Flood Potential Outlook Issued by NWS St. Louis, MO
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FGUS73 KLSX 141813
ESFLSX
ILC001-009-013-027-051-149-MOC051-053-071-073-099-111-113-127-
137-151-163-173-183-189-221-291800-
PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE ST. LOUIS MO
110 PM CST Thu Mar 14 2024
...Spring Flood and Water Resources Outlook Number 3...
...Near-normal flood chances along the Illinois River...
...Below-normal flood chances along the Mississippi and Missouri
rivers...
...Below-normal flood chances along most local tributaries...
This outlook uses the term St. Louis Service Area to refer to the
Mississippi River from above Canton, Missouri to below Chester,
Illinois; the Missouri River above Jefferson City, Missouri to its
confluence with the Mississippi River; the Illinois River downstream
from Beardstown, Illinois to its confluence with the Mississippi
River; and for tributaries of these rivers in central and eastern
Missouri and in west central and southwest Illinois.
The probabilities within this outlook are not skewed by any ongoing
flooding nor by any anticipated excessive rainfall.
This outlook is based on current streamflows and soil moisture over
the area; upstream snowpack in the Mississippi, Missouri, and
Illinois river basins; and forecast rainfall over the next two weeks
to three months. More-than-expected rainfall could cause additional
flooding over the area, while less-than-expected rainfall could keep
rivers from reaching the crests considered likely.
The lower Missouri River basin continues to experience widespread
persistent drought. This is particularly true across Iowa,
southeastern Nebraska, and much of northeastern Kansas. This
coupled with low flow along the Missouri and a lack of snow cover
continues to render below-normal flood probabilities from Jefferson
City to St. Charles. The only two locations where minor flooding is
likely this spring through mid-June are at Chamois and at Hermann.
These minor flood probabilities are 22 to 27 percent below
historical norms.
In the Mississippi River basin, the snow water content in the
headwaters is non-existent. Streamflow along the Mississippi River
has fallen back to well-below-normal levels this month, though it is
forecast to rise several feet at St. Louis and at Chester in
response to this week`s convective rainfall. That said, the lack of
snow cover combined with below-normal soil moisture in place from
the Twin Cities to south of St. Louis results in a below-normal risk
of flooding along the Missouri-Illinois stretch of the Mississippi
River. In fact, even minor flooding is unlikely at any forecast
point along the Missouri-Illinois border through mid-June.
There are near- to below-normal flood chances along most local
streams in the St. Louis Service Area over the next 90 days. Over
much of eastern and central Missouri, stream flows have fallen below
the 25th percentile for mid-March, with several locations below the
10th percentile. Similarly low flows are in place across southern
Illinois.
For the St. Louis service area, outlooks from the Climate Prediction
Center indicate a likelihood of near-normal temperatures and near-
to above-normal precipitation for both the next 6-10 day period and
the 8-14 day period. Meanwhile, the outlook for the 3 months from
April through June indicates a slight likelihood for above-normal
temperatures, equal chances of below-, near-, and above-normal
precipitation over most of the service area, and a slight favoring
