Flood Potential Outlook
Issued by NWS Dodge City, KS

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PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE DODGE CITY KS
300 PM CST THU FEB 15 2018

...Spring Flood and Water Resources Outlook Number 2...

This outlook applies to the Dodge City Hydrologic Service Area (HSA)
which includes the following rivers in southwest Kansas...

  - The Arkansas River from the Kansas-Colorado state line to below
    Larned, Kansas
  - the Saline and Smoky Hill Rivers in Trego and Ellis counties
  - the Walnut Creek in Ness and Rush counties
  - the Pawnee Creek and Buckner Creek
  - the Rattlesnake Creek and Crooked Creek
  - the Cimarron River and Medicine Lodge River

This outlook is valid from March 1 through March 15, 2018

Outlooks are routinely issued in February and March to give
advanced notice of possible flooding. They are based on soil
moisture, snowpack magnitude and streamflow at the time the outlook
is issued. The vast majority of flood events in the Dodge City
Service area result from short periods of higher intensity
precipitation...or longer periods of excessive precipitation.

Over the past three months, average precipitation across central and
southwest Kansas has been around 1 to 2.5 inches below normal.

Over the past year, locations from Ashland to Medicine Lodge and St
John received total precipitation amounts that were as much as 6
inches below normal. Parts of far southwest Kansas west of Highway 83
saw above normal yearly precipitation totals by as much as 3 to 6
inches. A portion of this area from Ulysses to Hugoton and Elkhart
saw yearly precipitation amounts as much as 9 to 12 inches above
normal.

Soil moisture was near normal across southwest Kansas. Only parts of
south central Kansas along Highway 281 saw a deficit, running in the
30th percentile.

The latest U.S. Drought Monitor Index (www.droughtmonitor.unl.edu)
issued February 22, 2018 shows slowly worsening drought conditions
across central and western Kansas. Abnormally Dry (D0) conditions
exist along I-70 while farther south, Extreme Drought (D3) conditions
had developed along and south of Highway 56 from Elkhart to Larned.
Parts of south central Kansas from St John to Medicine Lodge were in
Severe Drought (D2) conditions.

The Climate Prediction Center`s (CPC) U.S. Seasonal Drought Outlook
valid through May 2018 is calling for drought conditions to persist
over all of central and southwest Kansas.

The Climate Prediction Center (CPC) Outlook for the three month
period from March through May 2018 calls for better chances for below
normal precipitation and above normal temperatures.

The eight to fourteen day climate outlooks from CPC are forecasting
near normal temperatures and below normal precipitation.

Colorado Rocky Mountain winter snowpack in the Upper Arkansas River
Basin is below long term average conditions. The average snowpack
from USDA SNOTEL sites in the upper part of the basin is roughly at
63 percent of average.

At John Martin Reservoir in southeast Colorado, current water surface
elevation is at 3849.19 feet which equates to storage of
approximately 310,303 acre-feet. The water surface elevation is
approximately 2.68 feet below the top of the conservation pool. The
conservation pool is approximately 91 percent filled so there is
ample reservoir storage for any potential snowmelt runoff.

At Cedar Bluff Reservoir in west central Kansas, the reservoir pool
elevation stands at 2117.6 feet or approximately 26.4 feet below the
top of the conservation pool and 48.4 feet from the top of the flood
pool which means there is abundant capacity for spring rains.

The U.S. Geological Survey 28-day average streamflow conditions map
shows that flows in many area rivers and streams in the Dodge City
service area are below to much below normal. The exceptions are on
the on parts of the Smoky Hill, Pawnee and Arkansas River downstream
of the Colorado border where near normal flow is occurring.

