Flood Potential Outlook
Issued by NWS Omaha/Valley, NE

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000
FGUS73 KOAX 131826
ESFOAX
NEC003-023-025-039-053-055-067-095-107-109-119-127-139-141-147-151-
153-155-159-167-IAC071-085-133-137-145-155-051800-

Probabilistic Hydrologic Outlook
National Weather Service Omaha NE
1220 PM CST Thu Feb 13 2020

...Elevated Risk for Flooding This Spring...

.2020 Spring Flood Outlook...

The overall risk for flooding this spring can be characterized as
above-normal. The primary reason for this increased threat is due to
high river levels, left over from 2019, and generally elevated soil
moisture across the region. The rivers of most concern for flooding
are the: Missouri River, Big Blue River, Wahoo Creek, Salt Creek,
Shell Creek, N.F. Elkhorn River and the Nishnabotna River (West and
East). Along the Missouri River, there is a greater than 90% chance
the river will reach flood stage below the Platte River confluence.
Upstream of the Platte River, Blair and Omaha, the Missouri River has
a lower chance of reaching minor flood stage, but the chance is still
much higher than normal.

It isn`t all bad news as several typical indicators for flood risk
are below-normal this year. As of 13 Feb, there is little to no snow
cover across Nebraska or western Iowa and most rivers have lost their
ice, leading to a low, to near zero, ice jam threat.

Compared to this time last year, conditions are much different in
several ways. The primary differences being the lack of significant
river ice, lack of snowpack, shallower frost depths and February is
forecast to end with above-normal temperatures.

Future flooding will be highly dependent on the location and
intensity
of precipitation, especially heavy rain, over the coming weeks.

For images and more detailed information on the flood risk, visit the
following link:

www.weather.gov/omaha/SpringFloodOutlook

The next update for this outlook is February 27th, 2020.

