Green Water Supply Outlook, March 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-July250 290 310 127 335 380
Pine Ck
Fremont Lk, Abv April-July78 87 100 102 104 118
New Fork
Big Piney, Nr April-July260 300 355 100 405 475
Green
Fontenelle Res, Fontenelle Nr April-July620 730 840 116 955 1120
Big Sandy
Farson, Nr April-July36 44 50 96 56 70
Green
Green River, Wy, Nr April-July655 790 845 116 985 1150
Hams Fork
Frontier, Nr, Pole Ck, Blo April-July25 30 36 67 45 58
Viva Naughton Res April-July31 38 45 61 56 79
Blacks Fork
Robertson, Nr April-July46 56 65 73 79 100
Ef Smiths Fork
Stateline Res, Robertson,nr April-July15.1 18.8 21 81 24 29
Green
Flaming Gorge Res, Flaming Gorge Dam, At April-July700 850 940 96 1090 1420


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 12.8 14.5 63 15.2 18.2
Steamboat Springs April-July110 148 174 67 199 250
Elk
Milner, Nr April-July165 215 245 77 275 330
Elkhead Ck
Long Gulch, Abv, Hayden, Nr April-July23 31 41 56 47 60
Yampa
Maybell, Nr April-July365 480 595 64 680 850
Little Snake
Slater, Nr April-July63 82 100 64 117 152
Dixon, Nr April-July118 163 190 55 230 315
Lily, Nr April-July115 162 195 57 240 320
Yampa
Deerlodge Park April-July465 645 790 64 905 1150
White
Meeker, Nr April-July115 138 155 55 177 230
Watson, Nr April-July117 141 158 56 184 245


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-July7.5 10.5 12.9 61 14.4 20
Ashley Ck
Vernal, Nr April-July16.7 21 27 54 31 46
West Fork Duchesne
Vat Diversion, Blo April-July4.1 6.2 7.5 40 10 12.6
Duchesne
Tabiona, Nr April-July45 53 60 56 70 82
Rock Ck
Upper Stillwater Res April-July32 39 47 64 56 64
South Fork Rock Ck
Docs Div, Blo April-July1.7 2.4 3.2 44 3.8 4.8
Rock Ck
Mountain Home, Nr April-July37 46 56 64 67 77
Currant Ck
Currant Ck Res April-July4.2 4.6 6 30 8.5 12
Strawberry
Solider Springs,nr April-July11 15.8 20 28 25 37
Starvation Res, Duchesne, Nr April-July25 32 38 34 48 65
Duchesne
Duchesne, Nr, Knight Div, Abv April-July80 98 114 59 133 149
Lake Fork
Moon Lake Res, Mtn Home, Nr April-July21 29 38 58 42 54
Yellowstone
Altonah, Nr April-July25 34 39 64 46 55
Whiterocks
Whiterocks, Nr April-July18.4 23 30 56 35 46
Uinta
Neola, Nr April-July26 37 48 65 55 69
Duchesne
Myton April-July67 99 130 39 163 215
Randlett, Nr April-July74 104 133 35 164 230


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 3.1 3.9 25 6 8.5
Fish Ck
Scofield, Nr, Reservoir, Abv April-July6.6 8 10.7 36 12.8 19.5
Price
Scofield Res, Scofield, Nr April-July8.9 10.8 14 34 16.8 26
Green
Green River, Ut April-July1450 1710 1920 65 2300 2860
Huntington Ck
Electric Lake April-July3.2 3.7 4.3 32 4.9 7.8
Power Plant, Blo April-July15.4 16.3 17.4 44 18.3 25
Seeley Ck
Joes Vly Res, Orangeville, Nr April-July16.9 22 24 43 29 40
Ferron Ck
Ferron, Nr April-July10.8 16 20 53 24 35
Muddy Ck
Emery, Nr April-July4.6 6.2 7.5 38 8.1 11.1

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 130.9 103 38 177.6 139 127.6 344.8
untitled Big Sandy
Big Sandy Res, Farson, Nr 31.6 210 83 24.7 164 15.1 38.3
Blacks Fork
Meeks Cabin 11.1 90 37 12.5 101 12.3 29.9
untitled Ef Smiths Fork
Stateline Res, Robertson,nr 6.1 114 44 6.6 123 5.4 13.9
untitled Green
Flaming Gorge Res, Flaming Gorge Dam, At 3194.0 106 85 3088.1 102 3015.6 3749.0
untitled Strawberry
Solider Springs,nr 932.0 141 84 784.2 119 660.2 1105.9
Starvation Res, Duchesne, Nr 165.3 114 100 129.4 90 144.5 165.3
untitled Rock Ck
Upper Stillwater Res 9.2 120 29 12.7 166 7.6 31.4
untitled Lake Fork
Moon Lake Res, Mtn Home, Nr 25.6 96 70 26.6 100 26.6 36.5
untitled Big Brush Ck
Red Fleet Res, Vernal, Nr 20.3 110 79 21.3 115 18.5 25.7
untitled Price
Scofield Res, Scofield, Nr 51.4 168 78 16.6 54 30.6 65.8
untitled Seeley Ck
Joes Vly Res, Orangeville, Nr 45.6 113 73 31.0 77 40.2 62.5
untitled Huntington Ck
Electric Lake 23.9 127 76 16.1 86 18.8 31.5
untitled
TOTAL 4646.9 113 82 4347.3 105 4123.0 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