623
FGUS73 KBIS 241808
ESFBIS
NDC001-007-011-015-021-025-029-031-033-037-041-043-045-047-051-053-
055-057-059-061-065-083-085-087-089-093-103-105-261815-
PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE BISMARCK ND
108 PM CDT THU APR 24 2025
..FLOOD AND WATER RESOURCES OUTLOOK
THIS FLOOD AND WATER RESOURCES OUTLOOK IS FOR THE MISSOURI
AND JAMES RIVER BASINS OF NORTH DAKOTA, COVERING THE PERIOD OF 26
APRIL THROUGH 25 JULY, 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
WITH THE EXCEPTION OF THE MISSOURI RIVER NEAR WILLISTON ALL OTHER
FORECAST LOCATIONS ARE ON THE BACKSIDE OF THE SPRING MELT SEASON,
ALL FORECAST LOCATIONS ARE APPROXIMATELY NEAR NORMAL RISK TO WELL
BELOW NORMAL RISK OF FLOODING FOR THIS TIME OF YEAR.
..SNOWPACK CONDITIONS
NO APPRECIABLE SNOW REMAINS IN THE MISSOURI AND JAMES RIVER BASINS
OF NORTH DAKOTA.
..THE MISSOURI AND YELLOWSTONE RIVERS WEST OF WILLISTON
THE HEADWATERS AREAS FOR BOTH THE YELLOWSTONE AND MISSOURI RIVERS
STILL CONTAINS AN APPRECIABLE AMOUNT OF ITS SNOWPACK, BUT WITHOUT
SIGNIFICANT RAINS TO BOOST RUNOFF THE RISK OF SIGNIFICANT FLOODING
IS STILL BELOW NORMAL FOR THOSE TWO RIVERS UPSTREAM OF WILLISTON.
..CURRENT DROUGHT CONDITIONS
NO SIGNIFICANT CHANGES HAVE OCCURRED WITH RESPECT TO DROUGHT
DESIGNATIONS OVER THE PAST MONTH. HOWEVER, DROUGHT REMAINS A CONCERN
ACROSS MUCH OF NORTH DAKOTA WITH A LARGE POCKET OF D3 (EXTREME)
DROUGHT CENTERED ON MCKENZIE AND NORTHWEST DUNN COUNTIES. D1 AND D2
LEVELS OF DROUGHT COVER MOST OF THE AREAS WEST OF THE MISSOURI RIVER
AND SOUTH OF I-95 EAST OF HIGHWAY 83. NORTH AND EAST OF THESE AREAS,
DROUGHT DESIGNATIONS RAPIDLY DIMINISH AND ARE NEAR NORMAL.
..RESERVOIRS AND NATURAL WETLANDS
DUE TO THE EARLY MELT OF A VERY UNEVEN, BUT GENERALLY BELOW NORMAL
SNOWPACK THIS YEAR, THE NET RESULTS VARY WILDLY. SOME AREAS HAVE
SEEN ENOUGH RUNOFF TO FILL THE SMALLER NATURAL AND MAN-MADE WATER
FEATURES, BUT OVERALL RUNOFF HAS BEEN LACKING. THIS IS A CAUSE FOR
CONCERN ON SMALLER WATER SUPPLY FEATURES.
..SOIL CONDITIONS
SOIL MOISTURE VALUES REMAIN WELL BELOW NORMAL ACROSS MUCH OF WESTERN
AND SOUTH CENTRAL NORTH DAKOTA. THESE DRY SOILS CONTINUE TO WARM AND
MOST AREAS NOW HAVE LITTLE TO NO FROST IN THE GROUND. THESE WARM AND
DRY SOILS WILL MINIMIZE RUNOFF FROM FUTURE PRECIPITATION.
..WEATHER OUTLOOK
THE NEAR TERM 6-10 DAY WEATHER OUTLOOKS FAVOR ABOVE NORMAL
TEMPERATURES WITH NEAR NORMAL PRECIPITATION EAST OF THE MISSOURI
RIVER, BUT HAS A SLIGHT FAVORING FOR BELOW NORMAL PRECIPITATION IN
THE WESTERN HALF OF THE BASIN. THE SLIGHTLY LONGER TERM 8-14 DAY
OUTLOOKS AGAIN FAVOR ABOVE NORMAL TEMPERATURES, BUT WITH BELOW
NORMAL PRECIPITATION. LOOKING OUT EVEN LONGER, THE ONE-MONTH
OUTLOOKS FOR MAY REFLECT THE EQUAL CHANCES DESIGNATION FOR ABOVE
NORMAL, NEAR NORMAL, OR BELOW NORMAL TEMPERATURES WITH A SLIGHT
FAVORING OF BELOW NORMAL PRECIPITATION. AND FINALLY, IN THE 3-MONTH
OUTLOOKS COVERING MAY, JUNE AND JULY...THE AREA IS AGAIN IN THE
EQUAL CHANCES CATEGORY FOR TEMPERATURE, BUT WITH A SLIGHT FAVORING
FOR BELOW NORMAL PRECIPITATION.
