NATIONAL WEATHER SERVICE BISMARCK ND
 1129 AM CDT THU MAR 21 2013
 
 
 …SPRING FLOOD AND WATER RESOURCES OUTLOOK…
 
 THIS PROBABILISTIC FLOOD OUTLOOK IS FOR THE MISSOURI AND JAMES RIVER
 BASINS OF WESTERN AND CENTRAL NORTH DAKOTA…COVERING THE TIME PERIOD
 OF OCTOBER THROUGH LATE DECEMBER.
 
 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 CHANCES
 OF RIVER LOCATIONS RISING ABOVE LISTED RIVER STAGES.
 
 
 …FLOOD OUTLOOK OVERVIEW HIGHLIGHTS…
 NOT ENOUGH HAS CHANGED OVER THE PAST WEEK TO WARRANT REDOING THE
 PROBABILITY TABLES…THE NUMBERS ISSUED LAST WEEK ARE THE SAME AS
 THOSE BELOW. HOWEVER…THE TEXT BELOW REFLECTS LATEST
 CONDITIONS…OBSERVATIONS…AND EXPECTATIONS.
 
 …CURRENT CONDITIONS…
 AFTER A SHORT AND VERY WARM SPELL LATE LAST WEEK…AREAS SOUTH AND
 WEST OF BISMARCK SAW A SIGNIFICANT FRACTION OF ITS MODEST SNOWPACK
 MELT AND RUNOFF. THE MAJORITY OF THE SNOW REMAINING IN THE MISSOURI
 RIVER BASIN TENDS TO BE THAT NEAREST LAKE SAKAKAWEA FROM BASICALLY
 WILLISTON DOWN THROUGH GARRISON ON THE NORTH SIDE OF THE LAKE. THE
 JAMES RIVER BASIN HAS ALSO RETAINED MOST OF ITS SNOW WITH VERY
 LITTLE MELT HAVING OCCURED SO FAR THIS YEAR. IN THE NORTHERNMOST
 AREAS…VERY LITTLE PROGRESS HAS BEEN MADE IN THE RIPENING
 OF THE SNOWPACK AND SNOWPACK CONDITIONS ARE MORE SIMILAR TO WHAT IS
 COMMONLY SEEN IN JANUARY AND FEBRUARY THAN WHAT IS NORMAL FOR THIS
 CLOSE TO APRIL.
 
 …WEATHER OUTLOOK…
 AN INCOMING SYSTEM TODAY THROUGH EARLY SATURDAY WILL MOST LIKELY
 AFFECT WESTERN NORTH DAKOTA WITH 3 TO 5 INCHES OF SNOW POSSIBLE IN
 THE NORTHWESTERN CORNER OF THE STATE WITH 2 TO 4 INCHES FAVORED IN
 THE SOUTHWEST. AFTER THIS SYSTEM PASSES THROUGH…THE 6 TO 10 AND 8
 TO 14 DAY OUTLOOKS SUGGEST BELOW NORMAL TO NEAR NORMAL TEMPERATURES
 WITH BELOW NORMAL PRECIPITATION. THIS IS FAVORED TO TRANSITION INTO
 A NEAR NORMAL TEMPERATURE REGIME FOR APRIL WITH A SLIGHTLY ABOVE
 NORMAL PRECIPITATION PATTERN.
 
 …SUMMARY OF HYDROLOGIC CONDITIONS…
 MOST RIVERS AND STREAMS REMAIN ICE COVERED. NOT ENOUGH WARM
 TEMPERATURES OR RUNOFF IS EXPECTED OVER THE NEXT COUPLE WEEKS TO
 EFFECTIVELY REMOVE THE ICE.
 
 
 …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  3/9/2013 TO 6/7/2013 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 :  22  63   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   7   5   6   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  18   5  5   5  5
 SPRING CREEK…..
   ZAP                 14.0   18.0   20.0 :   5  22   5   7   5  5
 KNIFE RIVER…..
   HAZEN               21.0   24.0   25.0 :   5  25   5  11   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 :  32  55   18  47    5  25
 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 :  20  38   5  5   5  5
 BEAVER CREEK…..
   LINTON               9.0   11.0   13.0 :  34  38   27  29   14  24
 JAMES RIVER…..
   GRACE CITY          12.0   14.0   15.0 :  5  10   5   6   5   5
 PIPESTEM CREEK…..
   PINGREE              9.0   11.0   13.0 :   7  12   5   6   5  5
 JAMES RIVER…..
   LAMOURE             14.0   16.0   18.0 :  5   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 8.3 FEET AND ONLY A 10 PERCENT     
          CHANCE THAT IT WILL RISE ABOVE 10.8 FEET.
 
 
                     JAMES AND MISSOURI RIVER BASINS
                     LONG-RANGE PROBABILISTIC OUTLOOK
            PROBABILITIES FOR EXCEEDING LISTED RIVER STAGES
                       FROM  3/9/2013 TO 6/7/2013
 TABLE 2
 
 LOCATION              95%    90%    75%    50%    25%    10%    05%
 ——–            —— —— —— —— —— —— ——
 LITTLE MUDDY CREEK…..
   WILLISTON            6.1    6.5    7.3    8.3    9.8   10.8   10.8
 LITTLE MISSOURI RIVER…..
   MARMARTH             1.8    1.8    1.9    3.0    3.9    6.4    9.9
   MEDORA               1.9    1.9    2.1    3.3    4.5    7.3   10.4
   WATFORD CITY        -0.9   -0.5    0.3    1.1    2.5    4.6    6.4
 KNIFE RIVER…..
   MANNING              6.2    6.2    6.2    7.3    8.9   10.1   10.7
 SPRING CREEK…..
   ZAP                  5.1    5.2    5.6    6.4    9.7   11.1   14.5
 KNIFE RIVER…..
   HAZEN                1.3    2.0    3.6    6.6   10.7   16.0   21.0
 HEART RIVER…..
   MANDAN               1.0    1.4    2.0    3.0    5.6    7.6    9.7
 APPLE CREEK…..
   MENOKEN              5.6    5.8    6.7   11.5   15.7   16.3   17.0
 CANNONBALL RIVER…..
   REGENT               3.2    3.3    4.6    6.7    8.3    9.3   10.4
 CEDAR CREEK…..
   RALEIGH              2.3    2.3    2.8    4.3    5.4    6.4    6.8
 CANNONBALL RIVER…..
   BREIEN               5.1    5.1    5.6    7.3    9.6   11.6   13.2
 BEAVER CREEK…..
   LINTON               6.6    6.8    6.9    8.0   12.0   13.6   14.6
 JAMES RIVER…..
   GRACE CITY           4.4    4.5    4.8    5.1    5.6    6.7    8.1
 PIPESTEM CREEK…..
   PINGREE              5.1    5.1    5.2    5.6    6.7    7.8   10.1
 JAMES RIVER…..
   LAMOURE              7.1    7.1    7.3    7.6    8.2    9.7   10.4
 
 
 …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
 THE REST OF THE YEAR DURING THE LATER PART OF THE MONTH OR AS
 CONDITIONS WARRANT.