.

       ...FLOOD POTENTIAL OUTLOOK...

THE LITTLE SNAKE RIVER AND SAVERY CREEK AND THEIR TRIBUTARIES ARE ALL
EXPECTED TO EXPERIENCE A MODERATE SNOWMELT FLOOD POTENTIAL LATE THIS
SPRING AND EARLY THIS SUMMER.  THE OTHER RIVERS IN SOUTHEAST WYOMING AND
THE WESTERN NEBRASKA PANHANDLE ARE EXPECTED TO HAVE A LOW SNOWMELT FLOOD
POTENTIAL LATE THIS SPRING AND EARLY THIS SUMMER.

       ...ADDITIONAL INFORMATION...

FOR THE CURRENT WYOMING SPRING FLOOD POTENTIAL GRAPHIC...PLEASE REFER
TO...WWW.CRH.NOAA.GOV/RIW/HYDRO/FLOOD.PHP

FOR THE LATEST AVERAGE MONTHLY PRECIPITATION BY BASIN GRAPHICS...REFER
TO...WWW.CRH.NOAA.GOV/RIW/HYDRO/PRECIP.PHP

FOR THE CURRENT WYOMING WATER SUPPLY GRAPHIC...PLEASE REFER TO...
WWW.CRH.NOAA.GOV/RIW/HYDRO/WATER.PHP

FOR OTHER WEATHER AND RIVER INFORMATION IN SOUTHEAST WYOMING AND THE
WESTERN NEBRASKA PANHANDLE...REFER TO...WWW.WEATHER.GOV/CYS.

$$

WEILAND


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