Green Water Supply Outlook, January 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-July190 235 280 114 315 375
Pine Ck
Fremont Lk, Abv April-July74 86 100 102 109 127
New Fork
Big Piney, Nr April-July240 310 355 100 420 515
Green
Fontenelle Res, Fontenelle Nr April-July455 645 780 108 925 1150
Big Sandy
Farson, Nr April-July30 43 50 96 57 75
Green
Green River, Wy, Nr April-July470 665 785 108 930 1170
Hams Fork
Frontier, Nr, Pole Ck, Blo April-July23 29 40 74 49 67
Viva Naughton Res April-July27 38 53 72 69 103
Blacks Fork
Robertson, Nr April-July47 66 77 87 91 112
Ef Smiths Fork
Stateline Res, Robertson,nr April-July14.9 19.8 23 88 28 33
Green
Flaming Gorge Res, Flaming Gorge Dam, At April-July580 800 1000 102 1160 1550


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-July12.5 15.1 16.5 72 17 19.9
Steamboat Springs April-July98 140 188 72 220 270
Elk
Milner, Nr April-July145 195 260 81 305 340
Elkhead Ck
Long Gulch, Abv, Hayden, Nr April-July17.9 30 46 63 57 66
Yampa
Maybell, Nr April-July310 450 665 71 770 950
Little Snake
Slater, Nr April-July53 73 107 69 131 161
Dixon, Nr April-July100 143 205 59 245 350
Lily, Nr April-July91 140 210 61 260 390
Yampa
Deerlodge Park April-July390 595 870 70 1030 1260
White
Meeker, Nr April-July112 137 182 65 200 245
Watson, Nr April-July112 139 185 66 215 255


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 11.8 13.2 63 16.1 22
Ashley Ck
Vernal, Nr April-July17 26 30 60 36 55
West Fork Duchesne
Vat Diversion, Blo April-July4.9 8.3 10.5 56 13.2 18.9
Duchesne
Tabiona, Nr April-July49 65 80 74 98 115
Rock Ck
Upper Stillwater Res April-July35 45 55 74 65 83
South Fork Rock Ck
Docs Div, Blo April-July2.4 3.2 4.1 56 5.6 7.9
Rock Ck
Mountain Home, Nr April-July42 54 65 74 77 100
Currant Ck
Currant Ck Res April-July4.2 6.6 10.6 53 14.8 21
Strawberry
Solider Springs,nr April-July12.3 22 27 38 39 59
Starvation Res, Duchesne, Nr April-July30 46 55 49 81 107
Duchesne
Duchesne, Nr, Knight Div, Abv April-July91 119 143 74 170 215
Lake Fork
Moon Lake Res, Mtn Home, Nr April-July27 36 44 67 55 72
Yellowstone
Altonah, Nr April-July28 36 45 74 52 66
Whiterocks
Whiterocks, Nr April-July19.7 28 33 61 42 58
Uinta
Neola, Nr April-July27 38 53 72 63 80
Duchesne
Myton April-July81 128 185 56 250 355
Randlett, Nr April-July91 137 195 51 265 385


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-July1.8 4.5 6.8 44 8.7 11.8
Fish Ck
Scofield, Nr, Reservoir, Abv April-July4.7 9.3 13.2 44 19.9 25
Price
Scofield Res, Scofield, Nr April-July6.5 12.1 17.5 43 26 33
Green
Green River, Ut April-July1300 1640 2190 74 2470 3400
Huntington Ck
Electric Lake April-July3.1 4.2 5.3 40 6.8 9.8
Power Plant, Blo April-July15.4 17.6 19 48 22 26
Seeley Ck
Joes Vly Res, Orangeville, Nr April-July14.8 21 29 52 33 47
Ferron Ck
Ferron, Nr April-July9.9 13.5 19 50 25 34
Muddy Ck
Emery, Nr April-July4.7 7.3 8 40 10.5 15.3

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 203.6 116 59 203.2 116 175.3 344.8
untitled Big Sandy
Big Sandy Res, Farson, Nr 29.9 193 78 22.0 142 15.5 38.3
Blacks Fork
Meeks Cabin 8.7 84 29 9.7 94 10.3 29.9
untitled Ef Smiths Fork
Stateline Res, Robertson,nr 5.8 101 42 6.0 104 5.8 13.9
untitled Green
Flaming Gorge Res, Flaming Gorge Dam, At 3343.2 108 89 3130.4 101 3094.9 3749.0
untitled Strawberry
Solider Springs,nr 929.4 141 84 766.8 116 659.7 1105.9
Starvation Res, Duchesne, Nr 150.0 112 91 142.1 106 134.1 165.3
untitled Rock Ck
Upper Stillwater Res 9.3 90 30 14.5 139 10.4 31.4
untitled Lake Fork
Moon Lake Res, Mtn Home, Nr 23.7 106 65 22.3 100 22.4 36.5
untitled Big Brush Ck
Red Fleet Res, Vernal, Nr 19.1 109 74 20.8 119 17.5 25.7
untitled Price
Scofield Res, Scofield, Nr 48.4 170 74 12.3 43 28.5 65.8
untitled Seeley Ck
Joes Vly Res, Orangeville, Nr 45.5 115 73 29.8 75 39.7 62.5
untitled Huntington Ck
Electric Lake 25.1 128 80 15.9 81 19.6 31.5
untitled
TOTAL 4841.8 114 85 4395.9 104 4233.8 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