Flood Potential Outlook
Issued by NWS Bismarck, ND
Issued by NWS Bismarck, ND
979
FGUS73 KBIS 301853
ESFBIS
NDC009-013-023-049-069-075-079-101-011900-
Probabilistic Hydrologic Outlook
National Weather Service Bismarck ND
153 PM CDT Thu May 30 2024
This Flood and Water Resources Outlook is for the Souris
River Basin of North Dakota, covering the period of 27 May through
25 August, 2024. This is a monthly issuance of the 90-day flood risks
for the Souris River Basin of North Dakota. These probabilities are
updated on or around, the fourth Thursday of every 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...
Despite several decent sized storm events over the past few weeks,
overall flood risk within the Souris River Basin of North Dakota
remains near normal to below normal.
...Snowpack Conditions...
Despite a recent late offering of snow in and around the Turtle
Mountain area, there is no appreciable snow remain in North Dakota
at this point in time.
...Soil Conditions...
Soil moisture values across the Souris River Basin are mostly
surplus to near normal according to the latest remote sensing
represented in the SPoRT-LIS maps.
...Current Drought Conditions...
Due to recent generous and widespread rainfall, all drought
designations have been removed from the Souris River Basin of North
Dakota. This is a welcome reflection of the improvement seen over
the past few weeks, but keeping drought at bay will require timely
rains over the coming month with growing season hitting its stride.
...Reservoirs and Natural Wetlands...
The majority of natural wetlands and lakes also are at, or near
normal water levels going into spring. Man-made structures, such as
Lake Darling and the upstream Canadian reservoirs of Grant Devine
and Rafferty are faring well given the recent moisture.
...Weather Outlook...
Near term, in the next few days, an above normal expectation for
temperature along with below normal precipitation is favored to
retain the above normal temperature and transition to an equal
chances designation for above normal, near normal, or below normal
precipitation. Looking longer term, the one and three-month outlooks
place the entire state in the equal chances designation for above
normal, near normal, or below normal temperature and precipitation.
This pretty much depicts the Upper Great Plains as an island of
uncertainty whereas the rest of the continental 48 states is
generally favored for above normal temperatures.
...Ice Conditions...
No ice exists along the Souris River and its tributaries
in North Dakota.
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: 05/27/2024 - 08/25/2024
: 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 18 <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 : 14 28 <5 8 <5 <5
Bantry 1440.0 1441.0 1443.0 : 14 31 6 20 <5 <5
:Willow Creek
Willow City 1442.0 1446.0 1448.0 : 10 8 <5 <5 <5 <5
:Souris
Westhope 1414.0 1418.0 1420.0 : 9 27 <5 6 <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: 05/27/2024 - 08/25/2024
Location 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Des Lacs
Foxholm 1639.2 1639.2 1639.2 1640.4 1641.3 1643.1 1643.6
:Souris
Sherwood 1606.4 1606.4 1607.0 1609.2 1611.9 1615.8 1619.2
Foxholm 1566.5 1566.5 1566.5 1567.4 1570.9 1571.3 1572.1
Minot 1550.9 1550.9 1550.9 1551.7 1554.2 1555.1 1555.7
Minot 1541.3 1541.3 1541.3 1541.6 1542.8 1543.3 1543.8
Logan 1520.1 1520.1 1520.4 1523.1 1526.7 1527.8 1529.6
Sawyer 1507.1 1507.1 1507.7 1509.8 1512.2 1513.4 1515.9
Velva 1490.6 1490.6 1491.6 1493.0 1496.3 1498.9 1500.6
:Wintering
Karlsruhe 1504.7 1504.7 1504.7 1504.7 1505.0 1507.7 1508.6
:Souris
Towner 1448.4 1448.4 1448.4 1449.0 1453.0 1454.4 1455.4
Bantry 1434.2 1434.2 1434.2 1434.4 1438.8 1440.4 1441.3
:Willow Creek
Willow City 1438.3 1438.3 1438.3 1438.3 1438.3 1442.1 1445.3
:Souris
Westhope 1411.8 1411.8 1411.8 1411.8 1412.5 1413.5 1415.1
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: 05/27/2024 - 08/25/2024
LOCATION 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Des Lacs
Foxholm 1639.2 1639.1 1638.9 1638.9 1638.8 1638.8 1638.8
:Souris
Sherwood 1606.4 1606.3 1606.1 1605.8 1605.8 1605.8 1605.8
Foxholm 1566.5 1566.5 1566.5 1566.5 1566.5 1566.5 1566.5
Minot 1550.9 1550.9 1550.8 1550.7 1550.6 1550.6 1550.6
Minot 1541.3 1541.3 1541.2 1541.1 1541.1 1541.1 1541.1
Logan 1520.1 1520.0 1520.0 1519.8 1519.8 1519.8 1519.8
Sawyer 1507.0 1506.9 1506.7 1506.6 1506.6 1506.6 1506.6
Velva 1490.4 1490.3 1490.2 1490.2 1490.2 1490.2 1490.2
:Wintering
Karlsruhe 1503.6 1503.3 1503.0 1503.0 1503.0 1503.0 1503.0
:Souris
Towner 1446.5 1446.2 1445.6 1445.2 1445.2 1445.2 1445.2
Bantry 1432.4 1432.1 1431.4 1431.1 1431.0 1431.0 1431.0
:Willow Creek
Willow City 1436.9 1436.8 1436.1 1436.1 1436.1 1436.1 1436.1
:Souris
Westhope 1411.2 1411.0 1410.3 1410.0 1409.9 1409.9 1409.9
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 by the end of June.
$$
Schlag