Flood Potential Outlook
Issued by NWS St. Louis, MO

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Probabalistic Hydrologic Outlook
National Weather Service St Louis MO
459 PM CDT Thu Oct 31 2024

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:  10/28/2024 - 01/26/2025

                                          :    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
--------               -----  ----  ----- : ---  ---  ---  ---  ---  ---
...Missouri River
Jefferson City         23.0   25.0   30.0    6   15   <5   13   <5   10
Chamois                17.0   28.0   31.0    9   22   <5   <5   <5   <5
Hermann                21.0   26.0   33.0    9   26    7   13   <5    5
Washington             20.0   28.0   31.0    8   21   <5    6   <5   <5
St. Charles            25.0   30.0   36.0    9   22    6    8   <5   <5
...Mississippi River
Canton                 15.0   20.0   25.0   <5   <5   <5   <5   <5   <5
LaGrange               17.0   23.0   25.0   <5   <5   <5   <5   <5   <5
Quincy                 19.0   22.0   26.0   <5   <5   <5   <5   <5   <5
Lock & Dam 21          18.0   21.0   25.0   <5   <5   <5   <5   <5   <5
Hannibal               17.0   22.0   24.0   <5    6   <5   <5   <5   <5
Saverton               16.0   20.0   24.0   <5    8   <5   <5   <5   <5
Louisiana              15.0   20.0   25.0   <5   13   <5   <5   <5   <5
Clarksville            25.0   31.0   33.0   <5   13   <5   <5   <5   <5
Winfield               26.0   30.0   34.0   <5   11   <5   <5   <5   <5
Grafton                20.0   24.0   29.0    5    7   <5   <5   <5   <5
Alton                  21.0   24.0   31.0   <5   <5   <5   <5   <5   <5
Mel Price LD           21.0   29.0   34.0    7   13   <5    5   <5   <5
St. Louis              30.0   35.0   40.0    6   11   <5    6   <5   <5
Herculaneum            26.0   32.0   37.0    7   12    5    6   <5   <5
Chester                27.0   35.0   40.0   10   17    6    8   <5    6
...North Fabius River
Ewing                  11.0   17.0   20.0   10   27   <5   <5   <5   <5
...Middle Fabius River
Ewing                  12.0   17.0   20.0    6   23   <5    8   <5   <5
...South Fabius River
Taylor                 10.0   14.0   19.0    6   22   <5   10   <5   <5
...North River
Palmyra                13.0   16.0   22.0   <5   14   <5   <5   <5   <5
...Mid Fork Salt River
Holliday               17.0   22.0   26.0    9   19   <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   16   22   <5    8   <5   <5
Old Monroe             24.0   27.0   30.0   <5    7   <5    6   <5   <5
...Dardenne Creek
St. Peters             18.0   20.0   23.0   25   22   13   14    5    6
...Meramec River
Steelville             12.0   20.0   25.0   17   22   <5   <5   <5   <5
Sullivan               11.0   20.0   29.0   25   31    6    7   <5   <5
Pacific                15.0   23.0   27.0   14   21   <5    6   <5   <5
Eureka                 19.0   26.0   31.0   12   23    5    8   <5    7
Valley Park            18.0   21.0   27.0   15   26    8   14    6   11
Fenton                 23.0   29.0   32.0   13   24    6   11    6    6
Arnold                 24.0   35.0   38.0   12   21    6    7   <5    6
...Bourbeuse River
Union                  15.0   22.0   26.0   17   26    5    7   <5   <5
...Big River
Byrnesville            16.0   20.0   28.0   23   26    7   12   <5   <5
...Moreau River
Jefferson City         17.0   25.0   29.0   28   42   15   22    9   10
...Maries River
Westphalia             10.0   15.0   20.0   17   46   11   15   <5   <5
...Gasconade River
Rich Fountain          20.0   25.0   30.0   17   30    6   17    5    5
...Hinkson Creek
Columbia               15.0   18.0   20.0   15   19    5    5   <5   <5
...Osage River
St. Thomas             23.0   30.0   35.0    5    6   <5   <5   <5   <5
Mari-Osa Campground    19.0   22.0   25.0    7   13    5    9   <5    6
...La Moine River
Ripley                 22.0   23.0   27.0    7   15    5   14   <5   <5
...Kaskaskia River
Vandalia               18.0   24.0   26.0   38   49   20   27    8   18
Carlyle                16.5   23.0   27.0   32   43   <5   <5   <5   <5
New Athens             79.0   82.0   85.0   28   35   10   14    8   12

