293
FGUS73 KBIS 261802
ESFBIS
NDC009-013-023-049-069-075-079-101-281815-
PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE BISMARCK ND
1202 PM CST THU JAN 26 2023
..FLOOD AND WATER RESOURCES OUTLOOK
THIS FLOOD AND WATER RESOURCES OUTLOOK IS FOR THE SOURIS RIVER BASIN
OF NORTH DAKOTA, COVERING THE PERIOD OF 30 JANUARY THROUGH 30 APRIL,
2023. THIS OUTLOOK IS A ROUTINE RELEASE OF THE MONTHLY PROBABILITIES
FOR FLOODING OVER THE NEXT 90 DAYS. THESE PROBABILITIES ARE UPDATED
ON, OR NEAR, THE FOURTH THURSDAY OF EACH MONTH.
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
NORMAL/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
THE EARLY 30-60 DAYS OF THIS OUTLOOK,
COVERING FEBRUARY AND MARCH, ARE TRADITIONALLY QUIET WITH RESPECT TO
FLOODING, BUT THE LAST 30 DAYS OF THIS OUTLOOK COVERS LATE MARCH
THROUGH APRIL, WHICH INCLUDES MUCH OF THE TRADITIONAL SPRING MELT
SEASON. THEREFORE, THE PROBABILITIES ASSIGNED TO FLOOD RISK SHOULD
BE CONSIDERED PRIMARILY ASSOCIATED WITH LATE MARCH AND EARLY APRIL.
OVERALL, THE FLOOD RISK WITHIN THE SOURIS RIVER BASIN OF NORTH
DAKOTA ARE A MIX OF SLIGHTLY BELOW NORMAL TO SLIGHTLY ABOVE NORMAL
PROBABILITIES. FLOOD RISK IS BELOW NORMAL NEAR SHERWOOD WHERE THE
SOURIS RIVER FLOWS INTO NORTH DAKOTA. HOWEVER, FLOOD RISK STEADILY
INCREASES TO NEAR NORMAL IN THE MINOT AREA AND CONTINUES TO INCREASE
TO SLIGHTLY ABOVE NORMAL AS ONE NEARS THE TOWNER AND BANTRY GAGES ON
THE SOURIS RIVER. OTHER FORECAST POINTS, INCLUDING THE WINTERING
RIVER NEAR KARLSRUHE AND WILLOW CREEK NEAR WILLOW CITY ARE ALSO NEAR
NORMAL TO SLIGHTLY ABOVE NORMAL. THE PATTERN OF RISK REFLECTS THE
SNOW-WATER EQUIVALENT (SWE) OF THE LOCAL SNOWPACK. ONE OF THE
IMPORTANT CONSIDERATIONS IN DETERMINING FLOOD RISK ARE SOIL
CONDITIONS. THE SOIL BENEATH THE SNOWPACK IS WIDELY CONSIDERED
EXCEPTIONALLY DRY AND GENERALLY WARMER THAN NORMAL. THE WARM AND DRY
SOILS UNDERNEATH THE SNOWPACK WILL ALLOW INFILTRATION OF MELTWATER
AND SUBSTANTIALLY REDUCE RUNOFF DURING ALL BUT AN EXTREME MELT
PATTERN THIS SPRING. THIS SUGGESTS THAT THE ALWAYS IMPORTANT MELT
PATTERN WILL BE EVEN MORE CRITICAL THIS YEAR IN DETERMINING THE
FRACTION OF MELTWATER THAT WILL INFILTRATE INTO THE SOIL, AND HOW
MUCH WILL TURN INTO RUNOFF AND FIND ITS WAY INTO LOCAL RIVERS AND
STREAMS.
ALL THAT BEING SAID, ONE SHOULD REMEMBER THAT THE REGION IS ROUGHLY
HALFWAY THROUGH THE SNOW ACCUMULATION SEASON AND OVERALL SWE CONTENT
CAN SIGNIFICANTLY CHANGE DURING THE MONTHS OF FEBRUARY AND MARCH.
BECAUSE FLOOD RISK CAN EVOLVE RATHER QUICKLY OVER THE COMING WEEKS,
THESE FLOOD RISKS WILL BE UPDATED ON FEBRUARY 9TH, 2023 AS A PART OF
THE SPRING FLOOD AND WATER RESOURCES OUTLOOKS, AND EVERY TWO WEEKS
THEREAFTER UNTIL WE ARE BACK ON TRACK WITH THE NORMAL MONTHLY
RELEASE OF THESE PROBABILITIES ON THE FOURTH THURSDAY OF MARCH.
