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Flood Potential Outlook
Issued by NWS Quad Cities, IA IL
Issued by NWS Quad Cities, IA IL
000
FGUS73 KDVN 151903
ESFDVN
IAC011-019-031-045-055-057-061-087-095-097-101-103-105-107-111-113-
115-139-163-177-183-ILC011-015-067-071-073-085-109-131-155-161-177-
187-195-MOC045-199-151800-
Probabilistic Hydrologic Outlook
National Weather Service Quad Cities IA IL
1248 PM CST Thu Feb 15 2024
.2024 Spring Flood and Water Resources Outlook 1...
...Near to Below Normal Flood Risk This Spring...
This is the first update of the three planned Spring Flood and Water
Resource Outlooks for 2024 for the Quad Cities Hydrologic Service
Area (HSA), which covers portions of eastern Iowa, northwest and west
central Illinois, and extreme northeast Missouri. Rivers included in
this outlook are the Mississippi River and its tributaries from above
Dubuque, Iowa to below Gregory Landing, Missouri. The primary
tributary systems include the Maquoketa, Wapsipinicon, Cedar,
English, Iowa, Skunk, North Skunk, and Des Moines Rivers in Iowa; the
Fox River in Missouri; and the Pecatonica, Rock, and Green Rivers in
Illinois, as well as the La Moine River in Illinois. This outlook is
for the time period from late February through late May.
.Flood Outlook Overview...
The spring flood risk is below normal for the Mississippi River, and
near to below Normal for local tributary rivers across the NWS Quad
Cities Hydrologic Service Area.
Some factors contributing to the current risk levels include:
1) Lack of a snowpack in the local area or in the headwater areas in
Minnesota and Wisconsin.
2) Normal to below normal soil moisture levels in the local area will
provide more potential storage for spring rains.
3) Lack of hard frozen soils in the local area or in the headwater
areas to the north.
4) Local streams are currently flowing at or slightly above the
normal level.
.Key Takeaways…
* Even though the overall risk of spring flooding is near to below
average in the NWS Quad Cities HSA, this does not guarantee that high
impact flooding will not occur. The severity of any flooding will be
determined primarily by changes in the key factors mentioned above.
In addition, we will be monitoring the outlooks for spring
precipitation to see if that could become a contributing factor this
year.
* Current snow cover and snow water equivalent are well below normal
across much of the local area, which decreased the overall flood
threat. In addition the snow water equivalent in the headwaters of
the upper Mississippi River basin are well below normal, which will
further decrease our likelihood of major impacts on the Mississippi
River.
* Widespread normal to below normal soil moisture levels in the
local area increases the capacity of the soils to soak in spring
precipitation and which will significantly mitigate the near term
flood risk as well as decrease the risk for prolonged flooding. We
will continue to monitor soil moisture conditions as they have begun
to moisten over the past months.
* A significant snow melt occurred locally at the beginning of
February and caused flood concerns across parts of western Illinois.
This snow melt contributed to moistening the sols and raising river
levels through the Quad Cities’ HSA, which contributes to an increase
in risk along area waterways. If forecasted warmer and drier
conditions persist throughout the rest of February, this will likely
mitigate much of that threat increase, reducing our spring flood
threat further in future outlooks.
Many factors are considered when determining the overall flood risk
for the upcoming spring season. A combination of these are factored
into the final threat categorization. These factors are discussed in
detail below, and are categorized as an increased, neutral, or
decreased contributor to potential spring flooding.
.Seasonal Precipitation:
Local Rivers - Neutral to Decreased Threat
Mississippi River - Neutral to Decreased Threat
Precipitation in eastern Iowa, northwest Illinois and northeast
Missouri has actually averaged around to above normal so far this
winter. However, much of the Hydrologic Service Area (HSA),
especially eastern Iowa, remains in some level of drought due to well
below normal precipitation observed from the fall months in 2023.
This is also well reflected in soil moisture levels (see below).
North of the area, precipitation in the upper Mississippi River Basin
so far this winter has averaged below normal.
Latest outlooks from the Climate Prediction Center favor below normal
precipitation for the remainder of February into April for much, if
not all, of the Mississippi River Basin.
With all of this in mind, any contributions from seasonal
precipitation to spring flood threat will be minimal.
