Flood Potential Outlook
Issued by NWS Grand Junction, CO

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COC007-029-033-037-045-051-053-067-077-081-083-085-091-097-103-
107-111-113-UTC009-019-037-047-302015-

Water Supply Outlook
National Weather Service Grand Junction CO
250 PM MST Thu Mar 1 2018


...SPRING FLOOD AND WATER RESOURCES OUTLOOK FOR WESTERN COLORADO AND
EASTERN UTAH...

...Spring Flood and water resources outlook for western Colorado
and eastern Utah number 2...

This is the second 2018 spring runoff outlook for western Colorado
and eastern Utah covering all or portions of the Yampa/White...Upper
Colorado...Duchesne...Green...Gunnison...Dolores and San Juan River
Basins.

The potential for spring 2018 flooding due to snowmelt is considered
lower than normal in the Yampa/White, Upper Colorado mainstem, with
well below normal potential for the Gunnison, Dolores and San Juan
Basins of Colorado. For eastern Utah including the Duchesne River
Basin the flood potential is lower than normal and for the Green
River Basin the potential is considered not high.

Hydrologic models are currently forecasting below average to well
below average flows across western Colorado and eastern Utah during
the snowmelt runoff period. 50% exceedance forecasts for many sites
are projected to be below to well below average. The Gunnison,
Dolores and San Juan Basins have the lowest projected volumes with
the Yampa, White and Upper Colorado River Basins are below average
but better than the southern basins. Early indications are that
March forecast for runoff volumes will trend just slightly upward
for the Upper Green River with the Duchesne trending downward by 10
to 15 percent. Basins in southeast Utah showed little change. In
Colorado March forecasts are showing minimal change for the
Gunnison, San Miguel, Dolores and lower San Juan Basins. The eastern
part of the San Juan Basin is trending up slightly with the western
part of the basin trending down. For the Upper Colorado River Basin
minimal change to just slightly higher volumes.

Spring temperatures affect the pattern of snowmelt runoff and
consequently the magnitude of peak flows. In normal
years...additional snowpack can accumulate in the mountains
through April. Heavy rainfall or unseasonably warm temperatures
during the snowmelt season can affect total runoff volume and peak
flow increasing the threat of flooding.


Observed Precipitation
----------------------

The water year started out dry for most locations in eastern Utah
and western Colorado. This dry pattern remained dominate through
the beginning of the winter and into January. The precipitation for
January ranged between 60 and 85 percent of normal. As of January
31, 2018 the SWE (snow water equivalent) ranged from 37 percent to
75 percent of normal. For eastern Utah that range was from 38
percent south to 87 percent north.

By February 28, 2018 the SWE values had increased ranging from 53
percent to 83 percent in western Colorado. Over eastern Utah values
decrease north to 81 percent and increased south to 51 percent.

Extreme drought D3 is over a portion of southeastern Utah and
southwestern Colorado with severe drought D2 is over much of the
rest of eastern Utah and western Colorado with the exception of the
far northern basins.

Observed Snowpack
-----------------
Snowpack on the Grand Mesa continues to be one of
the lowest of all the years on record. Current SWE values are near
2002 levels and slightly above 1977 levels.

Basin snowpack conditions...percent of median...for the period
October 1 2017 to March 1 2018:
-----------------------------------
In western Colorado...

Basin                   Snow Water
                        Equivalent
-----                   ----------
Yampa/White                 81
Far Upper Colorado hdwrs    90
Roaring Fork                80
Gunnison                    63
Dolores/San Miguel          56
San Juan                    59
Animas                      55

In eastern Utah...