of above-normal precipitation over southeastern Missouri and
southern Illinois.
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 more 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: 03/18/2024 - 06/16/2024
: 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
Canton 15.0 20.0 25.0 : 19 63 <5 16 <5 <5
LaGrange 17.0 23.0 25.0 : 12 53 <5 10 <5 <5
Quincy 19.0 22.0 26.0 : 14 56 8 28 <5 10
Lock & Dam 21 18.0 21.0 25.0 : 13 55 7 26 <5 10
Hannibal 17.0 22.0 24.0 : 20 61 6 14 <5 10
Saverton 16.0 20.0 24.0 : 24 64 8 39 <5 11
Louisiana 15.0 20.0 25.0 : 37 73 8 33 <5 8
Clarksville 25.0 31.0 33.0 : 37 73 7 28 <5 13
Winfield 26.0 30.0 34.0 : 30 67 8 43 <5 10
Grafton 20.0 24.0 29.0 : 20 67 6 19 <5 6
Mel Price LD 21.0 29.0 34.0 : 37 74 14 21 <5 9
St. Louis 30.0 35.0 40.0 : 28 56 15 34 8 14
Herculaneum 26.0 32.0 37.0 : 36 60 16 36 9 15
Chester 27.0 35.0 40.0 : 46 79 22 41 13 22
:North Fabius River
Ewing 11.0 17.0 20.0 : 49 51 14 15 9 10
:Middle Fabius River
Ewing 12.0 17.0 20.0 : 48 46 13 14 10 10
:South Fabius River
Taylor 10.0 14.0 19.0 : 30 48 12 14 <5 <5
:North River
Palmyra 13.0 16.0 22.0 : 20 26 9 10 <5 <5
:Mid Fork Salt River
Holliday 17.0 22.0 26.0 : 54 54 <5 <5 <5 <5
:Salt River
New London 19.0 25.0 27.0 : <5 <5 <5 <5 <5 <5
:Cuivre River
Troy 21.0 25.0 29.0 : 51 53 20 22 7 8
Old Monroe 24.0 27.0 30.0 : 26 60 14 26 <5 14
:Dardenne Creek
St. Peters 18.0 20.0 23.0 : 36 36 28 28 8 8
:Meramec River
Steelville 12.0 20.0 25.0 : 45 41 <5 <5 <5 <5
Sullivan 11.0 20.0 29.0 : 64 64 12 12 <5 <5
:Bourbeuse River
Union 15.0 22.0 26.0 : 52 50 11 11 <5 <5
:Meramec River
Pacific 15.0 23.0 27.0 : 37 40 7 7 <5 <5
:Big River
Byrnesville 16.0 20.0 28.0 : 42 48 18 20 <5 <5
:Meramec River
Eureka 19.0 26.0 31.0 : 36 41 15 17 7 7
Valley Park 18.0 21.0 27.0 : 44 48 30 37 16 25
Fenton 23.0 29.0 32.0 : 39 50 17 24 12 14
Arnold 24.0 35.0 38.0 : 45 78 21 28 12 22
:Kaskaskia River
Vandalia 18.0 24.0 26.0 : 74 80 31 36 17 19
Carlyle 16.5 23.0 27.0 : 38 76 <5 <5 <5 <5
New Athens 79.0 82.0 85.0 : 36 41 34 34 25 28
:La Moine River
Ripley 22.0 23.0 27.0 : 37 45 33 37 10 11
:Moreau River
Jefferson City 17.0 25.0 29.0 : 62 75 41 50 20 28
:Hinkson Creek
Columbia 15.0 18.0 20.0 : 64 56 58 31 53 9
:Maries River
Westphalia 10.0 15.0 20.0 : 43 44 21 23 <5 <5
:Gasconade River
Rich Fountain 20.0 25.0 30.0 : 28 40 18 25 6 10
:Missouri River
Jefferson City 23.0 25.0 30.0 : 46 69 29 55 16 25
:Osage River
St. Thomas 23.0 30.0 35.0 : 10 17 <5 <5 <5 <5
Mari-Osa Campgrou 19.0 22.0 25.0 : 42 60 22 31 14 22
:Missouri River
Chamois 17.0 28.0 31.0 : 57 79 13 17 <5 10
Hermann 21.0 26.0 33.0 : 54 79 26 47 20 21
Washington 20.0 28.0 31.0 : 46 73 20 21 8 19
St. Charles 25.0 30.0 36.0 : 48 75 22 26 6 14
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: 03/18/2024 - 06/16/2024
Location 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Mississippi River
Canton 6.2 6.8 8.9 11.7 14.3 16.4 18.9
LaGrange 7.1 7.7 9.8 12.6 15.2 17.3 19.8
Quincy 12.2 12.4 12.9 14.8 17.5 19.9 23.1
Lock & Dam 21 6.6 7.5 10.0 13.0 16.3 18.6 21.8
Hannibal 11.0 11.4 12.6 14.6 16.3 18.9 22.3
Saverton 7.3 8.1 9.9 13.2 15.9 19.0 22.7
Louisiana 12.0 12.0 12.1 13.8 16.3 19.1 21.9
Clarksville 17.8 18.4 20.2 23.5 26.7 29.6 32.3
Winfield 17.7 18.3 20.3 23.7 27.0 29.7 32.2
Grafton 15.2 15.4 15.8 16.8 19.7 21.5 24.5
Mel Price LD 9.6 11.0 13.6 20.0 24.4 31.3 32.7
St. Louis 11.8 14.4 18.2 24.9 31.6 39.0 41.0
Herculaneum 9.9 12.5 16.3 22.8 29.3 36.7 38.7
Chester 14.0 16.1 21.6 26.7 33.2 42.8 43.5
:North Fabius River
Ewing 5.8 6.9 8.5 10.9 14.2 19.8 22.3
:Middle Fabius River
