Green Water Supply Outlook, February 1, 2018

Note: This publication is scheduled for revision. If you have feedback on content, format, or publication frequency, please contact us.
Prepared by Ashley Nielson
NOAA, National Weather Service
Colorado Basin River Forecast Center
Salt Lake City, Utah
www.cbrfc.noaa.gov

Contents

Green Summary




*Median of forecasts within each basin.


Upper Green Basin Conditions




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Yampa/White Basin Conditions




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Duchesne Basin Conditions




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Lower Green Basin Conditions




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.


Upper Green Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		70%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		30%
Exceedance
Volume		10%
Exceedance
Volume
Green
Daniel, Nr, Warren Bridge, At April-July205 240 275 112 300 360
Pine Ck
Fremont Lk, Abv April-July77 88 100 102 104 121
New Fork
Big Piney, Nr April-July250 305 355 100 405 485
Green
Fontenelle Res, Fontenelle Nr April-July530 670 750 103 870 1100
Big Sandy
Farson, Nr April-July34 45 50 96 57 73
Green
Green River, Wy, Nr April-July540 680 750 103 885 1120
Hams Fork
Frontier, Nr, Pole Ck, Blo April-July24 29 36 67 44 64
Viva Naughton Res April-July28 35 45 61 56 90
Blacks Fork
Robertson, Nr April-July49 61 70 79 84 112
Ef Smiths Fork
Stateline Res, Robertson,nr April-July15.7 18.2 21 81 25 31
Green
Flaming Gorge Res, Flaming Gorge Dam, At April-July600 780 890 91 1030 1470


Yampa/White Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		70%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		30%
Exceedance
Volume		10%
Exceedance
Volume
Yampa
Stagecoach Rsvr, Abv April-July9 13 14.5 63 15 18.2
Steamboat Springs April-July101 142 174 67 199 255
Elk
Milner, Nr April-July158 200 245 77 275 330
Elkhead Ck
Long Gulch, Abv, Hayden, Nr April-July21 32 41 56 48 60
Yampa
Maybell, Nr April-July350 470 595 64 680 860
Little Snake
Slater, Nr April-July58 80 95 61 116 148
Dixon, Nr April-July114 154 180 52 230 305
Lily, Nr April-July99 153 185 54 245 315
Yampa
Deerlodge Park April-July440 610 790 64 900 1150
White
Meeker, Nr April-July115 135 155 55 180 230
Watson, Nr April-July117 138 158 56 186 245


Duchesne Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		70%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		30%
Exceedance
Volume		10%
Exceedance
Volume
Big Brush Ck
Vernal, Nr, Red Fleet Res, Abv April-July8 11.4 12.9 61 15.7 22
Ashley Ck
Vernal, Nr April-July16.7 21 29 58 33 55
West Fork Duchesne
Vat Diversion, Blo April-July5 7.1 8.5 46 10.2 17.1
Duchesne
Tabiona, Nr April-July51 60 72 67 79 104
Rock Ck
Upper Stillwater Res April-July36 42 50 68 61 83
South Fork Rock Ck
Docs Div, Blo April-July2.1 3.1 3.7 51 5 6
Rock Ck
Mountain Home, Nr April-July42 49 59 67 72 98
Currant Ck
Currant Ck Res April-July4.1 5.8 7.5 38 10.9 18.7
Strawberry
Solider Springs,nr April-July11.3 17.7 23 32 31 47
Starvation Res, Duchesne, Nr April-July25 37 45 40 57 84
Duchesne
Duchesne, Nr, Knight Div, Abv April-July90 109 129 66 147 205
Lake Fork
Moon Lake Res, Mtn Home, Nr April-July29 35 42 64 51 72
Yellowstone
Altonah, Nr April-July28 35 41 67 48 65
Whiterocks
Whiterocks, Nr April-July19.8 27 33 61 38 58
Uinta
Neola, Nr April-July27 41 50 68 58 80
Duchesne
Myton April-July80 113 150 45 197 315
Randlett, Nr April-July88 119 154 40 205 340


Lower Green Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		70%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		30%
Exceedance
Volume		10%
Exceedance
Volume
White
Blo Tabbyune Ck, Soldier Summit, Nr April-July1.7 3.6 4.9 32 6.7 9.9
Fish Ck
Scofield, Nr, Reservoir, Abv April-July6.3 8.6 10.7 36 15.5 24
Price
Scofield Res, Scofield, Nr April-July8.5 11.6 14 34 21 32
Green
Green River, Ut April-July1300 1620 1920 65 2290 3270
Huntington Ck
Electric Lake April-July3 3.7 4.3 32 5.3 8.7
Power Plant, Blo April-July15.1 16.4 17.4 44 19 25
Seeley Ck
Joes Vly Res, Orangeville, Nr April-July15.4 21 24 43 30 46
Ferron Ck
Ferron, Nr April-July8.5 13.3 16.2 43 21 32
Muddy Ck
Emery, Nr April-July4.1 6.3 6.7 34 8.2 12.9

Differences between the full period forecasts and the residual forecasts may not exactly equal the actual observed volumes due to rounding conventions (see Definitions section).

