National Weather Service Text Product Display

Flood Potential Outlook
Issued by NWS Bismarck, ND
Versions: 1 2 3 4 5 6 7 8
000
FGUS73 KBIS 231919
ESFBIS
NDC009-013-023-049-061-069-075-079-101-251800-

PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE BISMARCK ND
219 PM CDT THU MAY 23 2013


...FLOOD AND WATER RESOURCES OUTLOOK...

THIS PROBABILISTIC FLOOD OUTLOOK IS FOR THE SOURIS (MOUSE) RIVER
BASIN OF WESTERN AND CENTRAL NORTH DAKOTA...COVER THE TIME PERIOD
OF LATE MAY THROUGH LATE AUGUST

THE FOLLOWING MESSAGE HAS FOUR 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 THIRD GIVES THE CURRENT CHANCES OF
RIVER LOCATIONS RISING ABOVE RIVER STAGES LISTED...AND THE FINAL
SECTION COVERS THE RISK OF RIVERS FALLING BELOW LISTED STAGES.

...FLOOD OUTLOOK OVERVIEW HIGHLIGHTS...

THE SOURIS RIVER FROM TOWNER THROUGH WESTHOPE IS EXPECTED TO REMAIN
ABOVE FLOOD STAGE THROUGH AT LEAST EARLY JUNE FROM CONTINUED
CONVEYANCE OF SPRING SNOW MELT...RESERVOIR RELEASES AND RECENT
RAINFALL...WITH A POSSIBLE LATE MAY RISE TO FLOOD STAGE FOR WILLOW
CREEK NEAR WILLOW CITY FROM MAY 18-21 RAINFALL. THE OUTLOOKS REFLECT
THESE FORECASTS FOR THESE LOCATIONS. FOR THE SOURIS RIVER FROM
SHERWOOD THROUGH VELVA...AND THE WINTERING RIVER...FLOOD RISK IS A
REFLECTION OF HISTORICAL NORMALS FROM SUMMER THUNDERSTORMS.

...CURRENT CONDITIONS...

FOLLOWING THE RAINFALL EVENT OF MAY 18-21 ACROSS WESTERN AND CENTRAL
NORTH DAKOTA WITH WIDESPREAD RAINFALL TOTALS OF 1 TO 3 INCHES FOR
THE SOURIS BASIN...SOIL MOISTURE LEVELS ARE ABOVE NORMAL FOR MUCH OF
THE AREA.

...WEATHER OUTLOOK...

AN ACTIVE WEATHER PERIOD IS EXPECTED FROM LATE MAY INTO EARLY JUNE
WITH ABOVE NORMAL PRECIPITATION POSSIBLE WITH SEVERAL ROUNDS OF
THUNDERSTORMS. THERE IS AN EQUAL CHANCE OF ABOVE...BELOW...AND NEAR
NORMAL TEMPERATURES AND PRECIPITATION BY MID JUNE THROUGH AUGUST.

...SUMMARY OF HYDROLOGIC CONDITIONS...

AS STATED ABOVE...THE SOURIS RIVER FROM TOWNER THROUGH WESTHOPE IS
EXPECTED TO REMAIN ABOVE FLOOD STAGE THROUGH AT LEAST EARLY JUNE
FROM CONTINUED CONVEYANCE OF SPRING SNOW MELT...RESERVOIR RELEASES
AND RECENT RAINFALL...WITH A POSSIBLE LATE MAY RISE TO FLOOD STAGE
FOR WILLOW CREEK NEAR WILLOW CITY FROM MAY 18-21 RAINFALL.
OTHERWISE...STREAMFLOWS ARE ABOVE NORMAL FROM RECENT RAINFALL BUT
WITHIN THEIR BANKS ACROSS THE REMAINDER OF THE BASIN.


...LONG-RANGE PROBABILISTIC RIVER OUTLOOK BY FLOOD CATEGORY...


                           SOURIS RIVER BASIN
                    LONG-RANGE PROBABILISTIC OUTLOOK
             VALID FROM MAY 27, 2013  TO AUGUST 25, 2013

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.

        PROBABILITIES FOR MINOR...MODERATE AND MAJOR FLOODING
                     FROM  5/27/2013 TO 8/25/2013

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
--------            ------ ------ ------ : --- ---  --- ---  --- ---
DES LACS RIVER.....
  FOXHOLM             16.0   18.0   19.0 :  <5  <5   <5  <5   <5  <5
SOURIS RIVER.....
  SHERWOOD            18.0   20.0   25.0 :  <5  <5   <5  <5   <5  <5
  SOURIS NR FOXHOLM   10.0   13.0   15.0 :  29  19   <5  13   <5  <5
  MINOT 4NW           14.0   17.0   22.0 :  <5  <5   <5  <5   <5  <5
  MINOT             1549.0 1551.0 1555.0 :  <5  <5   <5  <5   <5  <5
  LOGAN               34.0   36.0   38.0 :  11  <5   <5  <5   <5  <5
  SAWYER              22.0   24.0   26.0 :  11  <5   <5  <5   <5  <5
  VELVA             1505.0 1510.0 1515.0 :  11  <5   <5  <5   <5  <5
WINTERING RIVER.....
  KARLSRUHE            7.0    9.0   10.0 :  21  <5   <5  <5   <5  <5
SOURIS RIVER.....
  TOWNER              52.0   54.0   56.0 : >95  27  >95  18   <5  <5
  BANTRY              11.0   12.0   14.0 : >95  24  >95  21   <5  <5
WILLOW CREEK.....
  WILLOW CITY         10.0   14.0   16.0 : >95   8    8  <5   <5  <5
SOURIS RIVER.....
  WESTHOPE            10.0   14.0   16.0 : >95  24   18  <5   11  <5

LEGEND:
    CS  =  CONDITIONAL SIMULATION (OUTLOOK FOR CURRENT CONDITIONS)
    HS  =  HISTORICAL SIMULATION  (HISTORICAL RISK FOR THIS SEASON)
    FT  =  FEET ABOVE GAGE ZERO DATUM


...LONG-RANGE PROBABILISTIC OUTLOOK BY RIVER STAGE...


