…FLOOD AND WATER RESOURCES OUTLOOK…ISSUED JAN 24, 2013, FROM THE NATIONAL WEATHER SERVICE…

 
 THIS PROBABILISTIC FLOOD OUTLOOK IS FOR THE MISSOURI AND JAMES RIVER  BASINS OF WESTERN AND CENTRAL NORTH DAKOTA…COVERING THE TIME PERIOD OF LATE JANUARY THROUGH LATE APRIL.
 
 THE FOLLOWING MESSAGE HAS THREE SECTIONS…THE FIRST PROVIDES SOME  TEXT ON HIGHLIGHTS OF THIS PRODUCT AND CONDITIONS AFFECTING LOCAL HYDROLOGY. THE SECOND GIVES THE CURRENT AND NORMAL/HISTORICAL CHANCES OF RIVER LOCATIONS REACHING THEIR MINOR…MODERATE…AND MAJOR FLOOD CATEGORY. THE FINAL SECTION GIVES THE CURRENT CHANCE  OF RIVER LOCATIONS RISING ABOVE LISTED RIVER STAGES.
 
 
 …FLOOD OUTLOOK OVERVIEW HIGHLIGHTS…
 THIS IS THE FIRST OUTLOOK OF THE YEAR COVERING THE HISTORICALLY
 ACTIVE FLOOD SEASON OF MID-MARCH THROUGH LATE APRIL. THE RISK OF
 WIDESPREAD FLOODING ASSOCIATED WITH THE EVENTUAL SPRING MELT SEASON
 TENDS TO BE ON THE LOW END OF NORMAL BASED ON CURRENT CONDITIONS.
 HOWEVER…THERE IS STILL PLENTY OF TIME LEFT FOR WINTER TO ADD TO THE
 CURRENT SNOWPACK AND INCREASE THE OVERALL RISK OF SPRING FLOODING.
 
 …CURRENT CONDITIONS…
 WIDESPREAD MODERATE SNOWPACK OF 0.5 TO 1.4 INCHES OF WATER EQUIVALENT
 PUTS THE CURRENT SNOWPACK ON THE LOW END OF NORMAL. THE PAST FEW
 WEEKS OF MODEST SNOWFALLS HAVE GENERALLY BEEN AROUND HISTORICAL
 AVERAGES…BUT THE FEW WARM DAYS AND A GENERALLY DRY ATMOSPHERE HAVE
 KEPT THE WATER EQUIVALENT AVAILABLE ON THE GROUND RELATIVELY CONSTANT
 AS MOISTURE LOST TO THE ATMOSPHERE ROUGHLY EQUALS THAT RECEIVED.
 
 …WEATHER OUTLOOK…
 THE SHORTER 6 TO 10 AND 8 TO 14 DAY OUTLOOKS FAVOR COLDER THAN NORMAL
 TEMPERATURES WITH HIGHER THAN NORMAL PRECIPITATION. SIMILARLY THE
 THREE MONTH PERIOD OF FEBRUARY…MARCH…AND APRIL OUTLOOKS ALSO
 FAVOR COOLER AND WETTER THAN NORMAL OUTCOMES. THIS WOULD SUGGEST
 THAT WHILE THE CURRENT SNOWPACK IS ON THE LOW END OF THE NORMAL
 RANGE…THE REGION IS WITHIN EASY REACH OF A MORE ROBUST SNOWPACK
 HEADING INTO A POSSIBLY WETTER THAN NORMAL SPRING.
 
 …SUMMARY OF HYDROLOGIC CONDITIONS…
 IN THE MOST GENERAL OF TERMS…THE SMALL LAKES AND RIVERS ARE WELL
 WITHIN THE LOWER END OF NORMAL FOR THIS TIME OF YEAR. THE EFFECTS OF
 THE 2011 FLOODING ALONG THE MISSOURI RIVER STILL SEEM TO BE FELT
 ALONG THE RIVER WEST OF WILLISTON AND THAT REACH OF THE MISSOURI
 BETWEEN GARRISON DAM AND UPPER LAKE OAHE. RELATIVELY MINOR CHANGES IN
 FLOW HAVE CREATED SIGNIFICANT SWINGS IN RIVER LEVELS AT BOTH
 WILLISTON AND IN THE BISMARCK AREA.
 
 
 …LONG-RANGE PROBABILISTIC RIVER OUTLOOK BY FLOOD CATEGORY…
 
 THE TABLE BELOW GIVES BOTH THE CURRENT CHANCES (CS) AND THE
 NORMAL/HISTORICAL CHANCES (HS) FOR EXCEEDING THE MINOR…MODERATE
 AND MAJOR FLOOD STAGES AT THE RIVER FORECAST POINT LOCATIONS DURING
 THE VALID PERIOD OF THIS OUTLOOK.
 