Basin                   Snow Water
                        Equivalent
-----                   ----------
Upper Green                 52
Duchesne                    54
Southeastern Utah          108
----------------------------------

Basin Conditions (% Of Average) As Of February 27:
   *NOTE: Snow Is % Of Median

 Subbasin                  Jan    Oct-Jan  Feb
                          Precip  Precip   Snow
----------------------    ------  -------  ----
   Upper Colorado           85     70      85
   Gunnison                 75     45      65
   Dolores/San Miguel       75     45      60
   San Juan                 60     35      60
   Yampa/White              75     70      75



Reservoir Storage (KAF) As Of January 31:
                            C U R R E N T   Y R         1981-2010
                             Eom      % Of     % Of       Jan 31 Usable
                          Storage  Average  Capacity  avg Storage   Capacity
---------------------------------------------------------------------------
   Colorado - Lake Granb|    491.4|    140|    100||  352.2|     490.3|
   Willow Ck - Willow Ck|      7.8|     98|     86||    8.0|       9.1|
   Williams Fork - Willi|     66.0|    103|     68||   63.8|      96.9|
   Muddy Ck - Wolford Mo|     54.5|    122|     83||   44.6|      66.0|
   Blue - Dillon Res    |    240.1|    108|     95||  223.2|     254.0|
   Blue - Green Mtn Res |     70.5|     87|     48||   81.1|     146.9|
   Homestake Ck - Homest|  -9999.0|    -99|    -99||   31.9|      43.0|
   Frying Pan - Ruedi Re|     69.4|     96|     68||   72.4|     102.0|
   Plateau Ck - Vega Res|     11.0|     87|     33||   12.6|      32.9|
   Taylor - Taylor Park |     74.2|    111|     70||   66.9|     106.2|
   Gunnison - Blue Mesa |    554.5|    108|     67||  514.6|     829.5|
   Gunnison - Morrow Poi|    109.3|     98|     93||  111.4|     117.0|
   Gunnison - Crystal Re|     15.5|    101|     88||   15.3|      17.5|
   Muddy Ck - Paonia Res|      2.9|     68|     17||    4.2|      16.7|
   Uncompahgre - Ridgway|     60.9|     88|     73||   69.2|      83.0|
   Dolores - Mcphee Res |    284.5|    105|     75||  270.9|     381.1|
   Los Pinos - Vallecito|     67.3|    106|     54||   63.5|     125.4|
   San Juan - Navajo Res|   1254.9|     96|     74|| 1310.4|    1696.0|
   Florida - Lemon Res, |     18.6|     89|     47||   20.9|      39.8|
   Colorado - Lake Powel|  13672.3|     79|     56||17338.2|   24322.0|



Streamflow Forecasts:
Developed:                    Feb 27 2018
Volume in 1000 acre-feet


Most Recent April-July Runoff Forecasts:

Yampa/White Basins
                           Period     50%  %AVG    10%    30%    70%    90%    AVG
                           ------    ----  ----   ----   ----   ----   ----    ---
Yampa River
  Stagecoach Rsvr, abv     Apr-Jul   14.5    63   18.2   15.0   13.0    9.0     23
  Steamboat Springs        Apr-Jul    174    67    255    199    142    101    260
Elk River
  Milner, nr               Apr-Jul    245    77    330    275    200    158    320
Elkhead Ck
  Long Gulch, abv, Hayden  Apr-Jul     41    56     60     48     32     21     73
Yampa River
  Maybell, nr              Apr-Jul    595    64    860    680    470    350    935
Little Snake River
  Slater, nr               Apr-Jul     95    61    148    116     80     58    156
  Dixon, nr                Apr-Jul    180    52    305    230    154    114    345
  Lily, nr                 Apr-Jul    185    54    315    245    153     99    345
Yampa River
  Deerlodge Park           Apr-Jul    790    64   1150    900    610    440   1240
White River
  Meeker, nr               Apr-Jul    155    55    230    180    135    115    280
  Watson, nr               Apr-Jul    158    56    245    186    138    117    280