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:  03/03/2018  - 06/01/2018

                                       :    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
--------           -----  -----  ----- : ---  ---  ---  ---  ---  ---
:Smoky Hill River
Arnold 12N           7.0    9.0   11.0 :  <5   <5   <5   <5   <5   <5
Schoenchen 2E       11.0   14.0   17.0 :  <5    6   <5   <5   <5   <5
:Big Creek
Ellis               15.0   17.0   19.0 :  <5   <5   <5   <5   <5   <5
Hays 2SSE           26.0   29.0   32.0 :  <5   <5   <5   <5   <5   <5
:Saline River
Wakeeney 5N         13.0   15.0   17.0 :  <5   <5   <5   <5   <5   <5
:Arkansas River
Coolidge             8.0   10.0   12.0 :   6   <5   <5   <5   <5   <5
Syracuse 1S         10.0   12.0   14.0 :  <5   <5   <5   <5   <5   <5
Garden City         10.0   13.0   16.0 :  <5   <5   <5   <5   <5   <5
Dodge City          11.0   13.0   15.0 :  <5   <5   <5   <5   <5   <5
:Walnut Creek
NEKOMA              29.0   31.0   33.0 :  <5   <5   <5   <5   <5   <5
:Buckner Creek
Burdett 7W          16.0   21.0   25.0 :  <5   <5   <5   <5   <5   <5
:Pawnee Creek
Burdett 7WNW        30.0   32.0   34.0 :  <5   <5   <5   <5   <5   <5
:Pawnee River
Sanford             24.0   27.0   30.0 :  <5   <5   <5   <5   <5   <5
:Rattlesnake Creek
Macksville 8SE       9.0   10.0   11.0 :  <5   <5   <5   <5   <5   <5
Zenith 10NNW        17.0   18.0   19.0 :   5    5   <5   <5   <5   <5
:Crooked Creek
Englewood            6.5    8.0   10.0 :  16   11    7   <5   <5   <5
:Cimarron River
Forgan 8NNE          5.0    6.0    7.0 :   8   <5   <5   <5   <5   <5
:Medicine Lodge River
Kiowa 2NE           10.0   12.0   13.0 :  <5   <5   <5   <5   <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: 03/03/2018  - 06/01/2018
Location              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:Smoky Hill River
Arnold 12N            0.3    0.5    0.6    2.5    4.5    5.4    6.2
Schoenchen 2E         1.0    1.0    1.0    3.2    5.0    6.8    7.7
:Big Creek
Ellis                 9.5    9.5    9.5    9.5   10.7   12.7   13.0
Hays 2SSE             5.1    5.1    5.1    5.8    9.7   14.6   21.1
:Saline River
Wakeeney 5N           2.6    2.6    2.7    2.8    6.5   10.2   11.6
:Arkansas River
Coolidge              3.3    3.3    3.4    3.5    3.9    6.9    8.7
Syracuse 1S           4.6    4.6    4.7    4.8    5.3    7.7    9.3
Garden City           6.2    6.2    6.2    6.2    6.6    7.0    7.6
Dodge City            6.0    6.0    6.0    6.0    6.0    8.2    8.9
:Walnut Creek
NEKOMA                7.3    7.3    7.3   11.2   18.3   23.5   26.4
:Buckner Creek
Burdett 7W            4.8    4.8    4.8    4.8    8.0   10.8   14.1
:Pawnee Creek
Burdett 7WNW          2.6    2.6    2.6    3.9   10.6   14.3   16.6
:Pawnee River
Sanford               5.7    5.7    5.7    6.7   10.0   12.8   14.5
:Rattlesnake Creek
Macksville 8SE        3.3    3.3    3.3    4.1    5.7    6.9    7.6
Zenith 10NNW         12.0   12.0   12.0   13.0   14.1   15.8   17.1
:Crooked Creek
Englewood             3.2    3.3    3.4    3.8    5.4    7.4    8.9
:Cimarron River
Forgan 8NNE           2.5    2.8    3.1    3.5    4.1    4.8    5.6
:Medicine Lodge River
Kiowa 2NE             0.8    0.8    1.1    3.1    5.0    6.9    8.7

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: 03/03/2018  - 06/01/2018
Location              95%    90%    75%    50%    25%    10%     5%
--------            ------ ------ ------ ------ ------ ------ ------
:Smoky Hill River
Arnold 12N            0.0    0.0    0.0    0.0    0.0    0.0    0.0
Schoenchen 2E         1.0    1.0    1.0    1.0    1.0    1.0    1.0
:Big Creek
Ellis                 9.5    9.4    9.4    9.4    9.4    9.4    9.4
Hays 2SSE             5.1    5.1    5.0    4.9    4.8    4.8    4.8
:Saline River
Wakeeney 5N           2.5    2.4    2.3    0.5    0.5    0.5    0.5

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/ddc for more weather and water
information.

Based on the above information, there is a below normal risk of
spring flooding across the Dodge City Service Area.

This will be the last Spring Flood and Water Resources Outlook issued
this year.

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

$$

GERARD








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