Flood Potential Outlook
Issued by NWS Sioux Falls, SD

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FGUS73 KFSD 031553
ESFFSD
SDC005-011-027-035-061-067-079-083-087-099-101-111-125-127-135-
MNC033-063-081-083-101-105-117-133-NEC043-051-
IAC021-035-041-059-093-119-141-143-149-167-193-291800-

PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE SIOUX FALLS SD
950 AM CST THU MAR 03 2016

...Spring Flood Outlook...

This spring flood outlook is for the rivers and streams in southeast
South Dakota, southwest Minnesota, northwest Iowa, and extreme
northeast Nebraska.

With very little snow cover remaining across the area, the flood
threat through this spring will be largely determined by future rain
or snow fall. The outlook for the next 2 weeks indicates the best
chances are for normal to below normal precipitation. The 30 day
outlook for the entire month of March shows increased chances for
above normal precipitation. The 90 day outlook for March through May
shows equal chances of above normal, normal, or below normal
precipitation.

For the James and Vermillion river basins, the chances for minor,
moderate, or major flooding are below normal. For the Big Sioux
River, chances for minor, moderate or major flooding are below normal
for the middle and upper portions of the basin, while the lower Big
Sioux has above normal chances for minor flooding and normal chances
for moderate or major flooding. For the Rock, Floyd and Redwood river
basins, chances for minor, moderate, or major flooding are near
normal. For the Little Sioux and Des Moines river basins, there are
above normal chances for minor flooding, and normal chances for
moderate or major flooding.

...Current Snow Conditions...

Snow depths are generally less than 3 inches across the entire
region, with nearly all of this snow being from recent snow falls in
the past week. The water equivalent of the snow pack is less than 1
inch. There are still areas that have additional snow in ditches,
shelterbelts, and other shaded areas left over from snowfall earlier
this winter.

...Current Soil Conditions...

There is little to no frost remaining in the soils from Interstate 90
south, with frost depths increasing north of there to where there is
still 10 to 20 inches of frozen soil in areas along and north of
Highway 14.

Soil moisture is above normal for the entire region following much
above normal rainfall last fall and the melting of the snow that fell
earlier this winter. Modeled soil moisture anomalies range from
around 1 inch above normal in the far northern and western portions
of the region to 6 inches above normal in western Iowa. Soil moisture
sensors indicate 20 to 45% saturation across the area, with the
highest values east of Interstate 29.

...Current River Conditions...

River levels and flows continue to run above normal to much above
normal. There are also still some rivers and streams that have some
ice cover that needs to melt or be flushed downstream.

...Probabilistic Outlooks...

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:  03/05/2016  - 06/03/2016

                                       :    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
--------           -----  -----  ----- : ---  ---  ---  ---  ---  ---
:Floyd River
Sheldon             12.0   14.0   16.0 :  29   35   19   23   <5   <5
Alton               12.0   16.0   18.0 :  49   38   16   19   <5    5
Le Mars             20.0   21.0   24.0 :  17   17   11   13   <5   <5
:West Branch Floyd River
Struble             14.0   15.0   16.0 :  11   13    6    9   <5   <5
:Floyd River
Merrill             12.0   14.0   16.0 :  15   10    6    8    5    5
James               26.0   30.0   34.0 :  <5    5   <5   <5   <5   <5
:Little Sioux River
above Spencer       10.0   13.0   15.0 :  46   57   14   20   <5    8
at Spencer          10.0   14.0   16.0 :  89   63   17   18   <5    9
:Ocheyedan River
Spencer              8.0    9.5   10.5 :  52   52   30   27   14   16
:Little Sioux River
Linn Grove          18.0   19.5   21.0 :  88   65   42   40   20   19
Cherokee            17.0   21.0   24.0 :  45   43   22   20   <5    6
Correctionville     19.0   20.0   21.0 :  27   20   15   17   12   10
:West Fork Ditch
Hornick             20.0   22.0   27.0 :  22   24   14   19    6   <5
:Perry Creek
Sioux City          24.0   26.0   28.0 :  <5   <5   <5   <5   <5   <5
:Big Sioux River
Brookings            9.0   10.5   12.0 :  38   51   24   38    8   25
Dell Rapids         12.0   14.0   15.0 :  23   36   11   25    7   17
Sioux Falls 60th St 12.0   14.0   16.0 :  15   35    9   24   <5   10
:Skunk Creek
Sioux Falls         11.5   15.0   17.0 :  <5   11   <5    5   <5   <5
:Big Sioux River
Sioux Falls N Cliff 16.0   18.0   31.0 :  16   35   11   31   <5   <5
:Split Rock Creek
Corson               8.5   11.0   14.0 :  26   36   11   21    7    9
:Rock River
Luverne             10.0   12.0   14.0 :  11   18   <5    9   <5   <5
Rock Rapids         13.0   16.0   19.0 :  67   42   23   23    9   13
Rock Valley         16.0   17.0   19.0 :  27   28   18   18    8   11
:Big Sioux River
Hawarden            15.0   20.0   23.0 :  81   53   20   29    8   14
Akron               16.0   18.0   20.0 :  81   51   56   43   30   31
Sioux City          32.0   38.0   41.0 :  <5   <5   <5   <5   <5   <5
:James River
Huron               11.0   13.0   15.0 :  27   44   16   32   11   23
Forestburg          12.0   14.0   16.0 :  26   45   19   30    5   17
Mitchell            17.0   20.0   22.0 :  26   48   10   27    5   15
:Firesteel Creek
Mount Vernon         8.0   13.0   15.0 :  16   41    6   16   <5    5
:James River
Scotland            13.0   14.0   16.0 :  20   43   15   34    8   24
Yankton             12.0   14.0   16.0 :  10   33    8   27    7   21
:West Fork Vermillion River
Parker               9.0   10.0   11.0 :   5   11   <5    8   <5   <5
:East Fork Vermillion River
Parker              12.0   14.0   16.0 :   6   29   <5   14   <5   <5
:Vermillion River
Davis               11.0   13.0   15.0 :  16   40    9   33   <5    8
Wakonda             14.0   15.5   17.0 :  27   41   17   36   15   34
Vermillion          21.0   22.0   30.0 :  11   31    8   30   <5   <5
:Redwood River
Marshall            14.0   15.0   16.5 :  15   17   11   15    6   10
:West Fork Des Moines River
Jackson             12.0   14.0   16.0 :  42   27   11   16   <5   <5

