Flood Potential Outlook
Issued by NWS Bismarck, ND
Issued by NWS Bismarck, ND
847
FGUS73 KBIS 301828
ESFBIS
NDC001-007-011-015-021-025-029-031-033-037-041-043-045-047-051-053-
055-057-059-061-065-083-085-087-089-093-103-105-011830-
Probabilistic Hydrologic Outlook
National Weather Service Bismarck ND
128 PM CDT Thu May 30 2024
...FLOOD AND WATER RESOURCES OUTLOOK...
This Flood and Water Resources Outlook is for the James and
Missouri basins of North Dakota, covering the period of 25 May
through 23 August, 2024. This is a routine monthly issuance of flood
probabilities for NWS forecast locations. These probabilities are
issued 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 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...
Coming into spring, the largest concern was generally the lack of
snow and early spring rains. The month of May has been a welcome
reprieve from the drought concerns, and all without any substantial
flooding. These rains in May have alleviated soil moisture deficits
and removed drought across all but the very southwestern corner of
North Dakota. Despite the frequent rains, the prospects of
widespread flooding remain below normal to near normal for this time
of year. Nonetheless, as many long-term residents are keenly aware,
this time of year...North Dakota always seems to be only a week or
so away from either a drought or flood. This makes a continuation of
the recent abundant moisture critical in determining how the summer
goes.
...Missouri and Yellowstone Rivers...
Recent moisture, both on the plains of eastern Montana and in the
headwaters area have been above normal. This is welcome news given
the near record low snowpack coming out of winter. Especially over
the past few weeks, runoff and snowpack in the Rockies has helped
both the Missouri and Yellowstone rivers from reaching the low water
levels expected earlier on. Concerns still remain as overall runoff
for the year is still expected to be below normal, but perhaps not
as much below normal as expected just a couple months ago.
...Snowpack Conditions...
No snowpack exists within either the Missouri or James River basins
of North Dakota.
...Current Drought Conditions...
Timely and abundant rainfall across North Dakota has removed drought
designations from all but the very southwestern corner of the state.
Nonetheless, with the region well into the growing season now, a
continuation of the timely rains will be needed to keep drought
concerns at bay going into what is the warmest time of the year.
...Reservoirs and Natural Wetlands...
Streamflow, natural wetlands and small water features generally have
normal to above normal water levels for this time of year.
...Soil Conditions...
Soil moisture values have trended upwards over the past few weeks.
SpoRT-LIS remote sensing of soil moisture now shows roughly
three-fourths of the state with above normal soil moisture, with the
remainder having near normal soil moisture values. This is a
remarkable turnaround from having large areas with below normal soil
moisture just last month.
...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 is known to exist on any river or stream 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: 05/25/2024 - 08/23/2024
: 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
-------- ----- ----- ----- : --- --- --- --- --- ---
: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 5 <5 <5 <5
:Missouri River
Williston 22.0 24.0 26.0 : 8 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 : 15 40 <5 <5 <5 <5
:Beaver Creek
Linton 12.0 14.0 16.0 : 10 28 8 13 6 11
:Little Muddy River
Williston 10.0 12.0 14.0 : 12 57 6 29 <5 5
:Little Missouri River
Marmarth 18.0 23.0 30.0 : <5 6 <5 <5 <5 <5
Medora 15.0 18.0 20.0 : <5 13 <5 6 <5 5
Watford City 20.0 24.0 30.0 : <5 6 <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 : 6 15 5 12 <5 11
:Knife River
Hazen 21.0 24.0 25.0 : 10 18 <5 16 <5 9
:Heart River
Mandan 27.0 33.0 38.0 : 5 9 <5 <5 <5 <5
:Apple Creek
Menoken 15.0 16.0 17.0 : 31 46 14 35 6 9
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: 05/25/2024 - 08/23/2024
Location 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Pipestem
Pingree 5.4 5.4 5.4 5.5 7.9 10.0 10.8
:James River
Grace City 4.8 4.8 4.8 5.0 6.8 9.0 11.8
LaMoure 8.1 8.1 8.1 8.1 9.0 12.4 16.4
:Missouri River
Williston 19.4 19.6 20.0 20.4 21.0 21.8 23.7
:Cannonball River
Regent 5.4 5.4 5.4 6.6 7.0 7.8 9.1
:Cedar Creek
Raleigh 1.3 1.3 2.6 4.1 5.1 6.4 7.0
:Cannonball River
Breien 2.5 3.0 4.6 7.0 8.4 10.4 11.4
:Beaver Creek
Linton 5.0 5.0 5.2 6.7 9.8 12.1 16.6
:Little Muddy River
Williston 4.7 4.7 4.9 5.9 7.2 11.1 12.1
:Little Missouri River
Marmarth 1.1 1.1 1.1 1.2 2.6 6.0 6.8
Medora 1.7 1.7 1.7 1.8 3.3 6.1 7.1
Watford City 7.6 7.6 7.6 8.2 9.6 11.0 12.6
:Knife River
Manning 6.3 6.3 6.4 7.1 9.3 11.4 13.1
:Spring Creek
Zap 5.0 5.0 5.0 5.3 8.0 9.9 18.1
:Knife River
Hazen 1.1 1.1 1.2 3.9 9.0 21.5 23.7
:Heart River
Mandan 10.0 10.1 11.1 13.8 16.7 21.8 27.5
:Apple Creek
Menoken 5.1 5.1 5.4 11.4 15.1 16.7 18.0
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: 05/25/2024 - 08/23/2024
LOCATION 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Pipestem
Pingree 5.1 5.0 5.0 4.9 4.8 4.8 4.8
:James River
Grace City 4.6 4.6 4.6 4.5 4.5 4.5 4.5
LaMoure 7.9 7.8 7.6 7.5 7.4 7.4 7.4
:Missouri River
:Cannonball River
Regent 5.3 5.2 5.2 5.2 5.2 5.2 5.2
:Cedar Creek
Raleigh 1.2 1.1 1.1 1.1 1.0 1.0 0.9
:Cannonball River
Breien 2.4 2.3 2.2 2.2 2.1 2.1 2.1
:Beaver Creek
Linton 4.6 4.5 4.5 4.4 4.3 4.3 4.3
:Little Muddy River
Williston 4.7 4.7 4.7 4.7 4.7 4.7 4.7
:Little Missouri River
Marmarth 1.1 1.1 1.0 1.0 0.9 0.9 0.9
Medora 1.4 1.4 1.3 1.3 1.2 1.2 1.2
Watford City 7.1 7.1 7.0 6.9 6.9 6.8 6.8
:Knife River
Manning 6.2 6.2 6.2 6.0 6.0 6.0 6.0
:Spring Creek
Zap 5.0 5.0 5.0 4.9 4.9 4.9 4.9
:Knife River
Hazen 1.1 1.1 1.1 1.0 1.0 1.0 1.0
:Heart River
Mandan 9.9 9.8 9.7 9.6 9.6 9.6 9.5
:Apple Creek
Menoken 4.4 4.2 4.0 3.7 3.4 3.3 3.3
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