Green End of Month Reservoir Contents (kaf)

EOM
Contents		Percent
EOM
Average		Percent
Usable
Capacity		Last Year
EOM		Last Year
%Average		EOM
Average		Usable
Capacity
untitled Green
Fontenelle Res, Fontenelle Nr 165.2 110 48 184.2 123 150.1 344.8
untitled Big Sandy
Big Sandy Res, Farson, Nr 30.8 186 80 23.5 142 16.6 38.3
Blacks Fork
Meeks Cabin 10.0 87 34 11.2 97 11.5 29.9
untitled Ef Smiths Fork
Stateline Res, Robertson,nr 6.0 108 43 6.4 114 5.6 13.9
untitled Green
Flaming Gorge Res, Flaming Gorge Dam, At 3259.2 107 87 3087.3 101 3050.5 3749.0
untitled Strawberry
Solider Springs,nr 930.6 141 84 776.1 118 659.9 1105.9
Starvation Res, Duchesne, Nr 158.6 114 96 142.2 102 138.8 165.3
untitled Rock Ck
Upper Stillwater Res 9.4 109 30 15.1 175 8.6 31.4
untitled Lake Fork
Moon Lake Res, Mtn Home, Nr 25.2 103 69 24.7 101 24.4 36.5
untitled Big Brush Ck
Red Fleet Res, Vernal, Nr 19.8 109 77 21.4 118 18.0 25.7
untitled Price
Scofield Res, Scofield, Nr 50.0 167 76 14.5 49 29.9 65.8
untitled Seeley Ck
Joes Vly Res, Orangeville, Nr 45.3 115 72 30.4 77 39.3 62.5
untitled Huntington Ck
Electric Lake 24.5 128 78 16.1 84 19.2 31.5
untitled
TOTAL 4734.6 113 83 4353.2 104 4172.4 5700.4

Precipitation Maps




Definitions

10% exceedance forecast: Given the current hydrometeorological conditions, i.e current snowpack, soil moisture and streamflow, the volume that has a 10% chance of being exceeded. Previously referred to as "Reasonable Maximum Forecast".

50% exceedance forecast: Given the current hydrometeorological conditions, i.e current snowpack, soil moisture and streamflow, the volume that has a 50% chance of being exceeded. Previously referred to as "Most Probable Forecast".

90% exceedance forecast: Given the current hydrometeorological conditions, i.e current snowpack, soil moisture and streamflow, the volume that has a 90% chance of being exceeded. Previously referred to as "Reasonable Minimum Forecast".

Acre-Foot (af): The volume equal to one acre covered one foot deep (43,560 cubic feet). See kaf below.

Average: The arithmetic mean. The sum of the values divided by the number of values. Values from 1981-2010 are used for this publication.

Categories: Much Above Average=Greater than 130%, Above Average=111-130%, Near Average=90-110%, Below Average=70-89%, Much Below Average=Less than 70%.

CBRFC: Colorado Basin River Forecast Center.

Forecast Period: The period from April 1 through July 31, unless otherwise noted.

kaf: Thousand Acre-Feet. See Acre-Foot above.

Inflow: The volume of water that flows into a reservoir or lake.

Median: The middle value of an ordered set of values. Half of the values are higher and half of the values are lower. When the set contains an even number of values the median is the average of the two middle numbers.

NOAA: National Oceanic and Atomospheric Administration.

NWS: National Weather Service.

Rounding Conventions:
RangeRound to
0-1.990.01
2.0-19.90.1
20-1991.0
200-9995.0
1000+3 significant digits


Streamflow: The volume of water that flows past a specific stream site.

Water Year: The 12-month period, October 1 through September 30. The water year is designated by the calendar year in which it ends. Thus, the year ending September 30, 2008, is called the "2008 water year."


Additional Information

Water supply forecasts take into consideration present hydrometeorological conditions and use average basin temperatures and precipitation for the forecast period. As the forecast season progresses, a greater portion of the future hydrologic and climatic uncertainty becomes known and monthly forecasts become more accurate. For more information on the tools we use, consult Water Supply Forecasting Tools.

Volume forecasts represent adjusted flows; that is, observed flows with upstream water use taken into account. Adjusted flows will closely approximate natural or unimpaired flows. However, not all upstream diversions or impoundments are measured or quantifiable. For specific adjustments used with each forecast point, consult the Guide to Water Supply Forecasting.

The Water Supply Outlook is issued monthly January through May by the Colorado Basin River Forecast Center. It represents a coordinated effort between the National Weather Service, Natural Resources Conservation Service, Bureau of Reclamation, U.S. Geological Survey and local water district managers.

Note: Data used in this report are provisional and are subject to revision.

For more information, or to be included on the mailing list, please contact:

Colorado Basin River Forecast Center
2242 W North Temple
Salt Lake City, UT 84116
(801) 524-5130
www.cbrfc.noaa.gov


Hydrologist: Ashley Nielson