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:  02/15/2020  - 05/15/2020

                                       :    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
--------           -----  -----  ----- : ---  ---  ---  ---  ---  ---
:Niobrara River
Verdel               7.0    9.0   10.0 :  <5   <5   <5   <5   <5   <5
:Ponca Creek
Verdel              13.5   15.0   17.0 :  10    5    9   <5   <5   <5
:Elkhorn River
Neligh              11.0   12.0   14.0 :   6   <5   <5   <5   <5   <5
Norfolk             12.0   13.0   17.0 :  <5   <5   <5   <5   <5   <5
:North Fork Elkhorn River
Pierce              12.0   14.0   16.0 :  46   15   24   <5   <5   <5
:Elkhorn River
Pilger              12.0   15.0   17.0 :   6   <5   <5   <5   <5   <5
West Point          12.0   16.0   17.0 :   7   <5   <5   <5   <5   <5
Winslow             17.0   20.0   23.0 :  15    8   <5   <5   <5   <5
:Logan Creek
Uehling             18.0   19.0   21.0 :  <5   <5   <5   <5   <5   <5
:Maple Creek
Nickerson           11.5   13.0   17.0 :  12    8    6   <5   <5   <5
:Elkhorn River
Waterloo            14.0   18.0   21.0 :   8    8   <5   <5   <5   <5
:Platte River
Duncan               8.0    9.0   10.0 :   5    7   <5   <5   <5   <5
:Shell Creek
Columbus            20.0   21.0   22.0 :  26   28   21   22   <5   <5
:Platte River
North Bend           8.0   10.0   11.5 :  19   12   <5   <5   <5   <5
Leshara              8.0   10.0   12.0 :  24   19   <5   <5   <5   <5
Ashland             20.0   22.0   23.5 :  26   20   <5   <5   <5   <5
:Salt Creek
Roca                19.0   21.5   23.0 :   5    5   <5   <5   <5   <5
Lincoln (N 27th S   20.5   26.5   29.0 :   6    6   <5   <5   <5   <5
Greenwood           20.0   24.0   31.0 :  21   16    5    5   <5   <5
:Wahoo Creek
Ithaca              19.0   20.5   23.0 :  46   39   39   35   <5   <5
:Platte River
Louisville           9.0   11.0   12.0 :  20   16   <5   <5   <5   <5
:Big Blue River
Surprise             7.0   10.0   12.0 :  36   14    9   <5   <5   <5
:Lincoln Creek
Seward              15.0   17.0   20.0 :  62   29   36   12    8   <5
:Big Blue River
Seward              18.0   22.0   27.0 :  32   13   12   <5   <5   <5
:West Fork Big Blue River
Dorchester          15.0   22.0   24.4 :  36   35    5   <5   <5   <5
:Big Blue River
Crete               21.0   25.0   31.0 :  57   43   35   11    5   <5
:Turkey Creek
Wilber              12.5   16.0   21.0 :  44   33   12    5   <5   <5
:Big Blue River
Beatrice            18.0   26.0   32.0 :  37   30    7    5   <5   <5
Barneston           20.0   27.0   33.0 :  31   22   11   12   <5   <5
:Little Blue River
Fairbury            18.5   20.0   23.0 :  11    8    8    6   <5   <5
:Maple River
Mapleton            21.0   22.0   23.0 :   5    5    5    5   <5   <5
:Little Sioux River
Turin               25.0   28.0   34.5 :   9    8   <5    5   <5   <5
:Soldier River
Pisgah              28.0   29.0   30.0 :  <5   <5   <5   <5   <5   <5
:Boyer River
Logan               21.0   22.0   25.0 :  10    5    9    5    5    5
:Weeping Water Creek
Union               25.0   28.0   30.0 :   6   12   <5   <5   <5   <5
:East Nishnabotna River
Red Oak             18.0   22.0   27.0 :  41   33   14   17   <5    6
:West Nishnabotna River
Hancock             14.0   19.0   23.0 :  36   35   26   26    6    6
Randolph            19.0   22.0   27.0 :  38   40   16   11   <5   <5
:Nishnabotna River
Hamburg             25.0   27.5   33.0 :  49   45   12   15   <5   <5
:Little Nemaha River
Auburn              22.0   23.0   27.0 :  13   10   11    9   <5   <5
:North Fork Big Nemaha River
Humboldt            28.0   29.5   31.0 :  <5   <5   <5   <5   <5   <5
:Big Nemaha River
Falls City          27.0   30.0   36.0 :  13   10    5    5   <5   <5
:Nodaway River
Clarinda            23.0   26.0   29.0 :   8    7   <5   <5   <5   <5
:Missouri River
Decatur             35.0   38.0   41.0 :  32    9   17   <5    9   <5
Blair               26.5   28.2   33.0 :  48   19   34   10    8   <5
Omaha               29.0   32.0   40.0 :  43   15   20   <5   <5   <5
Nebraska City       18.0   23.0   27.0 :  93   45   39   11   <5   <5
Brownville          34.0   38.5   43.0 :  92   46   56   21   26    7