.Snow Cover and Liquid Water Content:
Local Rivers - Decreased to Neutral Threat
Mississippi River - Decreased to Neutral Threat
While snowfall has averaged above normal this winter for much of the
HSA, several prolonged warm spells (where high temperatures have
climbed into the 50s/60s) quickly melted the snowpack. A fast
moving storm system has brought recent snowfall of 2 to 5 inches to
portions of the Upper Mississippi Basin, however much of the
Mississippi River Basin and all of the area tributaries are
completely free of snow cover per the latest analysis from the
National Operational Hydrologic Remote Sensing Center (NOHRSC).
.Soil Conditions:
Local Rivers - Decreased Threat
Mississippi River - Decreased Threat
Despite above normal precipitation values so far this winter, soil
moisture levels remain below normal due to an extremely dry Fall.
Latest analysis from the Climate Prediction Center shows soil
moisture ranking profiles around 10-30% for the majority of the HSA,
and also includes much of the upper Mississippi River Basin. This
favors a decreased to neutral threat from this category for spring
flooding, as drier soils will be better suited to soak in heavier
rains or snow melts.
.Frost Depth:
Local Rivers - Decreased Threat
Mississippi River - Decreased Threat
Little to no frost depth is being observed across eastern Iowa,
northeast Missouri, and west central to northwest Illinois due to
generally above normal temperatures this winter. A week of Arctic
cold did grip the region during the middle of January, but a pre-
existing deep snow cover was able to insulate the ground and prevent
deeper frost depths from occurring. There are some locations with
deeper frozen ground from around 5 to 17 inches in the Upper
Mississippi Basin, but overall frost depths are below normal and will
not contribute to a higher flood risk.
.River Conditions:
Local Rivers - Neutral to Decreased Threat
Mississippi River - Neutral to Decreased Threat
Streamflow analysis from the United States Geological Survey (USGS)
indicates the majority of the Upper Mississippi River watershed
streamflows are near to above normal. The significance of the normal
to above average streamflows to flood risk is that a river with
higher water levels doesn’t have as much capacity to hold higher
amounts of runoff.
.Ice Jam Flooding:
Local Rivers - Decreased Threat for Breakup Jams
Mississippi River - Decreased Threat for Breakup Jams
The warmer weather this winter has largely limited the development of
thick river ice. Although a period of colder temperatures in mid-
January followed by a long duration of above freezing temperatures
did cause some break-up ice jam impacts on the Rock River, all rivers
are free of ice cover heading into mid-February. Colder air will
likely return yet this winter, so ice development and build-up is
still possible. However, without a long period of extreme cold, the
risk for development of thick river ice will be low. This keeps the
risk for spring break-up ice jams low.
.Weather/Climate Outlooks:
Local Rivers - Neutral Threat
Mississippi River - Neutral Threat
While active weather patterns are typical of the spring months, this
could lead to variations of warmer and colder temperatures, where the
risk for flooding will be determined by the tracks of individual and
multiple storm systems that could bring heavy rain or heavy snow to
parts of the region.
According to the latest climate outlooks from the Climate Prediction
Center, probabilities are leaning toward a continuation of above
normal temperatures for much of the region into late February.
Meanwhile, for precipitation into late February there is no strong
signal with equal chances for either above, near or below normal
precipitation.
The three month outlook for March through May is leaning toward a
continuation of above normal temperatures for much of the region,
with equal chances for either above, near or below normal
precipitation.
.Summary:
The spring flood risk is below normal for the Mississippi River, and
near to below normal for local tributary rivers across the NWS Quad
Cities Hydrologic Service Area. The flood risk will be assessed 2
more times this spring.
Current snow cover and snow water equivalent is significantly lower
than average in both the local area and the headwater areas of the
Mississippi basin. Large snow events in the local area led to a large
snowpack during January, but warm temperatures in late January and
early February led to a snowmelt that moistened soils and runoff.
Snow runoff and ice break up led to some minor flooding in western
Illinois, leaving current conditions unfavorable for snowmelt or ice
jam flooding on local tributaries.
Some factors contributing to the current risk levels include: 1) Lack
of deep and widespread snowpack in the local area and the headwater
areas of the Mississippi River basin. 2) A general lack of deep, hard
frozen ground across the upper Mississippi River Basin. 3) Near to
above average stream flows and near to slightly below average soil
moisture levels .
.Numerical Probabilistic River Outlooks...
