751
FGUS73 KBIS 291831
ESFBIS
NDC009-013-023-049-069-075-079-101-311800-
PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE BISMARCK ND
131 PM CDT FRI AUG 29 2025
..FLOOD AND WATER RESOURCES OUTLOOK
THIS FLOOD AND WATER RESOURCES OUTLOOK IS FOR THE SOURIS RIVER BASIN
OF NORTH DAKOTA, COVERING THE PERIOD OF 01 SEPTEMBER, 2025 THROUGH
30 NOVEMBER, 2025.
THE FOLLOWING MESSAGE HAS FOUR SECTIONS. THE FIRST PROVIDES SOME
TEXT ON THE HIGHLIGHTS OF THIS OUTLOOK AND CONDITIONS AFFECTING THE
LOCAL HYDROLOGY. THE SECOND SECTION GIVES THE CURRENT AND HISTORICAL
RISKS OF FLOODING AS DETERMINED BY THE ENSEMBLE STREAMFLOW FORECAST
MODEL OF THE NATIONAL WEATHER SERVICE. THE THIRD SECTION GIVES THE
CURRENT PROBABILITIES FOR REACHING FLOOD STAGE AT THE LISTED
FORECAST LOCATIONS. AND FINALLY, THE FOURTH SECTION COVERS THE RISK
OF THE RIVER SITES FALLING BELOW THE LISTED STAGES.
..FLOOD OUTLOOK HIGHLIGHTS
ALL FORECAST LOCATIONS IN THE SOURIS RIVER BASIN OF NORTH DAKOTA ARE
NEAR TO SOMEWHAT BELOW NORMAL RISK OF FLOODING FOR THIS TIME OF YEAR.
..SNOWPACK CONDITIONS
NO SNOW EXISTS IN THE MISSOURI AND JAMES RIVER BASINS OF NORTH
DAKOTA.
..CURRENT DROUGHT CONDITIONS
RAINFALL OVER THE PAST MONTH HAS EFFECTIVELY REMOVED ALL DROUGHT
DESIGNATIONS WITHIN THE SOURIS RIVER BASIN OF NORTH DAKOTA.
..RESERVOIRS AND NATURAL WETLANDS
RESERVOIRS AND NATURAL WETLANDS CONTINUE TO FARE REASONABLY WELL
DESPITE THE DRY SPRING.
..SOIL CONDITIONS
WHILE DROUGHT DESIGNATIONS HAVE BEEN REMOVED, WARM AND DRY WEATHER
OVER THE PAST COUPLE OF WEEKS HAVE STARTED TO HAVE A NEGATIVE EFFECT
ON SOIL MOISTURE. MUCH OF THE SOURIS RIVER BASIN IN NORTH DAKOTA IS
NOW SHOWING DRIER THAN NORMAL SOILS THROUGHOUT THE UPPER 100
CENTIMETERS OF THE SOIL.
..WEATHER OUTLOOK
THE NEAR TERM 6-10 AND 8-14 DAY WEATHER OUTLOOKS REFLECT A BIT OF A
TRANSITION FROM COOLER THAN NORMAL TO SLIGHTLY ABOVE NORMAL
TEMPERATURES WITH BELOW NORMAL PRECIPITATION IN THE NEAR TERM, WHICH
TRANSITIONS TOWARDS MORE NEAR NORMAL IN THE LATER PERIOD. LOOKING A
LITTLE LONGER TERM AT THE ONE-MONTH OUTLOOKS FOR SEPTEMBER, THERE IS
A SLIGHT FAVORING FOR ABOVE NORMAL TEMPERATURES WITH BELOW NORMAL
PRECIPITATION IN THE WESTERN HALF OF THE BASIN.
LOOKIING EVEN LONGER INTO THE FUTURE, THE THREE-MONTH OUTLOOKS
COVERING SEPTEMBER, OCTOBER AND NOVEMBER HAVE THE REGION IN THE
EQUAL CHANCES CATEGORY FOR ABOVE NORMAL, NEAR NORMAL, OR BELOW
NORMAL TEMPERATURES AND PRECIPITATION. THIS LONGER TERM UNCERTAINTY
IS LIKELY ASSOCIATED WITH THE SLIGHT FAVORING FOR A TRANSITION TO A
LA NINA WEATHER PATTERN SOMETIME IN THE LATE FALL TO EARLY WINTER.