Rulo                17.0   21.0   26.0 :  92   47   61   26   13   <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: 02/15/2020  - 05/15/2020
Location              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:Niobrara River
Verdel                3.2    3.3    3.4    3.9    4.3    4.9    5.6
:Ponca Creek
Verdel                6.1    7.0    7.5    8.7   10.7   13.9   16.2
:Elkhorn River
Neligh                4.0    4.2    4.9    6.0    8.3   10.3   11.3
Norfolk               3.4    3.4    4.0    5.0    6.8    8.8   10.1
:North Fork Elkhorn River
Pierce                4.5    5.0    6.8   10.5   14.0   14.7   15.2
:Elkhorn River
Pilger                7.5    7.6    8.2    9.1   10.4   11.2   12.5
West Point            1.1    1.3    1.9    4.2    7.6   10.7   12.8
Winslow               9.6    9.7   10.4   13.2   15.1   17.3   19.0
:Logan Creek
Uehling               3.3    4.1    5.5    9.9   13.0   15.5   17.0
:Maple Creek
Nickerson             4.5    4.6    5.8    7.0    9.1   11.7   13.3
:Elkhorn River
Waterloo              3.6    4.3    5.3    8.4   11.6   13.8   15.5
:Platte River
Duncan                4.7    4.7    5.0    5.5    6.9    7.7    8.2
:Shell Creek
Columbus              1.5    1.5    3.3    9.2   20.4   21.7   21.8
:Platte River
North Bend            4.4    4.4    5.0    5.8    7.5    8.6    9.2
Leshara               4.8    4.9    6.0    6.7    8.0    8.8    9.4
Ashland              15.5   15.8   16.8   18.5   20.1   21.1   21.6
:Salt Creek
Roca                  2.2    2.7    5.3    7.7   15.2   18.2   19.1
Lincoln (N 27th S     3.1    3.6    6.1    9.3   15.1   17.9   21.9
Greenwood             3.0    3.9    6.8   11.4   19.4   21.7   23.7
:Wahoo Creek
Ithaca                6.4    6.4   10.8   18.2   21.6   22.2   22.6
:Platte River
Louisville            4.2    4.2    5.9    7.3    8.7    9.9   10.6
:Big Blue River
Surprise              1.7    2.0    3.3    4.3    7.9    9.7   10.6
:Lincoln Creek
Seward                7.5    7.8   13.1   15.9   18.1   19.8   20.6
:Big Blue River
Seward                3.4    3.6    9.9   14.6   19.9   22.3   22.8
:West Fork Big Blue River
Dorchester            3.7    3.7    9.0   12.9   17.9   19.7   22.1
:Big Blue River
Crete                10.2   12.4   19.2   22.3   26.0   27.6   30.6
:Turkey Creek
Wilber                2.6    4.1    8.0   11.7   14.7   16.2   16.7
:Big Blue River
Beatrice              4.5    6.1    9.7   13.2   22.2   24.9   27.3
Barneston             5.4    7.2    9.9   17.4   20.9   27.4   30.2
:Little Blue River
Fairbury              7.1    7.3   10.8   13.5   17.0   19.1   21.9
:Maple River
Mapleton              6.6    7.5    9.6   11.9   13.4   16.9   21.6
:Little Sioux River
Turin                12.9   13.5   15.0   18.8   21.5   24.6   26.5
:Soldier River
Pisgah                3.9    4.9    6.6    8.6   10.7   12.3   19.5
:Boyer River
Logan                 5.5    7.1    9.3   13.6   17.5   21.2   25.2
:Weeping Water Creek
Union                 4.3    5.5    7.9   10.6   16.8   23.6   25.7
:East Nishnabotna River
Red Oak               7.2    8.5   11.5   16.6   19.6   24.1   25.7
:West Nishnabotna River
Hancock               3.3    5.6    7.9    9.8   19.2   21.7   24.6
Randolph              8.6   10.5   14.1   17.1   21.3   22.5   24.7
:Nishnabotna River
Hamburg              11.7   13.7   18.4   25.0   26.2   27.6   29.5
:Little Nemaha River
Auburn                3.6    7.4   11.4   14.2   19.7   23.1   24.0
:North Fork Big Nemaha River
Humboldt              3.7    5.8    7.8   10.7   15.4   19.9   23.1
:Big Nemaha River
Falls City            6.9    9.8   15.2   19.8   25.2   28.4   30.2
:Nodaway River
Clarinda             11.5   12.1   13.5   15.6   19.5   22.4   24.0
:Missouri River
Decatur              29.2   29.3   30.6   32.0   35.8   40.2   43.8
Blair                21.3   21.7   23.2   25.7   28.9   32.2   35.2
Omaha                22.8   23.2   24.9   28.2   30.5   34.8   36.5
Nebraska City        17.0   19.2   20.1   22.4   24.7   25.6   26.1
Brownville           32.1   34.4   36.3   39.1   43.2   45.2   46.7
Rulo                 15.4   17.4   19.3   22.1   24.4   26.7   27.8