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:  10/28/2024 - 01/26/2025

Location              95%     90%     75%     50%     25%     10%      5%
--------            ------  ------  ------  ------  ------  ------   ------
...Missouri River
Jefferson City        5.6     5.6     5.7     7.0    10.7    15.0    24.2
Chamois               1.0     1.0     1.1     2.9     8.6    15.8    24.0
Hermann               4.3     4.3     4.5     7.1    11.2    19.5    30.1
Washington            2.1     2.1     2.3     4.9     8.6    17.2    25.8
St. Charles           9.4     9.4     9.7    12.4    16.0    23.8    31.7
...Mississippi River
Canton                2.8     2.8     3.1     3.9     5.1     6.8     8.8
LaGrange              3.7     3.7     4.0     4.8     6.0     7.7     9.7
Quincy               10.9    10.9    10.9    11.5    12.0    12.4    12.9
Lock & Dam 21         3.3     3.3     3.7     4.5     5.7     7.6     9.6
Hannibal              9.7     9.7     9.8    10.0    10.6    11.7    12.7
Saverton              4.3     4.3     4.6     5.3     6.6     8.5    10.1
Louisiana            11.8    11.8    11.8    11.9    12.0    12.0    12.1
Clarksville          13.7    13.7    14.0    15.0    16.7    18.7    20.6
Winfield             13.5    13.5    13.9    14.8    16.6    18.5    20.7
Grafton              14.6    14.6    14.7    14.9    15.2    15.4    20.0
Alton                19.4    19.4    19.4    19.4    19.4    19.4    19.4
Mel Price LD          3.2     3.2     4.1     5.4     8.2    15.1    26.8
St. Louis            -1.0    -0.9     0.7     2.9     8.1    22.1    34.8
Herculaneum          -4.0    -3.9    -2.0     0.5     6.1    20.1    32.6
Chester               2.6     3.5     5.9     9.7    13.5    27.6    39.4
...North Fabius River
Ewing                 3.2     3.4     3.9     5.1     6.8    10.8    11.8
...Middle Fabius River
Ewing                 2.9     3.0     3.3     4.0     6.0     9.5    12.8
...South Fabius River
Taylor                1.9     2.2     2.7     3.6     5.3     7.6    10.9
...North River
Palmyra               4.0     4.2     4.3     5.0     6.1     8.4    12.1
...Mid Fork Salt River
Holliday              4.6     4.6     5.2     6.5    10.8    15.7    17.8
...Salt River
New London            1.9     2.0     2.0     2.5     3.5     6.9     9.5
...Cuivre River
Troy                  5.8     6.1     7.9     9.1    15.4    23.5    24.8
Old Monroe            9.4     9.5     9.9    10.9    14.4    18.8    22.2
...Dardenne Creek
St. Peters            6.0     7.7     9.9    13.0    18.0    20.9    23.1
...Meramec River
Steelville            1.3     1.5     2.5     4.1     9.7    14.4    16.8
Sullivan              2.6     2.9     3.8     6.0    11.1    16.8    20.9
Pacific              -1.7    -1.4    -0.5     3.4    10.8    18.6    20.9
Eureka                3.0     3.3     4.3     7.6    15.4    20.9    28.1
Valley Park          -2.5    -2.1     1.0     5.1    13.2    20.2    34.0
Fenton                1.9     2.3     5.4     9.5    17.5    23.9    34.9
Arnold                6.8     7.0     8.4    11.2    16.3    25.7    37.5
...Bourbeuse River
Union                 2.9     3.0     3.2     6.3    12.4    18.6    22.2
...Big River
Byrnesville           2.3     2.9     5.2     7.8    14.0    19.1    22.0
...Moreau River
Jefferson City        1.6     1.7     3.0     6.6    18.9     27.8   34.3
...Hinkson Creek
Columbia              4.3     4.7     5.4     9.6    13.4    16.6    18.0
...Maries River
Westphalia            0.5     0.5     1.6     1.6     3.3     8.8    18.4
...Gasconade River
Rich Fountain         2.6     3.2     4.8     7.9    12.8    22.3    29.5
...Osage River
St. Thomas            3.7     3.7     3.7     5.3     8.7    14.7    24.6
Mari-Osa Campground   2.3     2.3     2.3     3.4     7.6    14.9    22.7
...La Moine River
Ripley                4.7     5.2     6.4     9.3    12.8    18.4    23.2
...Kaskaskia River
Vandalia              9.0     9.0     9.8    15.0    22.7    25.4    27.2
Carlyle              13.4    13.5    13.8    14.3    18.7    20.8    21.5
New Athens           69.3    70.1    72.5    74.4    79.4    82.5    90.8

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:  10/28/2024 - 01/26/2025

Location              95%     90%     75%     50%     25%     10%      5%
--------            ------  ------  ------  ------  ------  ------   ------
...Missouri River
Jefferson City        3.2     1.8     0.7     0.2    -1.2    -0.5    -0.7
Chamois               0.7    -2.1    -2.9    -3.4    -3.9    -4.2    -4.3
Hermann               4.0     2.6     1.3     0.5     0.1    -0.4    -0.6
Washington            1.9     0.9    -0.6    -1.4    -1.8    -2.3    -2.5
St. Charles           9.1     8.1     6.5     5.7     5.3     4.7     4.6
...Moreau River
Jefferson City       -1.0    -1.0    -1.0    -1.0    -1.0    -1.0    -1.0
...Hinkson Creek
Columbia              3.7     3.7     3.7     3.7     3.7     3.7     3.7
...Maries River
Westphalia            0.3     0.3     0.2     0.2     0.2     0.2     0.2
...Gasconade River
Rich Fountain         2.0     1.6     1.6     1.5     1.4     1.4     1.4
...Osage River
St. Thomas            2.1     2.1     2.1     2.1     2.1     2.1     2.1

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 outlook will be issued around the end of November.

$$
Fuchs
WFO ST LOUIS