IN TABLE 1 BELOW, THE CURRENT (CS) AND HISTORICAL (HS) OR NORMAL
PROBABILITIES OF EXCEEDING MINOR...MODERATE...AND MAJOR FLOOD STAGE
ARE LISTED FOR THE VALID TIME PERIOD.
CS VALUES INDICATE THE PROBABILITY OF REACHING A FLOOD CATEGORY
BASED ON CURRENT CONDITIONS.
HS VALUES INDICATE THE PROBABILITY OF REACHING A FLOOD CATEGORY
BASED ON HISTORICAL OR NORMAL CONDITIONS.
WHEN THE VALUE OF CS IS GREATER THAN HS...THE PROBABILITY OF
EXCEEDING THAT LEVEL IS HIGHER THAN NORMAL. WHEN THE VALUE OF CS IS
LESS THAN HS...THE PROBABILITY OF EXCEEDING THAT LEVEL IS LOWER
THAN NORMAL.
..TABLE 1--PROBABILITIES FOR MINOR...MODERATE AND MAJOR FLOODING
VALID PERIOD: 09/01/2025 - 11/30/2025
: CURRENT AND HISTORICAL
: CHANCES OF EXCEEDING
: FLOOD CATEGORIES
: AS A PERCENTAGE (%)
CATEGORICAL :
FLOOD STAGES (FT) : MINOR MODERATE MAJOR
LOCATION MINOR MOD MAJOR : CS HS CS HS CS HS
-------- ----- ----- ----- : --- --- --- --- --- ---
:DES LACS
FOXHOLM 1651.0 1653.0 1654.0 : <5 <5 <5 <5 <5 <5
:SOURIS
SHERWOOD 1623.0 1625.0 1630.0 : <5 <5 <5 <5 <5 <5
FOXHOLM 1573.0 1576.0 1578.0 : <5 <5 <5 <5 <5 <5
MINOT 1562.0 1565.0 1570.0 : <5 <5 <5 <5 <5 <5
MINOT 1551.0 1553.0 1557.0 : <5 <5 <5 <5 <5 <5
LOGAN 1536.0 1538.0 1540.0 : <5 <5 <5 <5 <5 <5
SAWYER 1524.0 1526.0 1528.0 : <5 <5 <5 <5 <5 <5
VELVA 1507.0 1512.0 1517.0 : <5 <5 <5 <5 <5 <5
:WINTERING
KARLSRUHE 1509.0 1511.0 1512.0 : <5 <5 <5 <5 <5 <5
:SOURIS
TOWNER 1454.0 1456.0 1458.0 : <5 <5 <5 <5 <5 <5
BANTRY 1440.0 1441.0 1443.0 : <5 <5 <5 <5 <5 <5
:WILLOW CREEK
WILLOW CITY 1442.0 1446.0 1448.0 : <5 6 <5 <5 <5 <5
:SOURIS
WESTHOPE 1414.0 1418.0 1420.0 : <5 <5 <5 <5 <5 <5
LEGEND
CS = CONDITIONAL SIMULATION (CURRENT OUTLOOK)
HS = HISTORICAL SIMULATION
FT = FEET
IN TABLE 2 BELOW...THE 95 THROUGH 5 PERCENT COLUMNS INDICATE THE
PROBABILITY OF EXCEEDING THE LISTED STAGE LEVELS (FT) FOR THE VALID
TIME PERIOD.