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: 02/15/2020  - 05/15/2020
Location              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:Niobrara River
Verdel                3.1    3.1    3.1    3.0    3.0    3.0    3.0
:Ponca Creek
Verdel                5.0    5.0    4.9    4.8    4.8    4.7    4.6
:Elkhorn River
Neligh                3.4    3.1    2.5    2.2    1.8    1.7    1.3
Norfolk               3.2    3.1    3.0    2.9    2.8    2.8    2.7
:North Fork Elkhorn River
Pierce                3.2    3.2    3.2    3.1    3.0    2.9    2.9
:Elkhorn River
Pilger                7.2    7.2    6.9    6.5    6.2    6.1    6.0
West Point            0.7    0.5    0.1    0.0    0.0    0.0    0.0
Winslow               9.2    9.1    8.8    8.6    8.4    8.3    8.3
:Logan Creek
Uehling               3.1    2.9    2.5    2.2    2.1    2.1    2.1
:Maple Creek
Nickerson             1.0    1.0    1.0    1.0    1.0    1.0    1.0
:Platte River
Duncan                4.2    4.2    4.1    4.0    4.0    3.9    3.8
:Platte River
North Bend            3.2    3.0    2.5    2.4    2.3    2.2    2.1
Leshara               4.1    4.0    3.9    3.8    3.7    3.6    3.5
Ashland              14.9   14.8   14.7   14.5   14.4   14.3   14.3
:Salt Creek
Roca                  2.0    1.9    1.8    1.8    1.7    1.7    1.7
Lincoln (N 27th S     2.8    2.6    2.5    2.5    2.4    2.4    2.4
Greenwood             2.7    2.5    2.5    2.4    2.3    2.3    2.3
:Wahoo Creek
Ithaca                4.0    4.0    3.5    3.0    2.9    2.9    2.9
:Platte River
Louisville            3.7    3.4    3.0    2.6    2.5    2.4    2.3
:Big Blue River
Surprise              1.5    1.5    1.5    1.5    1.4    1.4    1.4
:Lincoln Creek
Seward                5.2    5.2    5.2    5.1    5.1    5.1    5.1
:Big Blue River
Seward                2.3    2.1    2.1    2.1    2.1    2.1    2.1
:West Fork Big Blue River
Dorchester            3.5    3.4    3.3    3.3    3.2    3.2    3.2
:Big Blue River
Crete                 9.0    8.9    8.8    8.8    8.7    8.6    8.6
:Turkey Creek
Wilber                2.6    2.5    2.5    2.5    2.2    2.0    1.9
:Big Blue River
Beatrice              4.0    3.9    3.8    3.8    3.7    3.7    3.7
Barneston             4.4    4.3    4.2    4.2    4.1    4.1    4.1
:Little Blue River
Fairbury              6.4    6.4    6.4    6.3    6.2    6.2    6.2
:Maple River
Mapleton              4.8    4.8    4.8    4.8    4.8    4.8    4.7
:Little Sioux River
Turin                 8.1    8.1    8.1    8.1    8.1    8.0    8.0
:Soldier River
Pisgah                3.2    3.2    3.2    3.1    3.1    3.0    3.0
:Boyer River
Logan                 3.3    3.3    3.3    3.3    3.2    3.1    3.1
:Weeping Water Creek
Union                 3.6    3.5    3.2    3.0    2.8    2.8    2.8
:East Nishnabotna River
Red Oak               5.5    5.5    5.4    5.4    4.7    2.8    2.0
:West Nishnabotna River
Hancock               1.2    1.2    1.2    1.2    1.2    1.2    1.2
Randolph              7.4    7.3    7.3    7.2    6.6    6.6    6.6
:Nishnabotna River
Hamburg              10.3   10.2    9.8    9.6    9.0    8.6    8.4
:Little Nemaha River
Auburn                1.5    1.5    1.5    1.5    1.5    1.5    1.5
:North Fork Big Nemaha River
Humboldt              2.2    2.1    2.1    2.0    1.9    1.9    1.8
:Big Nemaha River
Falls City            4.5    4.5    4.4    4.3    4.2    4.2    4.1
:Nodaway River
Clarinda             10.7   10.7   10.7   10.7   10.7   10.7   10.7
:Missouri River
Decatur              23.5   23.4   23.4   23.4   23.4   23.2   23.1
Blair                15.5   15.4   15.4   15.4   15.3   15.2   15.1
Omaha                15.8   15.8   15.7   15.6   15.6   15.4   15.3
Nebraska City        12.5   12.4   12.3   12.3   12.3   12.2   12.2
Brownville           27.3   27.2   27.1   27.1   27.1   26.9   26.8
Rulo                 10.8   10.7   10.6   10.5   10.5   10.4   10.3

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/oax for more weather and water
information.

$$






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