 
 
                     JAMES AND MISSOURI RIVER BASINS
                     LONG-RANGE PROBABILISTIC OUTLOOK
 
         PROBABILITIES FOR MINOR…MODERATE AND MAJOR FLOODING
                     FROM  1/26/2013 TO 4/26/2013 Z
 
 TABLE 1                                  : CURRENT AND HISTORICAL
                                          : CHANCES OF EXCEEDING FLOOD
                                          : CATEGORY IN PERCENT (%)
                          CATEGORICAL     :
                       FLOOD STAGES (FT)  :  MINOR   MODERATE  MAJOR
 LOCATION            MINOR    MOD   MAJOR :  CS HS    CS HS    CS HS
 ——–            —— —— —— : — —  — —  — —
 LITTLE MUDDY CREEK…..
   WILLISTON           10.0   12.0   14.0 :  23  59   5  28   5  10
 LITTLE MISSOURI RIVER…..
   MARMARTH            18.0   23.0   30.0 :  5  5   5  5   5  5
   MEDORA              15.0   18.0   20.0 :  5  5   5  5   5  5
   WATFORD CITY        20.0   24.0   30.0 :  5  5   5  5   5  5
 KNIFE RIVER…..
   MANNING             15.0   17.0   20.0 :   5  21   5  5   5  5
 SPRING CREEK…..
   ZAP                 14.0   18.0   20.0 :  11  17    7   7   5  5
 KNIFE RIVER…..
   HAZEN               21.0   24.0   25.0 :  14  25   12  14    5   8
 HEART RIVER…..
   MANDAN              17.0   23.0   28.0 :  5   6   5  5   5  5
 APPLE CREEK…..
   MENOKEN             15.0   16.0   17.0 :  35  48   21  43    7  21
 CANNONBALL RIVER…..
   REGENT              22.0   24.0   26.0 :  5  5   5  5   5  5
 CEDAR CREEK…..
   RALEIGH             12.0   14.0   16.0 :  5  5   5  5   5  5
 CANNONBALL RIVER…..
   BREIEN              10.0   20.0   23.0 :  17  37   5  5   5  5
 BEAVER CREEK…..
   LINTON               9.0   11.0   13.0 :  5  34   5  21   5  15
 JAMES RIVER…..
   GRACE CITY          12.0   14.0   15.0 :  10  10    6   6    5   5
 PIPESTEM CREEK…..
   PINGREE              9.0   11.0   13.0 :  12  10    6   6   5  5
 JAMES RIVER…..
   LAMOURE             14.0   16.0   18.0 :   7   9   5   5   5  5
 
 LEGEND:
     CS    CONDITIONAL SIMULATION (OUTLOOK FOR CURRENT CONDITIONS)
     HS    HISTORICAL SIMULATION  ( ”       ”  NORMAL  CONDITIONS)
     FT    FEET ABOVE GAGE ZERO DATUM
 
 
 …LONG-RANGE PROBABILISTIC OUTLOOK BY RIVER STAGE…
 
 
 THE TABLE BELOW GIVES THE CURRENT 95 THROUGH 5 PERCENT CHANCES FOR
 EXCEEDING RIVER STAGES AT THE RIVER FORECAST POINT LOCATIONS DURING
 THE VALID PERIOD OF THIS OUTLOOK.
 
 EXAMPLE: DURING THE VALID TIME OF THIS OUTLOOK…THERE IS A
          50 PERCENT CHANCE FOR THE LITTLE MUDDY CREEK AT WILLISTON
          TO RISE ABOVE 8.4 FEET AND ONLY A 10 PERCENT CHANCE THAT
          IT WILL RISE ABOVE 11.2 FEET.
 
 
                     JAMES AND MISSOURI RIVER BASINS
                     LONG-RANGE PROBABILISTIC OUTLOOK
            PROBABILITIES FOR EXCEEDING LISTED RIVER STAGES
                      FROM  1/26/2013 TO 4/26/2013
 TABLE 2
 
 LOCATION              95%    90%    75%    50%    25%    10%    05%
 ——–            —— —— —— —— —— —— ——
 LITTLE MUDDY CREEK…..
   WILLISTON            7.0    7.1    7.8    8.4    9.6   11.2   11.5
 LITTLE MISSOURI RIVER…..
   MARMARTH             3.0    3.2    3.4    4.2    4.7    5.4    5.9
   MEDORA               3.3    3.8    4.4    5.2    5.8    6.9   10.0
   WATFORD CITY         1.0    1.4    2.0    2.7    3.5    4.9    8.3
 KNIFE RIVER…..
   MANNING              7.4    7.6    7.9    8.5    9.8   10.6   14.4
 SPRING CREEK…..
   ZAP                  5.8    6.1    6.3    6.8    8.8   14.8   18.8
 KNIFE RIVER…..
   HAZEN                3.6    4.9    5.5    7.0   15.6   24.2   24.9
 HEART RIVER…..
   MANDAN               1.8    2.2    2.4    3.1    6.6    9.5   10.3
 APPLE CREEK…..
   MENOKEN              7.0    7.3    8.3   10.4   15.7   16.3   19.7
 CANNONBALL RIVER…..
   REGENT               5.3    5.7    6.0    6.9    7.7    8.5    9.2
 CEDAR CREEK…..
   RALEIGH              3.6    3.7    4.0    4.4    4.9    6.2    6.9
 CANNONBALL RIVER…..
   BREIEN               6.0    6.6    7.5    8.1    8.6   11.2   13.2
 BEAVER CREEK…..
   LINTON               5.1    5.1    5.4    6.2    6.8    8.0    8.4
 JAMES RIVER…..
   GRACE CITY           4.6    4.7    5.2    5.6    6.2   12.0   15.5
 PIPESTEM CREEK…..
   PINGREE              5.0    5.1    5.4    5.8    6.3   10.3   11.6
 JAMES RIVER…..
   LAMOURE              7.0    7.1    7.3    7.5    8.0   11.6   15.2
 