..TABLE 2--EXCEEDANCE PROBABILITIES
CHANCE OF EXCEEDING STAGES
AT SPECIFIC LOCATIONS
VALID PERIOD: 09/01/2025 - 11/30/2025
LOCATION 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:DES LACS
FOXHOLM 1639.0 1639.0 1639.0 1639.0 1639.8 1640.9 1642.4
:SOURIS
SHERWOOD 1606.4 1606.4 1606.4 1606.5 1607.0 1611.1 1612.7
FOXHOLM 1566.5 1566.5 1566.5 1566.5 1566.5 1570.7 1570.9
MINOT 1550.7 1550.7 1550.7 1550.7 1551.2 1553.8 1554.5
MINOT 1541.2 1541.2 1541.2 1541.2 1541.5 1542.6 1543.0
LOGAN 1520.0 1520.0 1520.0 1520.0 1521.3 1526.1 1527.2
SAWYER 1507.0 1507.0 1507.0 1507.0 1508.0 1512.0 1513.3
VELVA 1490.4 1490.4 1490.4 1490.4 1491.7 1495.9 1498.0
:WINTERING
KARLSRUHE 1503.0 1503.0 1503.0 1503.0 1504.0 1504.9 1506.1
:SOURIS
TOWNER 1445.6 1445.6 1445.6 1445.6 1446.1 1451.7 1453.7
BANTRY 1431.4 1431.4 1431.4 1431.4 1431.9 1436.9 1439.8
:WILLOW CREEK
WILLOW CITY 1436.1 1436.1 1436.1 1436.8 1437.1 1437.7 1438.2
:SOURIS
WESTHOPE 1410.5 1410.5 1410.5 1410.5 1410.6 1412.0 1413.0
IN TABLE 3 BELOW...THE 95 THROUGH 5 PERCENT COLUMNS INDICATE THE
PROBABILITY OF FALLING BELOW THE LISTED STAGE LEVELS (FT) FOR
THE VALID TIME PERIOD.
..TABLE 3--NONEXCEEDANCE PROBABILITIES
CHANCE OF FALLING BELOW STAGES
AT SPECIFIC LOCATIONS
VALID PERIOD: 09/01/2025 - 11/30/2025
LOCATION 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:DES LACS
FOXHOLM 0.0 0.0 0.0 0.0 0.0 0.0 0.0
:SOURIS
SHERWOOD 0.0 0.0 0.0 0.0 0.0 0.0 0.0
FOXHOLM 0.0 0.0 0.0 0.0 0.0 0.0 0.0
MINOT 0.0 0.0 0.0 0.0 0.0 0.0 0.0
MINOT 0.0 0.0 0.0 0.0 0.0 0.0 0.0
LOGAN 0.0 0.0 0.0 0.0 0.0 0.0 0.0
SAWYER 0.0 0.0 0.0 0.0 0.0 0.0 0.0
VELVA 0.0 0.0 0.0 0.0 0.0 0.0 0.0
:WINTERING
KARLSRUHE 0.0 0.0 0.0 0.0 0.0 0.0 0.0
:SOURIS
TOWNER 0.0 0.0 0.0 0.0 0.0 0.0 0.0
BANTRY 0.0 0.0 0.0 0.0 0.0 0.0 0.0
:WILLOW CREEK
WILLOW CITY 0.0 0.0 0.0 0.0 0.0 0.0 0.0
:SOURIS
WESTHOPE 0.0 0.0 0.0 0.0 0.0 0.0 0.0
THESE LONG-RANGE PROBABILISTIC OUTLOOKS CONTAIN FORECAST VALUES THAT
ARE CALCULATED USING MULTIPLE SEASON SCENARIOS FROM 30 OR MORE YEARS
OF CLIMATOLOGICAL DATA...INCLUDING CURRENT CONDITIONS OF THE
RIVER...SOIL MOISTURE...SNOW COVER AND 30 TO 90 DAY LONG-RANGE
OUTLOOKS OF TEMPERATURE AND PRECIPITATION. BY PROVIDING A RANGE
OF PROBABILITIES...THE LEVEL OF RISK ASSOCIATED WITH LONG-RANGE
PLANNING DECISIONS CAN BE DETERMINED. THESE PROBABILISTIC
FORECASTS ARE PART OF THE NATIONAL WEATHER SERVICE'S ADVANCED
HYDROLOGIC PREDICTION SERVICE.
VISIT OUR WEB SITE WEATHER.GOV/BIS FOR MORE WEATHER AND WATER
INFORMATION.
THE NEXT OUTLOOK WILL BE ISSUED BY THE END OF SEPTEMBER.
SCHLAG
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