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: 03/05/2016  - 06/03/2016
Location              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:Floyd River
Sheldon               6.6    7.6    8.1    9.3   12.5   14.9   15.3
Alton                 8.4    9.2   10.4   11.6   15.0   16.9   17.8
Le Mars              12.2   13.2   14.9   16.1   19.3   21.1   22.7
:West Branch Floyd River
Struble               5.9    7.4    8.1    9.7   11.1   14.4   15.1
:Floyd River
Merrill               2.8    3.6    5.0    6.5    9.3   12.4   15.3
James                11.9   12.3   13.7   15.1   18.0   20.9   24.6
:Little Sioux River
above Spencer         8.1    8.6    9.0    9.9   12.2   13.8   14.4
at Spencer            9.3    9.9   10.5   11.3   13.5   14.8   15.5
:Ocheyedan River
Spencer               5.8    6.4    7.0    8.1   10.0   11.2   11.6
:Little Sioux River
Linn Grove           17.7   17.8   18.3   18.9   20.7   22.3   23.5
Cherokee             13.7   13.7   14.9   16.4   20.4   22.4   22.8
Correctionville      12.3   12.3   12.3   14.3   19.6   21.9   22.7
:West Fork Ditch
Hornick              11.0   11.7   14.1   16.2   19.1   25.3   27.5
:Perry Creek
Sioux City            7.3    7.6    8.0    8.6    9.2   10.5   13.4
:Big Sioux River
Brookings             4.1    4.4    5.7    8.2   10.4   11.6   12.4
Dell Rapids           6.8    6.8    7.3    9.6   11.9   14.4   15.1
Sioux Falls 60th St   5.1    5.1    5.6    8.2   11.1   13.8   14.8
:Skunk Creek
Sioux Falls           5.4    5.4    5.8    6.7    7.5    8.4    9.6
:Big Sioux River
Sioux Falls N Cliff   8.3    8.4    9.9   12.1   14.4   18.6   21.9
:Split Rock Creek
Corson                4.3    4.8    5.8    7.1    8.7   11.8   14.6
:Rock River
Luverne               5.7    5.8    6.7    7.6    8.6   10.4   11.7
Rock Rapids          11.3   11.5   12.8   14.0   15.7   18.7   20.5
Rock Valley           9.9   10.3   12.2   13.6   16.3   18.2   19.4
:Big Sioux River
Hawarden             13.0   14.4   16.0   17.6   19.2   22.6   24.4
Akron                13.5   15.0   17.1   18.8   20.2   22.4   23.3
Sioux City           14.7   15.1   17.3   19.8   22.4   29.0   32.7
:James River
Huron                 9.6    9.6    9.6    9.8   11.7   15.4   16.7
Forestburg            6.6    6.6    6.6    7.2   13.3   14.9   16.0
Mitchell             12.2   12.2   12.2   12.7   17.8   19.9   22.2
:Firesteel Creek
Mount Vernon          3.1    3.1    3.1    4.9    7.2   10.9   13.3
:James River
Scotland              5.8    5.8    5.8    6.6   12.2   14.4   17.9
Yankton               3.5    3.5    3.5    4.3    8.3   12.2   18.9
:West Fork Vermillion River
Parker                1.3    1.3    1.3    2.0    3.1    4.5    8.3
:East Fork Vermillion River
Parker                4.6    4.6    4.8    5.8    8.7   10.3   12.7
:Vermillion River
Davis                 4.9    4.9    5.1    6.8   10.1   12.9   14.1
Wakonda               6.5    6.5    6.5    9.8   14.2   17.3   17.5
Vermillion            8.8    8.8    8.8   10.6   14.1   21.8   25.1
:Redwood River
Marshall              8.3    8.9    9.7   10.9   12.7   15.5   16.9
:West Fork Des Moines River
Jackson              10.2   10.3   10.5   11.5   12.7   14.1   14.9