Upper Colorado, Above Gunnison Basin
                           Period     50%  %AVG    10%    30%    70%    90%    AVG
                           ------    ----  ----   ----   ----   ----   ----    ---
Colorado River
  Lake Granby, Granby, nr  Apr-Jul    180    82    280    210    150    124    220
Willow Ck
  Willow Ck Res, Granby,   Apr-Jul     40    85     70     52     29     21     47
Fraser River
  Winter Park              Apr-Jul   17.5    90     23     20   15.0   12.0   19.4
Williams Fork River
  Williams Fork Res, Pars  Apr-Jul     80    83    114     90     70     56     96
Blue River
  Dillon Res               Apr-Jul    140    86    188    160    120     94    163
  Green Mtn Res            Apr-Jul    230    84    315    260    195    150    275
Muddy Ck
  Wolford Mountain Reserv  Apr-Jul     33    61     54     42   24.0   16.0     54
Colorado River
  Kremmling, nr            Apr-Jul    680    79   1050    790    580    455    860
Eagle River
  Gypsum, blo              Apr-Jul    220    66    335    190    250    146    335
Colorado River
  Dotsero, nr              Apr-Jul   1030    74   1550    880   1200    680   1400
Frying Pan River
  Ruedi Res, Basalt, nr    Apr-Jul     93    67    140     80    105     61    139
Roaring Fork River
  Glenwood Springs         Apr-Jul    450    65    670    400    500    320    690
Colorado River
  Glenwood Springs, blo    Apr-Jul   1510    72   2270   1350   1700   1030   2110
  Cameo, nr                Apr-Jul   1620    69   2450   1400   1800   1110   2360
Plateau Ck
  Cameo, nr                Apr-Jul     45    36     90     33   60.0   18.0    124

Gunnison Basin
                           Period     50%  %AVG    10%    30%    70%    90%    AVG
                           ------    ----  ----   ----   ----   ----   ----    ---
Taylor River
  Taylor Park Res          Apr-Jul     70    71     90     78     56     45     99
  Almont                   Apr-Jul    104    67    135    118     85     65    155
East River
  Almont                   Apr-Jul    109    60    160    130     88     70    182
Gunnison River
  Gunnison, nr             Apr-Jul    225    61    320    270    175    135    370
Tomichi Ck
  Gunnison                 Apr-Jul     36    49     71     50     28     20     74
Lake Fork River
  Gateview                 Apr-Jul     74    60    109     91     55     45    123
Gunnison River
  Blue Mesa Res            Apr-Jul    400    59    600    480    290    230    675
  Morrow Point Res         Apr-Jul    435    59    635    475    325    265    740
  Crystal Res              Apr-Jul    480    57    680    520    370    310    835
Muddy Ck
  Paonia Res, Bardine, nr  Mar-Jun     35    36     69     48   24.0   18.0     96
  Paonia Res, Bardine, nr  Apr-Jul     34    35     68     47   23.0   17.0     97
NF Gunnison River
  Somerset, nr             Apr-Jul    135    46    235    160    105     85    295
Surface Ck
  Cedaredge                Apr-Jul    4.5    27    9.0    6.0    3.0    2.5   16.8
Uncompahgre River
  Ridgway Res              Apr-Jul     56    55     87     68     43     35    101
  Colona                   Apr-Jul     62    45    110     83     49     37    137
  Delta                    Apr-Jul     35    31     80     54   27.0   19.0    113
Gunnison River
  Grand Junction, nr       Apr-Jul    725    49   1180    900    600    500   1480

Dolores Basin
                           Period     50%  %AVG    10%    30%    70%    90%    AVG
                           ------    ----  ----   ----   ----   ----   ----    ---
Dolores River
  Dolores                  Apr-Jul    100    41    186    140     83     60    245
  Mcphee Res               Apr-Jul    110    37    200    155     86     61    295
San Miguel River
  Placerville, nr          Apr-Jul     64    50     95     77     52     38    128
Dolores River
  Cisco, nr                Apr-Jul    155    27    270    195    120     86    565

Upper Colorado, Confluence
                           Period     50%  %AVG    10%    30%    70%    90%    AVG
                           ------    ----  ----   ----   ----   ----   ----    ---
Colorado River
  Cisco, nr                Apr-Jul   2410    54   3800   2000   2800   1650   4440