..SNOWPACK CONDITIONS
SNOWPACK ACROSS THE SOURIS RIVER BASIN IS NOT VERY UNIFORM. IN
GENERAL, THE HEADWATERS AREA OF SASKATCHEWAN IS BELOW TO NEAR NORMAL
IN SWE WITH AN OVERALL VALUE OF SOMETHING LESS THAN TWO INCHES.
SNOWPACK AND SWE CONTENT TENDS TO INCREASE TO NEAR NORMAL WHERE THE
SOURIS RIVER FLOWS INTO NORTH DAKOTA NEAR SHERWOOD, AND CONTINUES TO
INCREASE THE FARTHER DOWNSTREAM ONE LOOKS UNTIL IT IS GENERALLY
ABOVE NORMAL EAST OF MINOT WHERE FOUR INCHES OF SWE IS BELIEVED TO
EXIST IN LOCALIZED AREAS.
..CURRENT DROUGHT CONDITIONS
DESPITE A NEAR NORMAL SNOWPACK IN THE UPPER PORTION OF THE SOURIS
RIVER BASIN OF NORTH DAKOTA AND ABOVE NORMAL SWE CONTENT IN THE
EASTERN AND SOUTHERN PART OF THE BASIN, THE BASIN WIDE MODERATE
DROUGHT (D1) DESIGNATION HAS HELD STEADY THIS WINTER. DEPENDING ON
HOW THE SPRING MELT UNFOLDS, IT IS POSSIBLE WE WILL SEE RAPID
IMPROVEMENT IN THE DROUGHT DESIGNATIONS IN RESPONSE TO ADEQUATE
STREAMFLOW AND SUBSTANTIAL REPLENISHMENT OF SOIL MOISTURE.
..RESERVOIRS AND NATURAL WETLANDS
LAKE DARLING ABOVE MINOT ALONG WITH THE CANADIAN RESERVOIRS BEHIND
GRANT DEVINE AND RAFFERTY DAMS HAVE NEAR NORMAL TO SOMEWHAT BELOW
NORMAL WATER LEVELS FOR THIS TIME OF YEAR. THE SAME CAN BE SAID FOR
MOST WETLANDS AND NATURAL BODIES OF WATER AS THE DRIER THAN NORMAL
LATTER HALF OF SUMMER AND EARLY FALL TOOK A TOLL ON WATER LEVELS IN
2022.
..SOIL CONDITIONS
SOILS ACROSS THE BASIN ARE QUITE DRY. ALONG WITH THE SOILS BEING
DRY, THE INSULATING EFFECT OF THE EARLY SNOW HAS KEPT THE SOILS
UNDER THE SNOW WARMER THAN ONE WOULD EXPECT BASED ON THE RECENT COLD
WEATHER. THIS WILL HELP THE SOILS MINIMIZE RUNOFF FROM MELTWATER
GENERATED UNDER ALL BUT THE MOST EXTREME OF MELT CONDITIONS.
..WEATHER OUTLOOK
AS WE NEAR THE END OF JANUARY, THE 6-10, 8-14, AND WEEKS 3-4
OUTLOOKS ALL STRONGLY FAVOR COOLER THAN NORMAL TEMPERATURES WHILE
SLIGHTLY FAVORING BELOW NORMAL PRECIPITATION. THE 3-MONTH OUTLOOKS,
COVERING FEBRUARY, MARCH AND APRIL, ALSO FAVOR BELOW NORMAL
TEMPERATURES WITH A SLIGHT FAVORING OF ABOVE NORMAL PRECIPITATION. A
COOLER THAN NORMAL PATTERN SUGGESTS THE REGION MAY SEE A SOMEWHAT
LATER THAN NORMAL SPRING MELT SEASON AND SHOULD HELP ENSURE EXISTING
AND FUTURE SWE WILL BE RESERVED FOR THE SPRING MELT SEASON. THIS
WOULD BE CONSISTENT WITH THE EXPECTATION THAT THE REGION WILL GO
INTO THE SPRING MELT SEASON WITH A NEAR NORMAL TO SOMEWHAT ABOVE
NORMAL SWE CONTENT IN THE SNOWPACK.
..ICE CONDITIONS
ALL SMALL LAKES AND WETLANDS ARE COVERED WITH ICE NOW OF VARIABLE
THICKNESS. LAKES WITH SUBSTANTIAL SNOW COVER ARE LIKELY TO HAVE
THINNER ICE DUE TO THE INSULATING EFFECT OF THE DEEPER SNOW.
