National Weather Service United States Department of Commerce

 

Figure 1: Snow Water Equivalent Image. (Courtesy of NOHRSC)
Figure 2: USGS Current Streamflow Analysis
Figure 3: 180 Day Percentage of Mean Precipitation Analysis (Courtesy of Midwest Climate Center)
Figure 4: Palmer Drought Severity Index
Figure 5: Soil Moisture (mm)
Figure 6: Three Month Temperature Outlook
Figure 7: Three Month Precipitation Outlook

NWS
St. Louis, Missouri

Spring Flood Outlook
Issued: March 7, 2019

Snow Water EquivalentCurrent Snow Water Equivalent

Streamflow AnalysisUSGS Stream Analysis

  30 Day Rainfall DeparturePrecipitation 30 Day Percentage of Mean

Soil Moisture PercentileCurrent Soil Moisture

1-Month Precip Outlook3 Month Precipitation Outlook

1-Month Temp Outlook3 Month Temperature Outlook

3-Month Precip Outlook3 Month Precipitation Outlook

3-Month Temp Outlook3 Month Temperature Outlook

Probabilistic Hydrologic Outlook
National Weather Service ST. LOUIS MO
305 PM CST THU MAR 07 2019

...Spring Flood and Water Resources Outlook Number 2...
...Significant flood chances continue to increase along the
   Mississippi and Missouri Rivers...
...Local tributaries remain with above normal flood chances...

This outlook uses the term St. Louis service area to refer to the
Mississippi River from above Canton, Missouri to above Cape
Girardeau, Missouri, the Missouri River from above Jefferson City,
Missouri to its confluence with the Mississipi River, the Illinois
River from Beardstown, Illinois to its confluence with the
Mississippi River, and the tributaries in central and eastern
Missouri, and west central and southwestern Illinois.

There is no flooding occurring anywhere within the St. Louis service
area, so the modeling results presented below are not affected by
current flow conditons.  That said, flows throughout the region are
above normal. These elevated flows enhance the likelihood of flood
potential.

This outlook is based on current streamflows and soil moisture over
the area, upstream snowpack in the Mississippi, Missouri, and
Illinois River basins, and the current river forecasts as a starting
point.  In general, more than average rainfall could cause
additional flooding over the area, while less than average rainfall
could keep rivers from reaching expected crests.

...Elevated flood potential across local tributaries...

After more than 3 months of above average precipitation across
Missouri and Illinois, above average chances of flooding remain in
place along most local tributaries in the St. Louis service area
over the next 90 days.  The least likely areas for flooding continue
to be across central Missouri, where probabilities for minor
flooding range from 8 percent below average on the Maries River to
at least 12 percent above average along the Moreau River. Farther
east and north, flood probabilities are higher. Across eastern
Missouri, minor flood probabilities range from the seasonal average
at the Bourbeuse River up to 6 to at least 25 percent above the
seasonal average along the Meramec River.  In northeastern Missouri,
minor flood probabilities range from the seasonal average along the
North River up to 50 percent above the seasonal average along the
Middle Fabius River.  In Illinois, the probabilities for minor
flooding range from 10 percent above the seasonal average along the
La Moine River up to 17 percent above the seasonal average on the
upper Kaskaskia River.  While the probabilities for moderate or
greater flooding are also above normal for Illinois tributaries,
those probabilities for moderate or greater flooding are closer to
normal for most tributaries in Missouri.

...Significant flood risk on area`s major rivers...

For the Mississippi, Missouri, and Illinois rivers, this spring
flood outlook appears even more daunting than 2 weeks ago.  This is
the highest flood risk along this part of the Mississippi since
these probabilistic outlooks have been issued, or since at least
2003. Along the Missouri River, moderate flooding remains likely at
Jefferson City, Hermann, and St. Charles, though the likelihood is
for minor flooding at Chamois, Gasconade, and Washington due to
higher moderate flood thresholds at these gages.  Along the
Mississippi River, major flooding is now likely for all gages from
Quincy to Chester except at Louisiana and Grafton, where major flood
probabilities are just under 50 percent.  For most gaging locations
along the Mississippi River, likely crest levels have risen 1 to 2
feet in the past 2 weeks.

