National Weather Service Weather Forecast Office

PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE CHEYENNE WY
944 AM MST THU JAN 24 2013

...SPRING 2013 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.

...LOW SNOWMELT FLOOD POTENTIAL IS EXPECTED FOR ALL RIVERS AND STREAMS
IN SOUTHEAST WYOMING.

...ABNORMALLY DRY CONDITIONS EXIST AS OF MID JANUARY FOR MOST OF
SOUTHEAST WYOMING AND THE NEBRASKA PANHANDLE.  EXCEPTIONAL OR
EXTREME DROUGHT CONDITIONS PERSIST OVER MUCH OF THE REGION.  THE
EXCEPTION IS EXTREME SOUTHEAST WYOMING WHERE SEVERE DROUGHT WAS
OCCURRING. THOSE CONDITIONS ARE EXPECTED TO CHANGE LITTLE THROUGH
APRIL.

THIS OUTLOOK IS VALID THROUGH THE END OF JUNE.  THE NEXT SNOWMELT
AND WATER RESOURCES OUTLOOK WILL BE ISSUED AROUND FEBRUARY 21.

     ...CURRENT HYDROLOGIC CONDITIONS...

THE RIVERS AND STREAMS IN SOUTHEAST WYOMING WERE AT OR BELOW AVERAGE
WATER LEVELS IN MID JANUARY.

FROM OCTOBER 2012 THROUGH MID JANUARY 2013...PRECIPITATION WAS BELOW
NORMAL OVER SOUTHEAST WYOMING AND THE WESTERN NEBRASKA PANHANDLE.
TEMPERATURES FOR THAT TIME PERIOD WERE ABOVE NORMAL OVER THE REGION.

THE RESULTING SNOWPACK FROM SNOTEL SITES AS OF JANUARY 22 2013 WAS
BELOW NORMAL OVER SOUTHEAST WYOMING. AS OF THAT DATE...ALL BASINS
HAD 75 PERCENT OR LESS OF NORMAL SNOW WATER EQUIVALENT.  THE LARGEST
BASIN SNOW WATER EQUIVALENT VALUE ON THAT DATE 69 PERCENT OF NORMAL
IN THE LITTLE SNAKE RIVER BASIN.

      ...CLIMATOLOGICAL OUTLOOK...

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

LONG RANGE...THROUGH APRIL...THE MAJORITY OF THE STATISTICAL AND
DYNAMICAL MODELS ARE PREDICTING BORDERLINE ENSO-NEUTRAL/WEAK EL NINO
CONDITIONS THROUGH THE EARLY PART OF THIS YEAR. THE CLIMATE
PREDICTION CENTER INDICATES EQUAL CHANCES OF ABOVE NORMAL...NORMAL
AND BELOW NORMAL PRECIPITATION AND TEMPERATURES THROUGH APRIL.

...WATER SUPPLY OUTLOOK...NATIONAL WEATHER SERVICE/NATURAL RESOURCES
CONSERVATION SERVICE STREAMFLOW FORECASTS FOR SOUTHEASTERN WYOMING
AND THE NEBRASKA PANHANDLE AS OF JANUARY 1 2013.

                                            MOST PROBABLE FORECAST

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

NORTH PLATTE RIVER            APR-JUL           155           69
  NORTHGATE NEAR, CO          APR-SEP           173           69
SEMINOE RES INFLOW, WY        APR-JUL           490           69
SEMINOE RES INFLOW            APR-SEP           530           69

  GLENDO BLO, WY              APR-JUL           475           58
  GLENDO BLO, WY              APR-SEP           500           59
  GUERNSEY RES BLO, WY        APR-JUL           470           57
  GUERNSEY RES BLO, WY        APR-SEP           510           60
  ALCOVA TO ORIN, WY GAIN     APR-JUL           M             M
  ALCOVA TO ORIN, WY GAIN     APR-SEP           M             M

DEER CREEK
  GLENROCK, WY                APR-JUL           M             M
                              APR-SEP           M             M
ROCK CREEK
  ARLINGTON NEAR, WY          APR-SEP            37           76
  ARLINGTON NEAR, WY          APR-SEP            39           75

LA PRELE CREEK
  LA PRELE RESERVOIR ABOVE    APR-SEP           M             M

ENCAMPMENT RIVER
  ENCAMPMENT NEAR, WY         APR-JUL           107           83
  ENCAMPMENT NEAR, WY         APR-SEP           115           83

LARAMIE RIVER
  WOODS LANDING NEAR, WY      APR-JUL            92           80
  WOODS LANDING NEAR, WY      APR-SEP           101           80

LITTLE LARAMIE RIVER
  FILMORE NEAR, WY            APR-JUL            38           75
  FILMORE NEAR, WY            APR-SEP            40           73

LITTLE SNAKE RIVER   XXX
  SLATER NR, CO               APR-JUL           105           67

      ...HYDROLOGIC OUTLOOK...

SNOW WATER EQUIVALENTS...SWES...ARE BELOW NORMAL FOR MID 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.

RUNOFF AND STREAMFLOW VOLUMES FOR THE LATE SPRING AND EARLY SUMMER
ARE LIKEWISE EXPECTED AT THIS TIME TO BE AT BELOW NORMAL LEVELS.
AS OF MID JANUARY...A LOW RISK OF SPRING SNOWMELT FLOODING WILL
RESULT ON ALL RIVERS AND STREAMS IN SOUTHEAST WYOMING.

       ...FLOOD POTENTIAL OUTLOOK...

AS OF JANUARY 22...STREAMS AND RIVERS ACROSS SOUTHEAST WYOMING 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