This outlook provides long-range probabilistic river outlooks for
river basins in the NWS Quad Cities service area. This outlook is
divided into three parts, the first part for the probabilities of
minor, moderate and major flooding, the second part for high water
and the final part for low water.
In Table 1 below, the current (CS) and historical (HS) or normal
probabilities of exceeding minor, moderate and major flood stages
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: 02/19/2024 - 05/19/2024
: 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
-------- ----- ----- ----- : --- --- --- --- --- ---
:Mississippi River
Dubuque LD11 16.0 17.0 20.5 : 20 48 16 38 <5 12
Dubuque 17.0 18.0 21.5 : 22 53 20 45 <5 15
Bellevue LD12 17.0 18.0 20.0 : 14 37 11 32 <5 12
Fulton LD13 16.0 18.0 20.0 : 21 53 13 35 <5 14
Camanche 17.0 18.5 20.5 : 20 44 13 35 <5 14
Le Claire LD14 11.0 12.0 13.5 : 20 51 15 37 9 18
Rock Island LD15 15.0 16.0 18.0 : 30 59 20 50 12 27
Ill. City LD16 15.0 16.0 18.0 : 27 56 20 48 13 25
Muscatine 16.0 18.0 20.0 : 33 59 20 48 13 25
New Boston LD17 15.0 16.5 18.5 : 38 61 21 50 15 31
Keithsburg 14.0 15.5 17.0 : 37 62 23 50 12 28
Gladstone LD18 10.0 12.0 14.0 : 37 63 19 47 11 24
Burlington 15.0 16.5 18.0 : 36 61 19 48 11 28
Keokuk LD19 16.0 17.5 19.0 : 14 32 11 21 7 12
Gregory Landing 15.0 18.0 25.0 : 41 63 16 42 <5 <5
:Maquoketa River
Manchester Hwy 20 14.0 17.0 20.0 : 16 22 8 15 <5 6
Maquoketa 24.0 26.0 28.5 : 5 19 <5 16 <5 6
:Wapsipinicon River
Independence 12.0 13.0 15.0 : 5 7 <5 6 <5 <5
Anamosa Shaw Rd 14.5 18.0 21.5 : 15 24 8 12 <5 <5
De Witt 4S 11.0 11.5 12.5 : 68 71 59 65 28 43
:North Skunk River
Sigourney 16.0 18.0 21.0 : 44 57 28 41 7 13
:Skunk River
Augusta 15.0 17.0 20.0 : 40 41 23 28 8 14
:Cedar River
Vinton 15.0 18.0 19.0 : <5 16 <5 5 <5 <5
Palo Blairs Ferry 12.5 15.5 17.0 : 5 27 <5 5 <5 <5
Cedar Rapids 12.0 14.0 16.0 : 6 33 <5 15 <5 8
Cedar Bluff 16.0 20.0 26.0 : 6 32 <5 8 <5 <5
Conesville 13.0 15.0 16.5 : 24 55 <5 15 <5 6
:Iowa River
Marengo 15.0 17.0 19.0 : 39 71 21 45 <5 6
Iowa City 23.5 24.5 26.0 : <5 <5 <5 <5 <5 <5
Lone Tree 16.0 18.5 22.0 : 23 33 5 7 <5 <5
Columbus Jct 23.0 25.0 26.5 : 6 18 <5 6 <5 <5
Wapello 21.0 25.0 27.5 : 24 53 <5 7 <5 <5
Oakville 11.0 15.0 20.0 : 13 34 <5 <5 <5 <5
:English River
Kalona 14.0 16.0 18.0 : 45 55 22 33 10 15
:Des Moines River
Keosauqua 22.0 25.0 27.0 : 6 10 <5 <5 <5 <5
St Francisville 18.0 22.0 25.0 : 20 36 6 7 <5 <5
:Fox River
Wayland 15.0 18.0 20.0 : 23 22 9 10 <5 <5
:Pecatonica River