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: 04/26/2025 - 07/25/2025
: 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
-------- ----- ----- ----- : --- --- --- --- --- ---
:PIPESTEM
PINGREE 11.0 13.0 15.0 : <5 <5 <5 <5 <5 <5
:JAMES RIVER
GRACE CITY 12.0 14.0 15.0 : 5 5 <5 <5 <5 <5
LAMOURE 14.0 16.0 18.0 : 8 5 7 <5 <5 <5
:MISSOURI RIVER
WILLISTON 22.0 24.0 26.0 : 5 43 <5 31 <5 14
: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 : 6 38 <5 <5 <5 <5
:BEAVER CREEK
LINTON 12.0 14.0 16.0 : 23 31 12 19 7 12
:LITTLE MUDDY RIVER
WILLISTON 10.0 12.0 14.0 : 16 60 8 31 <5 8
:LITTLE MISSOURI RIVER
MARMARTH 18.0 23.0 30.0 : <5 6 <5 <5 <5 <5
MEDORA 15.0 18.0 20.0 : <5 20 <5 8 <5 6
WATFORD CITY 20.0 24.0 30.0 : <5 10 <5 5 <5 <5
:KNIFE RIVER
MANNING 15.0 17.0 20.0 : <5 17 <5 <5 <5 <5
:SPRING CREEK
ZAP 14.0 18.0 20.0 : 11 19 7 12 6 11
:KNIFE RIVER
HAZEN 21.0 24.0 25.0 : 7 19 <5 16 <5 9
:HEART RIVER
MANDAN 27.0 33.0 38.0 : <5 6 <5 <5 <5 <5
:APPLE CREEK
MENOKEN 15.0 16.0 17.0 : 14 55 6 41 5 19
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: 04/26/2025 - 07/25/2025
LOCATION 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:PIPESTEM
PINGREE 5.7 5.7 5.7 6.5 8.4 10.2 11.0
:JAMES RIVER
GRACE CITY 4.9 4.9 4.9 5.0 7.1 8.2 11.8
LAMOURE 8.0 8.0 8.0 8.0 8.9 10.6 16.9
:MISSOURI RIVER
WILLISTON 17.1 17.3 17.8 18.4 19.1 20.7 22.0
:CANNONBALL RIVER
REGENT 5.2 5.3 6.1 6.8 7.5 8.6 9.7
:CEDAR CREEK
RALEIGH 0.5 1.3 2.2 3.7 4.6 5.2 6.3
:CANNONBALL RIVER
BREIEN 2.5 3.1 4.4 6.1 7.8 9.9 10.7
:BEAVER CREEK
LINTON 4.6 4.8 6.1 8.1 11.7 14.5 16.3
:LITTLE MUDDY RIVER
WILLISTON 4.7 4.7 5.7 8.0 9.3 11.6 12.7
:LITTLE MISSOURI RIVER
MARMARTH 1.0 1.0 1.0 1.7 4.4 9.6 11.8
MEDORA 2.0 2.0 2.0 2.5 6.1 10.3 12.2
WATFORD CITY 7.1 7.1 7.2 8.6 11.0 14.0 15.5
:KNIFE RIVER
MANNING 6.3 6.3 6.5 8.4 9.2 11.4 12.1
:SPRING CREEK
ZAP 4.9 4.9 5.0 6.5 8.0 15.7 21.3
:KNIFE RIVER
HAZEN 1.5 1.5 2.4 4.8 8.0 18.0 23.4
:HEART RIVER
MANDAN 9.4 9.7 10.2 12.1 15.0 20.7 21.9
:APPLE CREEK
MENOKEN 5.7 5.7 5.7 7.9 10.6 15.8 16.8
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: 04/26/2025 - 07/25/2025
LOCATION 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:PIPESTEM
PINGREE 5.4 5.4 5.4 5.3 5.3 5.3 5.3
:JAMES RIVER
GRACE CITY 4.2 4.1 4.0 4.0 4.0 4.0 4.0
LAMOURE 7.9 7.6 7.1 6.8 6.7 6.7 6.7
:MISSOURI RIVER
:CANNONBALL RIVER
REGENT 4.7 4.7 4.7 4.7 4.7 4.7 4.7
:CEDAR CREEK
RALEIGH 0.4 0.3 0.2 0.0 0.0 0.0 0.0
:CANNONBALL RIVER
BREIEN 2.1 2.1 2.1 2.0 2.0 2.0 2.0
:BEAVER CREEK
LINTON 4.5 4.5 4.5 4.4 4.3 4.3 4.3
:LITTLE MUDDY RIVER
WILLISTON 4.6 4.6 4.4 4.3 4.3 4.3 4.3
:LITTLE MISSOURI RIVER
MARMARTH 1.0 1.0 0.9 0.8 0.8 0.8 0.8
MEDORA 2.0 2.0 2.0 2.0 2.0 2.0 2.0
WATFORD CITY 7.1 7.1 7.0 7.0 7.0 7.0 7.0
:KNIFE RIVER
MANNING 6.3 6.3 6.2 6.2 6.1 6.1 6.1
:SPRING CREEK
ZAP 4.9 4.9 4.9 4.8 4.8 4.8 4.8
:KNIFE RIVER
HAZEN 1.4 1.4 1.3 1.2 1.1 1.1 1.1
:HEART RIVER
MANDAN 9.2 9.2 9.2 9.1 9.1 9.0 9.0
:APPLE CREEK
MENOKEN 5.6 5.5 5.4 5.4 5.4 5.4 5.4
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 MAY.
SCHLAG
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