Ewing 5.0 6.2 8.5 11.1 15.3 20.0 22.2
:South Fabius River
Taylor 4.9 5.5 6.7 8.8 11.1 14.9 18.3
:North River
Palmyra 5.3 5.5 7.6 8.9 11.6 15.8 18.1
:Mid Fork Salt River
Holliday 10.5 11.7 15.5 17.1 18.9 20.7 21.5
:Salt River
New London 4.8 6.5 9.1 9.4 10.6 12.6 13.4
:Cuivre River
Troy 10.5 11.7 16.1 21.6 24.4 28.4 29.4
Old Monroe 14.2 15.2 17.0 21.0 25.0 27.8 29.0
:Dardenne Creek
St. Peters 7.1 8.5 10.4 15.1 20.7 22.6 23.8
:Meramec River
Steelville 4.1 5.1 6.8 10.9 13.9 16.1 19.6
Sullivan 6.8 7.5 9.2 13.2 16.6 20.6 25.6
:Bourbeuse River
Union 8.0 9.5 11.5 15.1 19.4 22.9 25.6
:Meramec River
Pacific 4.2 6.8 9.9 13.9 17.2 22.1 26.0
:Big River
Byrnesville 7.2 8.4 11.3 14.8 18.4 22.4 25.2
:Meramec River
Eureka 8.6 9.5 13.7 16.3 21.7 28.0 34.9
Valley Park 8.9 9.8 12.3 14.8 24.4 34.4 38.6
Fenton 13.3 15.9 18.1 21.1 26.7 34.1 37.9
Arnold 13.6 15.4 21.3 23.3 31.8 39.0 40.9
:Kaskaskia River
Vandalia 10.4 14.3 16.9 21.9 25.2 27.1 28.5
Carlyle 12.2 12.5 13.9 16.2 19.3 21.1 21.3
New Athens 70.0 70.8 72.4 75.8 85.0 89.6 92.3
:La Moine River
Ripley 11.3 13.3 16.9 19.6 25.3 27.1 28.2
:Missouri River
Jefferson City 10.2 14.0 17.0 21.4 25.1 35.2 35.9
:Osage River
St. Thomas 7.4 10.2 11.8 12.9 15.1 23.1 24.4
Mari-Osa Campgrou 8.3 12.5 13.8 17.5 20.7 27.0 29.9
:Missouri River
Chamois 8.6 11.7 13.5 18.8 22.9 29.0 30.5
Hermann 12.5 15.2 16.9 21.9 26.6 34.3 35.3
Washington 10.3 12.1 13.7 18.9 22.8 30.1 32.7
St. Charles 17.6 19.1 20.3 24.4 27.6 35.1 36.3
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: 03/18/2024 - 06/16/2024
Location 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Mississippi River
Canton 4.7 4.5 4.3 3.5 2.9 2.5 2.1
LaGrange 5.6 5.4 5.2 4.4 3.8 3.4 3.0
Quincy 11.8 11.7 11.7 11.2 10.9 10.9 10.9
Lock & Dam 21 5.2 5.0 4.8 4.1 3.4 3.0 2.6
Hannibal 10.3 10.2 10.1 9.9 9.8 9.6 9.5
Saverton 6.0 5.8 5.6 4.9 4.4 4.0 3.9
Louisiana 11.9 11.9 11.9 11.9 11.8 11.8 11.8
Clarksville 16.1 16.0 15.6 14.5 14.0 13.5 13.2
Winfield 15.9 15.8 15.4 14.4 13.9 13.4 13.0
Grafton 15.0 15.0 14.9 14.8 14.7 14.6 14.5
Alton 19.0 18.8 17.6 15.8 14.3 14.3 14.3
Mel Price LD 5.6 5.6 5.2 4.7 4.1 3.0 2.9
Chester 6.2 5.6 5.0 4.5 4.2 2.3 1.5
:North Fabius River
Ewing 3.6 3.6 3.4 3.2 3.0 2.9 2.8
:Middle Fabius River
Ewing 3.1 3.1 2.9 2.7 2.6 2.5 2.3
:South Fabius River
Taylor 1.9 1.7 1.5 1.5 1.3 1.3 1.0
:North River
Palmyra 3.7 3.6 3.5 3.4 3.1 2.6 2.6
:Mid Fork Salt River
Holliday 4.5 4.4 4.2 4.1 4.0 3.7 3.7
:Salt River
New London 4.8 4.7 4.2 3.4 2.1 1.9 1.9
:Cuivre River
Troy 5.6 5.5 5.3 5.2 5.1 4.9 4.9
Old Monroe 12.1 11.9 11.3 10.1 9.5 9.4 9.3
:Dardenne Creek
St. Peters 1.7 1.6 1.5 1.4 1.3 1.2 1.1
:Meramec River
Steelville 2.3 2.3 2.0 1.8 1.7 1.6 1.5
Sullivan 4.2 4.1 3.7 3.5 3.2 3.2 3.0
:Bourbeuse River
Union 2.5 2.4 2.3 2.2 2.0 1.9 1.8
:Big River
Byrnesville 3.1 2.7 2.5 2.1 1.9 1.7 1.6
:Meramec River
Eureka 4.0 3.8 3.5 3.2 3.0 2.9 2.8
Fenton 3.6 3.5 2.6 2.1 1.8 1.2 1.2
Arnold 7.9 7.7 7.4 7.0 6.7 6.5 6.4
:Kaskaskia River
Vandalia 6.5 4.8 2.9 2.1 1.8 1.5 1.5
Carlyle 10.8 10.3 5.7 5.5 5.5 5.5 5.5
New Athens 69.3 69.0 68.8 68.6 68.5 68.5 68.5
:La Moine River
Ripley 5.9 5.4 5.1 4.8 4.5 4.4 4.3
:Missouri River
Jefferson City 1.2 1.2 1.2 1.2 1.2 1.2 1.2
:Osage River
St. Thomas 3.6 3.1 2.6 2.5 2.5 2.4 2.0
:Missouri River
Hermann 2.2 2.2 2.1 2.1 2.1 2.1 2.1
Washington 0.5 0.4 0.4 0.4 0.4 0.4 0.4
St. Charles 7.2 7.2 7.2 7.2 7.2 7.2 7.1
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/lsx for more weather and water
information.
The next 90-day outlook will be issued on or about the 28th of March.
$$
Fuchs