Over the upper Mississippi River basin in Minnesota, Wisconsin, and
much of Iowa into northern Missouri, snow water equivalents and snow
depths have mostly increased over the past 2 weeks.  At least 2
inches of snow water equivalent, the depth of ice and snow cover
after it is melted to water, exists north of a line from the
northwest corner of Missouri to Des Moines to north of Milwaukee. At
least 4 inches of snow water equivalent remains over most of
Minnesota and northern Wisconsin.  For the Missouri River basin
above Kansas City and below Gavins Point Dam, snow depths and snow
water equivalents are also well above the seasonal averages.
Throughout Missouri, Illinois, and the major river basins to the
north and west, streamflow and soil moisture remain well above
average for this time of year. Conditions are favorable for
significant flooding along our navigable rivers, particularly if
rainfall over the spring months is near or above the seasonal
average.

...Extended weather outlooks...

In the near term, the Climate Prediction Center calls for
precipitation to be most likely above normal in the 6 to 10 day
period, and below normal in the 8 to 14 day period. Temperatures
will most likely be near average in the 6 to 10 day period, and
below normal during the 8 to 14 day outlooks.  For the month of
March, the outlook calls for near to above normal precipitation. The
temperature outlook for March indicates a likelihood of colder than
average temperatures. For the spring months of March through May,
the 3-month outlook indicates equal chances of below normal, near
normal, or above normal precipitation and temperatures.  To the
south of the St. Louis metro, the most likely result is above normal
precipitation.

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:  03/11/2019 - 06/09/2019

                                       :    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 LD20         14.0   20.0   25.0 : >95   65   91   14   25   <5
LaGrange            18.0   23.0   25.0 : >95   39   65    8   35   <5
Quincy              17.0   22.0   26.0 : >95   63  >95   28   65    8
Quincy LD21         17.0   21.0   25.0 : >95   56  >95   27   65    8
Hannibal            16.0   22.0   24.0 : >95   66   89   14   69    8
Saverton LD22       16.0   20.0   22.0 : >95   63  >95   37   93   19
Louisiana           15.0   20.0   25.0 : >95   71  >95   34   45    5
Clarksville LD24    25.0   31.0   33.0 : >95   71  >95   28   88   12
Winfield LD25       26.0   30.0   34.0 : >95   65  >95   39   68    8
Grafton             18.0   24.0   29.0 : >95   79   92   36   49    7
Mel Price LD        21.0   29.0   34.0 : >95   74   81   39   56    9
St. Louis           30.0   35.0   40.0 : >95   65   87   47   63   15
Chester             27.0   35.0   40.0 : >95   81  >95   60   68   25
:North Fabius River
Ewing               11.0   14.0   18.0 : >95   53   30   27   11   11
:Middle Fabius River
Ewing               12.0   17.0   19.5 : >95   46   17   13   10    9
:South Fabius River
Taylor               9.5   14.0   19.0 : >95   54   16   14   <5   <5
:North River
Palmyra             13.0   16.0   22.0 :  56   56   36   33   <5   <5
:Mid Fork Salt River
Holliday            17.0   22.0   26.0 :  56   46    7   <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   52   27   28    8    8
Old Monroe          24.0   27.0   30.0 : >95   59   93   24   60   10
:Dardenne Creek
St. Peters          18.0   20.0   23.0 :  30   30   19   18   <5   <5
:Bourbeuse River
Union               15.0   22.0   26.0 :  50   50   10   10   <5   <5
:Big River
Byrnesville         16.0   20.0   28.0 :  69   61   24   22   <5   <5
:Meramec River
Steelville          12.0   20.0   25.0 :  53   41    6    6   <5   <5
Sullivan            11.0   20.0   29.0 : >95   70   15   13   <5   <5
Pacific             15.0   23.0   27.0 :  55   46    9    9   <5   <5
Eureka              19.0   26.0   31.0 :  48   42   20   17   12    9
Valley Park         16.0   19.0   25.0 : >95   71   85   48   41   27
Fenton              25.0   29.0   32.0 :  87   46   64   21   38   13
Arnold              24.0   35.0   38.0 : >95   79   80   28   66   22
:Kaskaskia River
Vandalia            18.0   24.0   26.0 : >95   78   26   24   11   11
Carlyle Tailwater  423.5  431.0  435.0 :  24   41   <5   <5   <5   <5
:La Moine River
Ripley              22.0   23.0   27.0 :  52   42   47   35   12    8
:Moreau River
Jefferson City      17.0   25.0   29.0 : >98   86   45   42   21   18
:Maries River
Westphalia          10.0   15.0   20.0 :  39   47   18   19   <5   <5
:Gasconade River
Rich Fountain       20.0   25.0   30.0 :  35   37   24   26    5    6
:Osage River
St. Thomas          23.0   30.0   35.0 :  15   16   <5   <5   <5   <5
Mari-Osa Campgrnd   19.0   22.0   25.0 :  73   63   48   25   21   13
:Missouri River
Jefferson City      23.0   25.0   30.0 :  97   59   85   40   46   12
Chamois             17.0   28.0   31.0 : >98   72   28   10   11    5
Gasconade           22.0   34.0   37.0 : >98   81   30   12   10   <5
Hermann             21.0   26.0   33.0 : >98   79   88   49   29   11
Washington          20.0   28.0   31.0 : >98   70   42   14   21    9
St. Charles         25.0   30.0   36.0 : >98   74   64   25   21    8

