Green Water Supply Outlook, April 1, 2017

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-July380 400 430 176 460 480
Pine Ck
Fremont Lk, Abv April-July133 143 148 151 159 166
New Fork
Big Piney, Nr April-July560 600 660 186 720 770
Green
Fontenelle Res, Fontenelle Nr April-July1390 1500 1680 232 1780 1920
Big Sandy
Farson, Nr April-July72 81 86 165 95 104
Green
Green River, Wy, Nr April-July1410 1530 1730 237 1860 2000
Hams Fork
Frontier, Nr, Pole Ck, Blo April-July90 95 108 200 121 132
Viva Naughton Res April-July132 143 162 219 182 200
Blacks Fork
Robertson, Nr April-July103 113 122 137 136 151
Ef Smiths Fork
Stateline Res, Robertson,nr April-July30 33 37 142 40 44
Green
Flaming Gorge Res, Flaming Gorge Dam, At April-July1840 1930 2260 231 2500 2670


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-July13.5 15.1 16.5 72 17.5 21
Steamboat Springs April-July145 163 190 73 210 255
Elk
Milner, Nr April-July220 265 290 91 330 365
Elkhead Ck
Long Gulch, Abv, Hayden, Nr April-July42 54 59 81 69 80
Yampa
Maybell, Nr April-July575 685 750 80 880 985
Little Snake
Slater, Nr April-July103 131 145 93 160 190
Dixon, Nr April-July200 260 290 84 330 410
Lily, Nr April-July200 270 310 90 345 440
Yampa
Deerlodge Park April-July765 960 1050 85 1190 1370
White
Meeker, Nr April-July182 210 230 82 245 285
Watson, Nr April-July190 220 245 88 260 305


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-July20 23 27 129 29 37
Ashley Ck
Vernal, Nr April-July52 62 68 136 71 95
West Fork Duchesne
Vat Diversion, Blo April-July32 34 36 194 38 42
Duchesne
Tabiona, Nr April-July162 175 183 169 194 210
Rock Ck
Upper Stillwater Res April-July106 116 126 170 132 148
South Fork Rock Ck
Docs Div, Blo April-July11.5 12.9 13.8 189 14.7 16
Rock Ck
Mountain Home, Nr April-July130 144 155 176 162 180
Currant Ck
Currant Ck Res April-July35 39 42 210 45 50
Strawberry
Solider Springs,nr April-July95 104 115 162 129 139
Starvation Res, Duchesne, Nr April-July200 215 230 205 250 270
Duchesne
Duchesne, Nr, Knight Div, Abv April-July290 320 335 173 355 390
Lake Fork
Moon Lake Res, Mtn Home, Nr April-July91 102 108 164 116 129
Yellowstone
Altonah, Nr April-July83 97 103 169 108 126
Whiterocks
Whiterocks, Nr April-July71 77 85 157 90 110
Uinta
Neola, Nr April-July101 114 125 169 129 154
Duchesne
Myton April-July530 605 650 197 700 800
Randlett, Nr April-July630 720 795 206 845 985


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-July25 28 30 194 32 37
Fish Ck
Scofield, Nr, Reservoir, Abv April-July46 49 52 173 56 62
Price
Scofield Res, Scofield, Nr April-July64 70 73 178 78 88
Green
Green River, Ut April-July3800 4270 4500 152 4950 5600
Huntington Ck
Electric Lake April-July22 26 28 211 29 33
Power Plant, Blo April-July68 79 82 205 87 99
Seeley Ck
Joes Vly Res, Orangeville, Nr April-July62 71 75 134 80 94
Ferron Ck
Ferron, Nr April-July45 51 56 147 59 68
Muddy Ck
Emery, Nr April-July19.8 23 25 126 28 33

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 206.8 170 60 139.5 115 121.7 344.8
untitled Big Sandy
Big Sandy Res, Farson, Nr 30.5 156 80 21.9 111 19.6 38.3
Blacks Fork
Meeks Cabin 15.8 118 53 9.5 71 13.4 29.9
untitled Ef Smiths Fork
Stateline Res, Robertson,nr 7.4 135 54 6.6 120 5.5 13.9
untitled Green
Flaming Gorge Res, Flaming Gorge Dam, At 3169.4 105 85 3165.0 105 3021.3 3749.0
untitled Strawberry
Solider Springs,nr 807.0 122 73 801.0 121 663.7 1105.9
Starvation Res, Duchesne, Nr 117.9 79 71 159.4 106 149.7 165.3
untitled Rock Ck
Upper Stillwater Res 2.3 51 7 2.1 48 4.5 31.4
untitled Lake Fork
Moon Lake Res, Mtn Home, Nr 30.1 111 83 24.6 90 27.3 36.5
untitled Big Brush Ck
Red Fleet Res, Vernal, Nr 20.2 106 79 17.4 92 19.0 25.7
untitled Price
Scofield Res, Scofield, Nr 21.7 70 33 13.8 45 30.9 65.8
untitled Seeley Ck
Joes Vly Res, Orangeville, Nr 32.7 82 52 37.2 93 40.0 62.5
untitled Huntington Ck
Electric Lake 16.5 90 52 16.6 91 18.3 31.5
untitled
TOTAL 4478.4 108 79 4414.6 107 4134.9 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