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: 01/30/2023 - 04/30/2023
: 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 10 <5 5 <5 <5
FOXHOLM 1573.0 1576.0 1578.0 : 30 28 8 12 <5 <5
MINOT 1562.0 1565.0 1570.0 : 10 13 8 6 <5 <5
MINOT 1551.0 1553.0 1557.0 : 7 <5 <5 <5 <5 <5
LOGAN 1536.0 1538.0 1540.0 : 21 16 7 <5 <5 <5
SAWYER 1524.0 1526.0 1528.0 : 8 7 <5 <5 <5 <5
VELVA 1507.0 1512.0 1517.0 : 15 13 <5 <5 <5 <5
:WINTERING
KARLSRUHE 1509.0 1511.0 1512.0 : 27 13 <5 <5 <5 <5
:SOURIS
TOWNER 1454.0 1456.0 1458.0 : 77 51 37 21 <5 <5
BANTRY 1440.0 1441.0 1443.0 : 78 51 62 35 6 8
:WILLOW CREEK
WILLOW CITY 1442.0 1446.0 1448.0 : 46 46 7 19 <5 <5
:SOURIS
WESTHOPE 1414.0 1418.0 1420.0 : 26 47 <5 18 <5 16
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: 01/30/2023 - 04/30/2023
LOCATION 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:DES LACS
FOXHOLM 1641.4 1641.8 1642.6 1643.7 1646.6 1648.3 1650.8
:SOURIS
SHERWOOD 1610.6 1611.2 1612.6 1615.9 1619.8 1621.2 1622.4
FOXHOLM 1570.4 1570.5 1570.8 1571.0 1573.1 1575.7 1576.7
MINOT 1554.1 1554.5 1554.8 1556.3 1559.3 1562.0 1566.2
MINOT 1542.8 1543.1 1543.3 1544.0 1545.3 1547.4 1551.5
LOGAN 1526.6 1527.4 1527.9 1530.1 1535.0 1537.1 1538.2
SAWYER 1512.1 1513.0 1513.6 1516.5 1520.7 1523.1 1525.1
VELVA 1496.1 1497.0 1497.9 1502.0 1506.0 1507.8 1509.4
:WINTERING
KARLSRUHE 1505.8 1506.1 1507.2 1508.4 1509.0 1509.6 1510.0
:SOURIS
TOWNER 1452.9 1453.3 1454.1 1455.5 1456.5 1457.1 1457.6
BANTRY 1438.8 1439.2 1440.1 1441.4 1442.1 1442.6 1443.1
:WILLOW CREEK
WILLOW CITY 1437.8 1438.0 1438.7 1441.0 1444.2 1445.2 1446.6
:SOURIS
WESTHOPE 1411.5 1411.7 1412.3 1413.4 1414.1 1416.2 1417.4
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: 01/30/2023 - 04/30/2023
LOCATION 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:DES LACS
FOXHOLM 1638.7 1638.6 1638.6 1638.6 1638.6 1638.6 1638.6
:SOURIS
SHERWOOD 1606.3 1606.3 1606.2 1606.2 1606.2 1606.2 1606.2
FOXHOLM 1566.8 1566.8 1566.5 1566.5 1566.5 1566.5 1566.5
MINOT 1551.0 1550.9 1550.8 1550.8 1550.6 1550.6 1550.6
MINOT 1541.4 1541.3 1541.2 1541.2 1541.1 1541.1 1541.1
LOGAN 1520.5 1520.2 1520.0 1519.9 1519.9 1519.8 1519.8
SAWYER 1507.7 1507.4 1506.7 1506.7 1506.7 1506.6 1506.6
VELVA 1491.2 1490.9 1490.2 1490.2 1490.2 1490.2 1490.2
:WINTERING
KARLSRUHE 1503.0 1503.0 1503.0 1503.0 1503.0 1503.0 1503.0
:SOURIS
TOWNER 1444.4 1444.4 1444.4 1444.4 1444.4 1444.4 1444.4
BANTRY 1430.3 1430.3 1430.2 1430.2 1430.2 1430.2 1430.2
:WILLOW CREEK
WILLOW CITY 1436.1 1436.1 1436.1 1436.1 1436.1 1436.1 1436.1
:SOURIS
WESTHOPE 1409.8 1409.5 1409.2 1409.0 1408.9 1408.9 1408.9
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 9 FEBRUARY, 2023.
SCHLAG
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