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: 03/11/2019 - 06/09/2019
Location              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:Mississippi River
Canton LD20          19.4   20.2   21.6   22.8   25.0   26.9   27.9
LaGrange             20.3   21.1   22.5   23.6   25.9   27.8   28.8
Quincy               23.0   23.9   25.5   27.0   29.7   31.8   32.4
Quincy LD21          21.7   22.7   24.4   26.2   29.0   31.1   32.0
Hannibal             21.0   21.7   23.5   25.3   28.5   30.7   32.2
Saverton LD22        21.5   22.3   24.0   25.6   28.2   29.4   30.0
Louisiana            21.0   21.6   23.2   24.4   26.8   28.4   29.8
Clarksville LD24     31.6   32.3   33.7   34.9   36.8   38.0   39.1
Winfield LD25        31.7   32.3   33.6   34.8   37.2   38.4   39.5
Grafton              22.8   24.7   25.9   28.5   33.7   35.4   36.3
Mel Price LD         27.0   28.1   30.4   34.2   36.9   39.3   41.4
St. Louis            33.5   34.7   37.4   41.6   44.7   47.3   49.0
Chester              36.3   36.9   38.7   42.3   46.1   48.0   49.8
:North Fabius River
Ewing                12.1   12.2   12.3   12.6   15.1   18.8   21.0
:Middle Fabius River
Ewing                12.7   12.8   12.8   13.1   15.7   19.0   21.4
:South Fabius River
Taylor                9.6    9.7    9.9   10.5   12.7   15.3   17.5
:North River
Palmyra              10.3   10.3   10.8   14.2   16.9   20.0   21.2
:Mid Fork Salt River
Holliday             15.7   15.7   16.1   17.5   18.9   20.8   22.3
:Salt River
New London            9.7    9.7    9.8   10.5   12.8   15.2   16.5
:Cuivre River
Troy                 18.9   19.0   19.2   21.3   25.1   27.6   29.6
Old Monroe           26.2   27.9   29.4   31.0   33.9   35.2   36.4
:Dardenne Creek
St. Peters           10.6   10.7   11.2   14.5   19.1   21.2   22.1
:Bourbeuse River
Union                10.9   11.1   12.4   14.9   19.2   22.3   25.3
:Big River
Byrnesville          14.9   15.0   15.4   17.3   19.8   22.5   24.8
:Meramec River
Steelville            8.5    8.5    8.9   12.5   14.6   16.6   20.1
Sullivan             11.5   11.5   12.1   15.2   18.5   21.6   25.3
Pacific              11.2   11.5   12.8   15.6   19.0   22.8   25.2
Eureka               14.4   14.6   16.2   18.7   25.2   31.6   34.0
Valley Park          16.0   17.7   20.9   24.0   30.3   35.8   40.3
Fenton               24.2   24.5   26.9   30.5   33.8   37.0   39.5
Arnold               33.1   33.6   36.2   39.9   42.4   45.4   46.0
:Kaskaskia River
Vandalia             19.8   19.9   20.2   21.3   24.2   26.2   27.0
Carlyle Tailwater   419.5  419.7  420.4  421.9  423.4  424.5  425.2
:La Moine River
Ripley               19.5   19.8   20.2   22.3   25.5   27.3   28.1
:Moreau River
Jefferson City       19.0   19.0   19.0   23.6   28.3   33.9   40.1
:Maries River
Westphalia            4.1    4.1    5.3    8.1   13.1   16.5   18.2
:Gasconade River
Rich Fountain        10.7   10.7   11.8   17.0   23.9   28.6   31.2
:Osage River
St. Thomas           11.6   12.0   12.9   14.4   20.3   26.1   27.9
Mari-Osa Campgrnd    17.5   18.2   18.8   21.8   24.3   27.7   30.8
:Missouri River
Jefferson City       23.3   24.2   26.4   28.6   31.9   37.2   40.7
Chamois              20.4   21.0   22.5   25.9   29.0   31.6   32.4
Gasconade            28.0   28.4   30.1   33.1   35.3   37.1   37.9
Hermann              24.5   25.8   26.5   31.2   34.1   36.1   36.3
Washington           21.4   22.5   23.3   27.7   30.4   33.0   34.1
St. Charles          26.7   27.8   28.6   32.9   35.3   37.9   39.3