Freeport 13.0 14.0 16.0 : 11 21 <5 10 <5 <5
:Rock River
Como 12.5 15.5 18.0 : 14 25 <5 11 <5 <5
Joslin 12.0 14.0 16.5 : 60 56 28 33 8 19
Moline 12.0 13.0 14.0 : 54 53 28 32 17 26
:Green River
Geneseo 15.0 16.5 18.0 : 22 27 11 13 <5 <5
:La Moine River
Colmar 20.0 22.0 24.0 : 67 63 46 44 22 18
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: 02/19/2024 - 05/19/2024
Location 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Mississippi River
Dubuque LD11 7.2 8.1 9.7 11.7 14.8 19.0 19.6
Dubuque 9.6 10.3 11.6 13.6 16.7 20.7 21.3
Bellevue LD12 8.1 9.0 10.4 12.3 15.0 18.5 19.1
Fulton LD13 7.8 8.6 10.3 12.1 15.1 19.2 19.9
Camanche 10.4 11.0 12.2 13.3 15.7 19.7 20.5
Le Claire LD14 6.3 6.7 7.8 8.9 10.4 13.4 14.2
Rock Island LD15 8.7 9.4 11.0 12.3 15.3 18.3 19.4
Ill. City LD16 7.2 8.1 10.1 12.0 15.1 18.1 19.6
Muscatine 8.9 9.9 11.7 13.5 16.8 20.1 21.3
New Boston LD17 8.7 9.7 11.7 13.4 16.1 19.3 20.6
Keithsburg 9.4 9.9 11.5 12.7 15.0 18.0 18.7
Gladstone LD18 4.6 5.2 7.3 8.8 11.2 14.6 15.5
Burlington 10.5 10.9 12.5 13.8 15.8 18.8 19.7
Keokuk LD19 6.5 7.4 9.3 10.8 13.9 18.0 19.5
Gregory Landing 8.0 9.0 11.6 13.8 16.6 20.2 22.3
:Maquoketa River
Manchester Hwy 20 5.9 6.3 7.3 8.4 10.7 16.3 19.3
Maquoketa 11.8 12.6 13.7 15.5 17.9 22.5 25.2
:Wapsipinicon River
Independence 5.4 5.6 6.4 7.2 8.2 10.7 12.6
Anamosa Shaw Rd 6.0 7.4 8.5 10.3 12.3 16.7 18.9
De Witt 4S 8.6 9.4 10.4 11.7 12.7 13.3 13.6
:North Skunk River
Sigourney 5.5 9.6 13.2 15.4 19.1 20.2 22.0
:Skunk River
Augusta 4.7 5.8 9.1 12.7 16.2 19.1 23.3
:Cedar River
Vinton 3.5 4.2 6.2 8.8 11.4 13.3 14.7
Palo Blairs Ferry 3.3 4.1 5.8 8.0 10.3 11.7 12.9
Cedar Rapids 3.7 4.1 4.9 6.5 9.2 11.3 13.4
Cedar Bluff 5.8 6.3 8.2 10.1 12.9 14.9 17.6
Conesville 7.0 7.5 9.3 10.7 12.8 13.9 14.8
:Iowa River
Marengo 7.3 8.8 10.9 13.4 16.7 18.0 18.4
Iowa City 10.3 11.5 13.3 15.2 19.0 19.7 20.4
Lone Tree 6.2 8.3 10.4 12.6 15.4 17.7 18.6
Columbus Jct 10.7 12.6 14.1 16.0 18.7 22.1 23.1
Wapello 13.2 15.2 16.8 18.3 20.5 22.8 23.8
Oakville 2.3 3.8 5.3 6.8 9.1 11.6 12.6
:English River
Kalona 7.1 8.2 12.3 13.6 15.8 18.0 19.6
:Des Moines River
Keosauqua 11.5 14.0 16.1 17.9 19.1 20.9 22.9
St Francisville 8.3 11.5 13.9 15.8 17.6 20.1 23.5
:Fox River
Wayland 5.2 5.7 8.9 11.7 14.4 17.8 19.0
:Pecatonica River
Freeport 7.0 7.8 8.6 10.8 12.2 13.0 13.7
:Rock River
Como 6.4 6.7 7.5 9.7 11.3 12.9 15.1
Joslin 9.1 9.7 10.5 12.6 14.4 16.0 18.8
Moline 9.9 10.3 11.0 12.2 13.6 14.5 17.7
:Green River
Geneseo 6.2 6.8 10.1 12.0 14.7 16.7 18.0
:La Moine River
Colmar 10.3 13.1 17.9 21.6 23.8 25.2 26.3