 
 …THE OUTLOOK PRODUCTION PROCESS…
 
 THIS LONG RANGE PROBABILISTIC OUTLOOK IS BASED ON A SERIES OF PEAK
 RIVER LEVELS OR CRESTS TAKEN FROM THE FORECAST HYDROGRAPH RESULTS
 OF THE NWS ENSEMBLE STREAMFLOW PREDICTION MODEL (ESP). THE MODEL
 IS RUN FOR MULTIPLE SCENARIOS STARTING AT CURRENT RIVER…SNOW AND
 SOIL CONDITIONS AND USING 25 OR MORE YEARS OF PAST PRECIPITATION AND
 TEMPERATURE CONDITIONS IN THE HISTORICAL RECORD. THESE CRESTS CAN
 THEN BE RANKED FROM LOWEST TO HIGHEST…AND ASSIGNED AN
 EXCEEDANCE PROBABILITY. FOR EXAMPLE…FOR A SERIES OF 50 YEARS…
 THE LOWEST RANKED CREST HAS 49 CRESTS ABOVE IT AND SINCE 95 PERCENT
 OF THE CRESTS ARE ABOVE IT… IT IS ASSIGNED A 95 PERCENT
 PROBABILITY OF EXCEEDANCE (POE).
 
 THE PROBABILITIES CAN BE USED FOR RISK MANAGEMENT BY COMPARING THIS
 YEARS CURRENT TEMPERATURE AND PRECIPITATION OUTLOOKS WITH
 THOSE OF PAST YEARS USED IN THE HYDRO OUTLOOK. THEY CAN ALSO BE
 USED AS AN INDICATION OF THE RANGE OF CRESTS THAT MAY BE EXPECTED
 DURING THE VALID PERIOD OF THE OUTLOOK.
 
 BY PROVIDING A RANGE OF PEAK RIVER LEVEL PROBABILITIES..THE NWS IS
 IS CONTRIBUTING TO THE AREAS DECISION SUPPORT SERVICES THAT HELP
 WITH LONG RANGE FLOOD PLANNING AND RESPONSE READINESS.  THIS OUTLOOK
 IS A PART OF NOAA/S NATIONAL WEATHER SERVICE/S AHPS (ADVANCED
 HYDROLOGIC PREDICTION SERVICES).
 
 THIS OUTLOOK WAS PRODUCED USING PRECIPITATION AND TEMPERATURES
 FOR THE YEARS 1978 THROUGH 2002.
 
 . ADDITIONAL INFORMATION SOURCES…
 
 THE AHPS LONG RANGE PROBABILISTIC HYDROLOGIC OUTLOOKS ARE ISSUED
 NEAR THE END OF EACH MONTH. HOWEVER…SPRING FLOOD AND WATER
 RESOURCES OUTLOOKS ARE ISSUED SEVERAL TIMES DURING THE CRITICAL
 SPRING MELT PERIOD…USUALLY ON THURSDAYS BEGINNING IN LATE
 FEBRUARY OR EARLY MARCH AND ENDING IN EARLY APRIL…DEPENDING ON
 THE SPRING FLOODING CONDITIONS.
 
 THIS OUTLOOK IS ALSO PRESENTED AS GRAPHS OF THE PROBABILITY OF STAGE
 EXCEEDANCE FOR THE FULL PERIOD AND FOR WEEKLY INTERVALS DURING THE
 PERIOD. THESE GRAPHS…TOGETHER WITH EXPLANATIONS THAT HELP IN
 INTERPRETING THEM ARE AVAILABLE FROM THE NWS BISMARCK AHPS WEB
 PAGE ON THE INTERNET AT:
 
         WWW.WEATHER.GOV/BISMARCK OR WEATHER.GOV/BIS
 
 THEN CLICK ON THE “RIVERS AND LAKES AHPS”ON THE TAB ABOVE THE MAP
 …OR ON THE LINK IN THE BLUE-LEFT-HAND BANNER.
 
 CURRENT RIVER CONDITIONS FOR ALL FORECAST POINTS WITHIN THE SOURIS
 RIVER BASIN ARE AVAILABLE ON OUR WEB SITE…AS WELL AS THE FORECASTS
 WHEN THE RIVER AT THE FORECAST POINT IS IN OR NEAR FLOOD.
 
 IF YOU HAVE ANY QUESTIONS…CONTACT THE NWS AT 701-250-4495.
 
 PROBABILISTIC HYDROLOGIC OUTLOOKS WILL BE ISSUED MONTHLY THROUGHOUT