Flood Potential Outlook
Issued by NWS Green Bay, WI

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PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE GREEN BAY WI
145 pm CST THU MAR 2 2017

...Spring Flood and Water Resource Outlook 2...

This flood outlook is for the NWS Green Bay service area. It covers
the time period from March 5th to June 3rd. This includes the
following rivers...Yellow...Wisconsin...Wolf...Little
Wolf...Waupaca...Fox...Oconto and Menominee.

...Forecast...

After a cold start for the start of March...temperatures are
expected to climb back above normal the latter half of this weekend
into early next week and then near normal for much of next week.
The next chance for widespread precipitation will be toward next
Monday.

The outlook for March into May indicates slightly above normal for
each temperatures and precipitation.

...Surface Conditions...

Soil conditions remain saturated.

A significant warm up mid February which produce a rapid snow melt,
followed with colder temperatures and snow late February into March
1st, led to a widely varied frost depth.  Frost depth still remains
around 8 to 20 inches, however some locations are reporting a thawed
region in that frost depth.

Due to recent snowfall events...snow depth ranged from 3 to 8 inches
across the region...with locally higher amounts across far North
Central Wisconsin. Snow water content of the snow was less than an
inch...but locally higher 1 to 2 inches over North Central
Wisconsin

...Current Streamflow conditions...

Above normal precipitation over North Central Wisconsin in 2016 which
included late fall...combined with runoff from the robust January
and February thaws have reduce the snow pack but were
producing above normal stream flows.

...Flood summary and potential threats...

The periods of above normal temperatures for each January and
February have reduced the snowpack across the region. Runoff from
recent snowfall and any future heavy snowfall will cause area rivers to
rise again, however assuming warming temperatures, flooding concerns
may eventually begin to focus more on excessive rainfall this spring.

Assuming conditions listed above...there is 25 to 50 percent
chance of minor flooding this spring again for part of the Wolf
river from Shawano to Lake Poygan and the Yellow River in Wood
County as well as the Menominee River.

--------------------------------

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:  03/05/2017 - 06/03/2017

                                       :    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
--------           -----  -----  ----- : ---  ---  ---  ---  ---  ---
:Wisconsin River
Merrill             11.0   13.5   15.0 :   7   17   <5    5   <5   <5
Rothschild          25.0   27.0   28.0 :   6   16   <5    7   <5   <5
Wisconsin Rapids    12.0   13.5   14.5 :  <5    5   <5   <5   <5   <5
:Yellow River
Babcock             12.0   15.9   16.6 :  38   71   <5   13   <5    8
:Oconto River
Oconto               9.0   12.0   14.0 :  14   16   <5   <5   <5   <5
:Upper Wolf River
Langlade            11.5   12.5   14.0 :  <5   <5   <5   <5   <5   <5
:Wolf River
Shiocton            12.0   13.5   15.0 :  25   35    6   10   <5   <5
New London           9.0   10.5   11.1 :  45   48   <5    5   <5   <5
:Little Wolf River
Royalton             5.0    8.0   10.0 :  31   41   <5   <5   <5   <5
:Waupaca River
Waupaca              6.0    7.5    9.0 :  <5    5   <5   <5   <5   <5
:Fox River
Appleton             8.4    9.0   10.5 :  <5   <5   <5   <5   <5   <5
:Menominee River
Florence             9.0   11.0   13.0 :  26   31    8   10   <5   <5
Niagara             13.0   15.0   16.0 :  20   28    7    7   <5   <5
Vulcan              15.0   17.0   19.0 :  14   25   <5    6   <5   <5
McAllister          15.0   18.0   19.0 :  48   55    7    9   <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: 03/05/2017 - 06/03/2017
Location              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:Wisconsin River
Merrill               7.5    7.9    8.3    8.9    9.8   10.3   11.8
Rothschild           18.3   19.1   19.8   21.3   22.4   23.7   25.4
Wisconsin Rapids      5.5    5.7    6.0    7.3    8.1    9.9   10.3
:Yellow River
Babcock               5.9    7.0    8.2   10.9   13.3   15.2   15.6
:Oconto River
Oconto                6.8    6.8    7.3    7.7    8.5    9.5   10.4
:Upper Wolf River
Langlade              9.1    9.2    9.5    9.7   10.0   10.4   10.5
:Wolf River
Shiocton              9.7    9.9   10.6   11.5   12.0   13.0   13.7
New London            7.7    8.0    8.4    8.9    9.4    9.9   10.1
:Little Wolf River
Royalton              3.2    3.3    3.7    4.3    5.1    5.8    6.8
:Waupaca River
Waupaca               2.6    2.7    3.1    3.5    4.1    4.5    4.9
:Fox River
Appleton              6.9    6.9    6.9    7.3    7.7    7.9    7.9
:Menominee River
Florence              6.1    6.6    7.3    8.0    9.1   10.6   11.1
Niagara               9.3   10.1   10.7   11.6   12.8   14.7   15.3
Vulcan                9.7   10.5   11.3   12.4   13.9   15.8   16.9
McAllister           12.8   13.3   14.3   14.9   16.1   17.3   18.9

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: 03/05/2017 - 06/03/2017
Location              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:Wisconsin River
Merrill               5.3    5.3    5.3    4.9    4.7    4.6    4.6
Rothschild           14.2   14.1   14.1   13.7   13.5   13.3   12.6
Wisconsin Rapids      3.6    3.5    3.5    3.2    3.1    1.4    1.3
:Yellow River
Babcock               2.2    2.1    2.0    1.9    1.9    1.9    1.9
:Oconto River
Oconto                5.4    5.3    5.1    5.0    4.8    4.7    4.7
:Upper Wolf River
Langlade              8.1    8.1    8.0    7.9    7.8    7.8    7.8
:Wolf River
Shiocton              6.8    6.6    5.8    4.7    4.0    3.6    3.5
New London            4.3    4.1    3.5    3.0    2.5    2.2    2.2
:Little Wolf River
Royalton              1.5    1.5    1.4    1.3    1.3    1.2    1.2
:Waupaca River
Waupaca               1.7    1.7    1.6    1.6    1.5    1.5    1.5
:Fox River
Appleton              5.7    5.6    5.4    5.2    5.0    4.9    4.9
:Menominee River
Florence              3.6    3.6    3.6    3.5    3.4    3.4    3.4
Niagara               5.9    5.9    5.8    5.7    5.5    5.5    5.5
Vulcan                5.9    5.9    5.8    5.7    5.5    5.5    5.5
McAllister            9.7    9.7    9.6    9.4    9.3    9.2    9.2

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/grb for more weather and water
information.

Additional web sites and information.

Latest snowpact from NOHRCS  www.nohrsc.noaa.gov/nsa

Current streamflows.  waterdata.usgs.gov/wi/nwis/rt

Long term forecast information.  www.cpc.noaa.gov

An optional flood outlook may be issued later March if needed.

$$



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