San Juan Basin
                           Period     50%  %AVG    10%    30%    70%    90%    AVG
                           ------    ----  ----   ----   ----   ----   ----    ---
San Juan River
  Pagosa Springs           Apr-Jul    100    47    160    125     75     50    215
  Carracas, nr             Apr-Jul    175    46    275    215    130    100    380
Rio Blanco River
  Pagosa Springs, nr, Bla  Apr-Jul     30    56     45     36   22.0   15.0     54
Navajo River
  Chromo, nr, Oso Div Dam  Apr-Jul     35    54     52     42   24.0   19.0     65
Piedra River
  Arboles, nr              Apr-Jul     77    37    140     95     52     40    210
Los Pinos River
  Vallecito Res, Bayfield  Apr-Jul     75    39    130     95     55     38    194
San Juan River
  Navajo Res, Archuleta,   Apr-Jul    260    35    500    340    180    120    735
Florida River
  Lemon Res, Durango, nr   Apr-Jul   18.0    33     35     25   12.0    9.0     55
Animas River
  Durango                  Apr-Jul    165    40    250    195    120     90    415
San Juan River
  Farmington               Apr-Jul    370    34    630    470    300    215   1100
La Plata River
  Hesperus                 Apr-Jul    7.0    30   13.0   10.0    4.5    3.0     23
San Juan River
  Bluff, nr                Apr-Jul    340    31    610    425    270    190   1100
Mancos River
  Mancos, nr               Apr-Jul   10.0    32     20     14    7.0    5.0     31

Eastern Utah - Green River Basin

                           Period     50%  %AVG    10%    30%    70%    90%    AVG
                           ------    ----  ----   ----   ----   ----   ----    ---
Blacks Fork River
  Robertson, nr            Apr-Jul     70    79    112     84     61     49     89
Green River
  Flaming Gorge Res, Flam  Apr-Jul    890    91   1470   1030    780    600    980
White River
  Watson, nr               Apr-Jul    158    56    245    186    138    117    280
Big Brush Ck
  Vernal, nr, Red Fleet R  Apr-Jul   12.9    61     22     16   11.4    8.0     21
Ashley Ck
  Vernal, nr               Apr-Jul     29    58     55     33   21.0   16.7     50
Whiterocks River
  Whiterocks, nr           Apr-Jul     33    61     58     38   27.0   19.8     54
Uinta River
  Neola, nr                Apr-Jul     50    68     80     58     41     27     74
Duchesne River
  Myton                    Apr-Jul    150    45    315    197    113     80    330
  Randlett, nr             Apr-Jul    154    40    340    205    119     88    385
Fish Ck
  Scofield, nr, Reservoir  Apr-Jul   10.7    36     24     16    8.6    6.3     30
Price River
  Scofield Res, Scofield,  Apr-Jul   14.0    34     32     21   11.6    8.5     41
White River
  Blo Tabbyune Ck, Soldie  Apr-Jul    4.9    32    9.9    6.7   3.60   1.71   15.5
Green River
  Green River, Ut          Apr-Jul   1920    65   3270   2290   1620   1300   2960

Lake Powell
                           Period     50%  %AVG    10%    30%    70%    90%    AVG
                           ------    ----  ----   ----   ----   ----   ----    ---
Colorado River
  Lake Powell, Glen Cyn D  Apr-Jul   3400    47   6200   4200   2750   1950   7160

50% Most probable volume in 1000 acre-feet.
%AVG  Most probable volume in percent of the 1981-2010 average.
10% Volume that has a 10 percent chance of being exceeded.
30% Volume that has a 30 percent chance of being exceeded.
90% Volume that has a 90 percent chance of being exceeded.
70% Volume that has a 70 percent chance of being exceeded.
AVG   Average volume for the 1981-2010 period.

All forecast volumes reflect natural flow.  Actual observed flow may
be affected by upstream water management.

Expect an updated forecast by Mar 6, 2018.

Climate Outlook
---------------

The Climate Prediction Center outlook for the three month period
of March through May 2018 indicates a chance of higher
than normal temperatures and equal chances of either above, below or
normal precipitation along the Wyoming border with the rest of
eastern Utah and western Colorado having a higher chance of below
normal precipitation.

It should be emphasized that snow accumulation and conditions could
change before the runoff begins.

Changing hydrometeorological conditions can have a significant
impact on water supply forecasts. Additional products will be
issued as conditions evolve.

Additional information is available at weather.gov/gjt.
For detailed flow forecasts visit www.cbrfc.noaa.gov

Data from the Natural Resources Conservation Service...the
Colorado Basin River Forecast Center...and the Climate Prediction
Center were used to produce this product.


$$

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