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: 03/05/2016  - 06/03/2016
Location              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:Floyd River
Sheldon               4.3    4.1    4.0    4.0    4.0    4.0    4.0
Alton                 6.5    6.4    6.1    5.9    5.7    5.6    5.6
Le Mars               7.9    7.4    6.5    6.5    6.5    6.5    6.5
:West Branch Floyd River
Struble               4.7    4.7    4.5    4.3    4.2    4.1    4.1
:Floyd River
Merrill               1.9    1.8    1.4    1.1    0.8    0.5    0.4
James                11.0   10.9   10.6   10.3   10.2   10.1   10.0
:Little Sioux River
above Spencer         7.1    6.7    6.3    6.0    5.7    5.6    5.5
at Spencer            7.7    7.1    5.5    4.4    3.7    3.2    3.0
:Ocheyedan River
Spencer               4.5    4.3    3.7    3.3    3.2    3.0    2.9
:Little Sioux River
Linn Grove           17.2   16.9   16.6   16.4   16.2   16.2   16.1
Cherokee             11.2    9.9    8.8    7.5    6.9    6.4    5.9
Correctionville       9.5    8.0    7.2    6.3    5.4    5.2    4.8
:West Fork Ditch
Hornick               7.7    7.3    7.0    6.5    6.3    6.2    6.1
:Perry Creek
Sioux City            7.1    7.1    7.0    6.8    6.6    6.3    6.2
:Big Sioux River
Brookings             3.2    3.1    2.9    2.8    2.5    2.4    2.4
Dell Rapids           4.6    4.4    4.2    4.0    3.7    3.6    3.6
Sioux Falls 60th St   2.6    2.3    2.2    1.9    1.6    1.6    1.5
:Skunk Creek
Sioux Falls           4.5    4.4    4.2    4.1    4.0    3.9    3.9
:Big Sioux River
Sioux Falls N Cliff   6.5    6.3    6.2    6.0    5.7    5.6    5.6
:Split Rock Creek
Corson                2.7    2.6    2.5    2.5    2.4    2.3    2.3
:Rock River
Luverne               4.1    4.0    3.9    3.8    3.7    3.7    3.7
Rock Rapids           8.8    8.6    8.4    8.2    8.0    7.9    7.9
Rock Valley           6.4    6.3    5.6    5.3    4.9    4.8    4.6
:Big Sioux River
Hawarden              9.0    8.3    7.3    6.6    5.9    5.6    5.5
Akron                 9.3    8.6    7.6    7.1    6.3    6.0    5.8
Sioux City           12.8   12.4   10.5   10.5   10.5   10.5   10.5
:James River
Huron                 9.5    9.5    9.3    9.1    9.1    9.0    9.0
Forestburg            6.2    6.1    5.5    5.2    4.9    4.8    4.8
Mitchell             12.0   11.8   11.3   10.7   10.3   10.1   10.0
:Firesteel Creek
Mount Vernon          2.9    2.7    2.6    2.6    2.5    2.5    2.5
:James River
Scotland              5.6    5.5    5.3    5.0    4.8    4.7    4.7
Yankton               3.1    3.0    2.6    2.1    2.0    2.0    2.0
:West Fork Vermillion River
Parker                0.9    0.7    0.6    0.5    0.2    0.2    0.2
:East Fork Vermillion River
Parker                4.1    4.0    3.8    3.5    3.4    3.4    3.4
:Vermillion River
Davis                 3.3    3.0    2.7    2.5    2.4    2.4    2.4
Wakonda               4.7    4.3    4.0    3.7    3.6    3.6    3.6
Vermillion            4.6    3.7    3.3    2.9    2.7    2.6    2.6
:Redwood River
Marshall              7.2    7.1    7.0    6.9    6.8    6.7    6.7
:West Fork Des Moines River
Jackson               7.1    6.7    6.3    5.3    4.8    4.5    4.4

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/fsd for more weather and water
information.

The next outlook will be issued toward the end of March.

$$

MG





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