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: 03/11/2019 - 06/09/2019
Location              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:Mississippi River
Canton LD20           7.4    7.4    7.3    7.2    6.7    5.5    4.9
LaGrange              8.3    8.3    8.2    8.1    7.6    6.4    5.8
Quincy               12.6   12.6   12.6   12.6   12.4   12.1   11.9
Quincy LD21           8.4    8.3    8.2    8.2    7.3    6.0    5.4
Hannibal             12.0   12.0   11.9   11.9   11.2   10.7   10.4
Saverton LD22         8.8    8.8    8.7    8.7    7.7    6.8    6.2
Louisiana            12.1   12.1   12.1   12.1   12.0   12.0   11.9
Clarksville LD24     19.2   19.1   19.0   19.0   17.9   16.8   16.0
Winfield LD25        19.0   19.0   18.9   18.8   17.8   16.6   15.8
Grafton              15.7   15.7   15.7   15.7   15.3   15.0   14.9
Mel Price LD         12.2   12.2   12.1   12.0   10.4    6.8    5.9
St. Louis            14.2   14.2   14.1   14.0   12.5    7.1    5.1
Chester              17.6   17.5   17.4   17.4   15.7   10.9    8.9
:North Fabius River
Ewing                 3.8    3.7    3.6    3.5    3.4    3.3    3.2
:Middle Fabius River
Ewing                 3.3    3.2    3.2    3.0    3.0    3.0    2.9
:South Fabius River
Taylor                2.2    2.2    2.0    1.9    1.8    1.7    1.7
:North River
Palmyra               4.1    4.0    4.0    3.9    3.8    3.8    3.8
:Mid Fork Salt River
Holliday              4.6    4.5    4.4    4.4    4.3    4.2    4.2
:Salt River
New London            5.4    5.2    5.1    4.4    2.4    2.2    2.2
:Cuivre River
Troy                  6.2    6.0    5.7    5.5    5.3    5.2    5.2
Old Monroe           16.2   16.1   16.0   15.2   13.8   12.6   11.7
:Dardenne Creek
St. Peters            1.9    1.9    1.7    1.5    1.5    1.4    1.4
:Bourbeuse River
Union                 2.6    2.4    2.3    2.2    2.0    2.0    1.9
:Big River
Byrnesville           3.5    3.2    2.7    2.4    2.2    2.0    1.9
:Meramec River
Steelville            2.6    2.4    2.2    2.0    1.8    1.8    1.7
Sullivan              3.4    3.1    2.9    2.6    2.4    2.4    2.3
Eureka                4.8    4.3    4.0    3.7    3.5    3.4    3.4
Fenton               10.5   10.5    7.9    5.0    2.9    2.0    1.9
Arnold               12.8   12.7   12.6   12.5   11.0    7.6    6.8
:Kaskaskia River
Vandalia              8.7    7.1    4.0    3.4    3.1    3.0    3.0
Carlyle Tailwater   417.3  417.3  416.3  411.6  411.2  411.2  411.2
:La Moine River
Ripley                7.2    6.8    6.0    5.5    5.3    5.1    5.0
:Moreau River
Jefferson City        2.1    2.1    1.8    1.4    1.1    1.1    1.0
:Maries River
Westphalia            1.6    1.4    1.1    0.5    0.3    0.3    0.3
:Gasconade River
Rich Fountain         4.9    4.7    4.3    3.7    3.3    3.2    3.2
:Osage River
St. Thomas            3.9    2.7    2.5    1.9    1.4    1.2    1.1
:Missouri River
Jefferson City        7.4    7.4    7.4    7.4    7.4    7.4    7.3
Chamois               2.2    2.2    2.2    2.2    2.2    2.2    1.9
Gasconade             6.5    6.5    6.5    6.5    6.5    6.5    6.1
Hermann               8.1    8.1    8.1    8.1    8.1    8.1    7.5
Washington            5.3    5.3    5.3    5.3    5.3    5.2    4.6
St. Charles          12.2   12.2   12.2   12.2   12.2   12.0   11.2

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 toward the end of the month.

$$