                          SOURIS RIVER BASIN
                    LONG-RANGE PROBABILISTIC OUTLOOK
              VALID OCTOBER 1, 2012 - DECEMBER 30, 2012

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
         95 PERCENT CHANCE FOR THE SOURIS RIVER AT SHERWOOD TO
         RISE ABOVE XXXX FEET AND ONLY A 15 PERCENT CHANCE THAT
         IT WILL RISE ABOVE XXXX FEET.

           PROBABILITIES FOR EXCEEDING LISTED RIVER STAGES
                     FROM  5/27/2013 TO 8/25/2013
TABLE 2

LOCATION              95%    90%    75%    50%    25%    10%    05%
--------             -----  -----  -----  -----  -----  -----  -----
DES LACS RIVER.....
  FOXHOLM              6.9    6.9    6.9    7.1    8.7   11.2   13.2
SOURIS RIVER.....
  SHERWOOD             5.9    5.9    5.9    6.0    8.6   11.0   14.4
  SOURIS NR FOXHOLM    9.6    9.6    9.6    9.6   10.2   11.6   13.9
  MINOT 4NW            9.2    9.2    9.2    9.3    9.8   11.3   13.7
  MINOT             1542.9 1542.9 1542.9 1543.0 1543.3 1544.0 1545.6
  LOGAN               32.5   32.5   32.5   32.6   33.0   34.4   35.9
  SAWYER              20.4   20.4   20.4   20.4   20.8   22.8   24.6
  VELVA             1503.5 1503.5 1503.5 1503.6 1503.8 1505.5 1507.1
WINTERING RIVER.....
  KARLSRUHE            5.3    5.3    5.3    5.3    6.5    7.8    8.2
SOURIS RIVER.....
  TOWNER              54.6   54.6   54.6   54.6   54.9   55.7   56.2
  BANTRY              12.6   12.6   12.6   12.6   12.8   13.5   14.0
WILLOW CREEK.....
  WILLOW CITY         13.4   13.4   13.4   13.4   13.4   14.0   15.2
SOURIS RIVER.....
  WESTHOPE            12.8   12.8   12.8   12.8   13.2   16.3   18.0



...LONG-RANGE PROBABILISTIC OUTLOOK BY RIVER STAGE...


                          SOURIS RIVER BASIN
                    LONG-RANGE PROBABILISTIC OUTLOOK
              VALID OCTOBER 1, 2012 - DECEMBER 30, 2012

THE TABLE BELOW GIVES THE CURRENT 95 THROUGH 5 PERCENT CHANCES FOR
THE RIVERS TO FALL BELOW THE LISTED 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
         95 PERCENT CHANCE FOR THE SOURIS RIVER AT SHERWOOD TO
         REMAIN ABOVE XXXX FEET AND ONLY A 15 PERCENT CHANCE THAT
         IT WILL FALL BELOW XXXX FEET.

         PROBABILITIES FOR FALLING BELOW LISTED RIVER STAGES
                        5/27/2013 - 8/25/2013

TABLE 3

LOCATION              95%    90%    75%    50%    25%    10%    05%
--------             -----  -----  -----  -----  -----  -----  -----
DES LACS RIVER.....
  FOXHOLM              5.9    5.8    5.6    5.5    5.5    5.5    5.5
SOURIS RIVER.....
  SHERWOOD             2.5    2.3    1.8    1.6    1.5    1.5    1.5
  SOURIS NR FOXHOLM    4.5    4.5    4.5    4.5    4.5    4.5    4.5
  MINOT 4NW            5.5    5.0    4.3    4.3    4.3    4.3    4.3
  MINOT             1541.2 1540.8 1538.4 1537.9 1537.9 1537.9 1537.9
  LOGAN               23.9   23.6   20.9   20.6   20.6   20.6   20.5
  SAWYER               9.3    8.9    6.7    6.5    6.5    6.4    6.4
  VELVA             1491.9 1491.8 1490.5 1490.2 1490.2 1490.1 1490.1
WINTERING RIVER.....
  KARLSRUHE            2.9    2.5    2.2    1.2    1.2    1.2    1.2
SOURIS RIVER.....
  TOWNER              48.8   48.4   46.2   45.4   45.1   45.1   45.1
  BANTRY               7.2    6.3    4.1    3.4    3.2    3.2    3.2
WILLOW CREEK.....
  WILLOW CITY          5.4    4.9    4.7    4.6    4.6    4.6    4.6
SOURIS RIVER.....
  WESTHOPE             8.3    7.9    7.4    6.9    6.8    6.8    6.8


...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 NEARLY 50 YEARS OF PAST PRECIPITATION AND
TEMPERATURE CONDITIONS IN THE HISTORICAL RECORD. THESE CRESTS CAN
THEN
BE RANKED FROM LOWEST TO HIGHEST...AND THEN BE 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 1948 THROUGH 2006.

...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.


$$

AYD
National Weather Service Weather Forecast Office
