Flood Potential Outlook
Issued by NWS Jackson, KY

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FGUS73 KJKL 152207
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PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE JACKSON KY
507 PM EST THU FEB 15 2018

...Spring Flood and Water Resources Outlook Number 1...

This outlook covers eastern Kentucky.

The flood risk is above normal for this time of year. Minor flooding
is expected due to rainfall.

This outlook is valid through April 2018. 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:  02/20/2018 - 05/21/2018

                                       :    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
--------           -----  -----  ----- : ---  ---  ---  ---  ---  ---
:Cumberland River
Barbourville        27.0   33.0   38.0 :  61   64   36   41   20   24
Pineville         1002.0 1010.0 1019.0 :  33   45   13   22   <5   10
Williamsburg        21.0   27.5   32.0 :  70   71   37   38   20   21
Baxter              16.0   18.0   20.0 :  24   35   17   22   11   16
:Kentucky River
Heidelberg          20.0   24.0   30.0 :  52   52   17   18   <5   <5
Ravenna             21.0   25.0   31.0 :  70   71   48   47   31   31
:Levisa Fork Big Sandy River
Pikeville           35.0   42.0   50.0 :  12   18   <5   <5   <5   <5
Prestonsburg        40.0   43.0   46.0 :  <5   <5   <5   <5   <5   <5
Paintsville         35.0   38.0   42.0 :  13   22    8   13   <5    5
:North Fork Kentucky River
Hazard              20.0   27.0   33.0 :  31   18   13   <5   <5   <5
Jackson             29.0   31.0   40.0 :  31   33   26   27    8    8
:Cumberland River
Cumberland          12.0   14.0   16.0 :  <5   <5   <5   <5   <5   <5
:Red River
Clay City           17.0   19.0   23.0 :  36   36   24   23    9    9
:Russell Fork Big Sandy River
Elkhorn City        21.0   22.0   24.0 :  <5   <5   <5   <5   <5   <5
:South Fork Kentucky River
Booneville          27.0   32.0   38.0 :  52   47   27   28   17   14
Oneida              29.0   34.0   38.0 :  20   20    7    7   <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: 02/20/2018 - 05/21/2018
Location              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:Cumberland River
Barbourville         11.9   14.9   23.1   30.2   35.3   44.2   49.3
Pineville           982.3  983.9  989.4  998.2 1003.9 1011.8 1018.7
Williamsburg         12.7   14.9   20.1   24.9   30.0   35.8   37.4
Baxter                4.1    6.5    9.0   12.2   15.6   20.3   25.3
:Kentucky River
Heidelberg           16.6   17.2   18.3   20.1   22.8   25.1   26.8
Ravenna              18.1   18.7   20.2   24.1   33.3   39.0   45.1
:Levisa Fork Big Sandy River
Pikeville            12.5   13.2   15.8   24.2   30.6   35.8   37.5
Prestonsburg         10.7   12.4   16.6   24.4   32.3   36.3   38.7
Paintsville          11.0   12.5   16.8   21.7   30.3   36.4   41.4
:North Fork Kentucky River
Hazard                6.3    7.0    9.6   14.2   21.6   28.1   30.5
Jackson               7.7   10.7   12.8   22.3   31.2   38.1   42.6
:Cumberland River
Cumberland            5.0    6.1    7.5    8.9    9.7   10.9   11.8
:Red River
Clay City             8.1    9.6   11.9   14.8   18.7   22.6   24.3
:Russell Fork Big Sandy River
Elkhorn City          9.2    9.4   10.1   12.3   14.8   17.6   19.3
:South Fork Kentucky River
Booneville           13.2   14.7   18.8   27.8   32.4   42.3   44.8
Oneida               13.6   14.6   17.1   21.4   26.8   32.9   34.9

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: 02/20/2018 - 05/21/2018
Location              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:Cumberland River
Barbourville          3.0    2.8    2.5    2.3    2.1    2.0    2.0
Pineville           977.7  977.5  977.2  976.9  976.8  976.7  976.7
Williamsburg          4.8    4.6    4.0    3.6    3.4    3.4    3.3
Baxter                2.0    1.9    1.6    1.5    1.4    1.4    1.4
:Kentucky River
Heidelberg           10.3   10.1    9.9    9.5    9.4    9.3    9.2
Ravenna              11.5   11.3   11.0   10.6   10.5   10.3   10.3
:Levisa Fork Big Sandy River
Pikeville             7.6    7.1    6.8    6.7    6.4    6.3    6.2
Prestonsburg          3.9    3.6    2.9    2.6    2.3    2.0    1.9
Paintsville           5.3    4.8    4.1    3.8    3.4    3.0    2.8
:North Fork Kentucky River
Hazard                4.5    4.4    4.3    4.2    4.1    4.1    4.0
Jackson               2.2    2.1    1.9    1.6    1.5    1.4    1.4
:Cumberland River
Cumberland            3.8    3.8    3.7    3.6    3.6    3.5    3.5
:Red River
Clay City             3.3    3.0    2.7    2.5    2.4    2.3    2.3
:Russell Fork Big Sandy River
Elkhorn City          7.1    6.8    6.8    6.6    6.5    6.4    6.3
:South Fork Kentucky River
Booneville            4.7    4.6    4.2    4.0    3.9    3.7    3.6
Oneida                8.1    7.9    7.5    7.3    7.1    6.9    6.6

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.

This outlook calls for above normal chances of minor flooding due to
the current streamflow conditions and expected precipitation over
the next few weeks. Minor flooding means minimal or no property
damage, but possibly some public threat or inconvenience.

Ice jams and snow melt are usually not a factor for flooding in this
part of the country.

Precipitation so far through the middle of February across most of
eastern Kentucky has averaged between 2 and 4 inches above normal.
Temperatures have averaged near normal so far for the month. Soil
moisture was slightly above normal, and streamflows as of mid
February were running above to well above normal. Reservoir levels
area also above normal.

Multiple weather systems will result in 2 to 3 inches of rain across
the region over the next week.

The 6 to 10 outlook, which runs from February 21st to February 25th,
and the 8 to 14 day outlook, which runs from February 23rd to March
1st, both call for above normal temperatures and precipitation. At
this time of the year, normal average temperatures are in the low
40s and precipitation averages between a half and three quarters
of an inch.

The outlook for March calls for near to slightly above normal
precipitation and equal chances for near, above, or below normal
temperatures. Normal precipitation for March is between four and
five inches. The seasonal outlook for March through May also calls
for above normal precipitation.

Additional supportive data and explanations are available for
precipitation and temperature outlooks as well as soil moisture at
www.cpc.noaa.gov.

Current snowpack data are available at www.nohrsc.noaa.gov/nsa.

Current streamflow data are available at water.usgs.gov/waterwatch.

Visit our web site weather.gov/jkl for more weather and water
information.

The next spring and water resources outlook will be issued on March
1st.

$$

Geogerian



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