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: 02/19/2024 - 05/19/2024
Location 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Mississippi River
Dubuque LD11 5.7 5.6 5.3 4.9 4.7 4.5 4.3
Dubuque 8.3 8.2 8.0 7.8 7.7 7.5 7.4
Bellevue LD12 5.8 5.7 5.2 4.7 4.3 4.1 3.8
Fulton LD13 5.6 5.5 5.1 4.8 4.7 4.6 4.4
Camanche 9.3 9.3 9.1 9.0 8.8 8.8 8.7
Le Claire LD14 5.1 5.1 4.9 4.8 4.7 4.6 4.5
Rock Island LD15 6.3 6.1 5.9 5.5 5.1 4.8 4.4
Ill. City LD16 5.0 4.9 4.8 4.5 4.2 3.9 3.5
Muscatine 7.0 6.9 6.8 6.6 6.4 6.2 6.0
New Boston LD17 5.8 5.5 5.4 4.8 4.3 3.9 3.5
Keithsburg 6.9 6.8 6.8 6.3 6.0 5.8 5.5
Gladstone LD18 2.6 2.5 2.4 2.0 1.7 1.4 1.1
Burlington 8.6 8.5 8.5 8.3 8.1 7.9 7.6
Keokuk LD19 4.9 4.8 4.7 4.3 3.7 3.0 2.4
Gregory Landing 6.8 6.7 6.7 6.6 6.5 6.3 6.3
:Maquoketa River
Manchester Hwy 20 4.2 4.1 4.1 4.0 4.0 3.9 3.9
Maquoketa 11.0 10.9 10.8 10.6 10.4 10.2 10.1
:Wapsipinicon River
Independence 5.0 5.0 4.9 4.8 4.8 4.7 4.7
Anamosa Shaw Rd 5.3 5.3 5.1 5.0 4.9 4.7 4.7
De Witt 4S 7.1 6.9 6.7 6.5 6.1 5.8 5.7
:North Skunk River
Sigourney 4.6 4.4 4.2 3.9 3.7 3.4 3.2
:Skunk River
Augusta 2.7 2.5 2.4 1.9 1.7 1.3 1.2
:Cedar River
Vinton 1.9 1.8 1.7 1.6 1.5 1.4 1.4
Palo Blairs Ferry 1.9 1.8 1.7 1.6 1.5 1.5 1.4
Cedar Rapids 3.0 2.9 2.9 2.8 2.8 2.7 2.7
Cedar Bluff 4.4 4.2 4.1 4.0 3.9 3.8 3.7
Conesville 5.5 5.3 5.2 5.1 4.9 4.7 4.6
:Iowa River
Marengo 6.4 6.3 6.2 6.0 5.8 5.7 5.6
Iowa City 9.8 9.7 9.6 9.3 9.2 9.1 9.1
Lone Tree 5.1 4.9 4.8 4.4 4.1 3.8 3.7
Columbus Jct 9.5 9.3 9.1 8.9 8.6 8.4 8.3
Wapello 11.9 11.7 11.5 11.2 10.7 10.5 10.1
Oakville 1.3 1.2 1.0
0.7 0.3 0.1 0.0
:English River
Kalona 4.7 4.6 4.4 4.2 3.9 3.7 3.6
:Des Moines River
Keosauqua 10.7 10.5 10.3 10.1 9.9 9.8 9.7
St Francisville 6.9 6.6 6.3 5.9 5.7 5.4 5.3
:Fox River
Wayland 2.4 2.3 2.0 2.0 1.9 1.7 1.6
:Pecatonica River
Freeport 6.4 6.1 5.6 5.1 4.6 4.2 4.1
:Rock River
Como 5.5 5.3 5.0 4.5 3.9 3.5 3.3
Joslin 7.8 7.6 7.2 6.5 5.7 5.2 4.9
Moline 9.3 9.2 9.0 8.7 8.3 8.2 8.0
:Green River
Geneseo 3.6 3.5 3.4 3.1 2.7 2.4 2.3
:La Moine River
Colmar 5.2 5.0 4.8 4.2 3.9 3.6 3.5
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 at http://www.weather.gov/dvn for more weather and
water information.
The next outlook will be issued on 29 February 2024.
$$
- National Weather Service
- Louisville, KY Weather Forecast Office
- 6201 Theiler Lane
- Louisville, KY 40229-1476
- 502-969-8842
- Page Author: LMK Webmaster
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- Page last modified: Sep 19th, 2023 19:10 UTC