Green Water Supply Outlook, June 1, 2020

Note: This publication is scheduled for revision. If you have feedback on content, format, or publication frequency, please contact us.
Prepared by Brenda Alcorn
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-July200 215 225 92 245 265
June-July133 148 158 94 178 200
Pine Ck
Fremont Lk, Abv April-July60 64 72 73 78 90
June-July43 47 55 72 61 73
New Fork
Big Piney, Nr April-July171 186 210 59 235 270
June-July90 105 129 51 156 190
Green
Fontenelle Reservoir, Fontenelle, Nr April-July500 535 590 81 645 735
June-July255 290 345 73 400 490
Big Sandy
Farson, Nr April-July20 22 25 48 28 35
June-July9.7 11.5 14.7 43 17.9 25
Green
Green River, Wy, Nr April-July505 545 600 82 655 745
June-July250 290 345 72 400 490
Hams Fork
Frontier, Nr, Pole Ck, Blo April-July30 32 36 67 40 45
June-July7 9.2 13.4 52 17 22
Viva Naughton Reservoir April-July39 42 47 64 51 57
June-July7 9.6 14.5 47 19 25
Blacks Fork
Robertson, Nr April-July67 75 83 93 90 97
June-July25 33 41 69 48 55
Ef Smiths Fork
Stateline Reservoir, Robertson,nr April-July24 26 28 108 31 32
June-July9 10.7 12.8 72 15.3 17
Green
Flaming Gorge Reservoir April-July650 685 740 76 830 910
June-July320 355 410 68 500 580


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-July19.8 21 23 100 25 27
June-July3 4.5 6.2 72 8 10
Steamboat Springs April-July240 250 260 100 280 300
June-July70 80 90 76 110 130
Elk
Milner, Nr April-July270 285 300 94 320 355
June-July100 114 129 81 150 185
Elkhead Ck
Long Gulch, Abv, Hayden, Nr April-July67 69 70 96 73 78
June-July2 3.4 4.8 46 7.5 13
Yampa
Maybell, Nr April-July780 815 860 92 935 980
June-July220 255 300 77 375 420
Little Snake
Slater, Nr April-July128 138 147 94 158 168
June-July25 35 44 67 55 65
Dixon, Nr April-July245 260 275 80 300 325
June-July45 60 76 56 99 125
Lily, Nr April-July235 255 270 78 290 320
June-July40 60 75 56 97 125
Yampa
Deerlodge Park April-July980 1040 1130 91 1210 1310
June-July220 280 370 74 450 550
White
Meeker, Nr April-July162 173 185 66 200 220
June-July60 71 83 58 100 120
Watson, Nr April-July145 158 175 63 190 210
June-July60 73 90 65 105 125


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-July11 11.9 13 62 14.4 15.7
June-July2.1 3 4.1 46 5.5 6.8
Ashley Ck
Vernal, Nr April-July25 28 30 60 33 35
June-July6.5 9 11.5 48 14 16.5
West Fork Duchesne
Vat Diversion, Blo April-July12 13 14 75 15 16.5
June-July2.5 3.5 4.5 48 5.5 7
Duchesne
Tabiona, Nr April-July74 82 87 81 92 100
June-July25 33 38 63 43 51
Rock Ck
Upper Stillwater Reservoir April-July61 66 70 95 76 81
June-July25 30 34 72 40 45
South Fork Rock Ck
Docs Div, Blo April-July4.8 5.1 5.5 75 5.9 6.3
June-July2 2.3 2.7 55 3.1 3.5
Rock Ck
Mountain Home, Nr April-July72 77 80 91 84 92
June-July33 38 41 73 45 53
Currant Ck
Currant Ck Reservoir April-July12.5 13.3 14 70 14.8 15.5
June-July1.7 2.5 3.2 43 4 4.7
Strawberry
Strawberry Reservoir, Soldier Springs April-July18 19.9 21 30 24 26
June-July4.1 6 7.1 30 10 12
Starvation Reservoir, Duchesne, Nr April-July40 46 50 45 53 56
June-July8.9 15 18.9 50 22 25
Duchesne
Duchesne, Nr, Knight Div, Abv April-July150 158 165 85 177 190
June-July60 68 75 65 87 100
Lake Fork
Moon Lake Reservoir, Mtn Home, Nr April-July54 56 60 91 64 69
June-July25 27 31 72 35 40
Yellowstone
Altonah, Nr April-July52 56 60 98 62 68
June-July27 31 35 85 37 43
Whiterocks
Whiterocks, Nr April-July32 36 40 74 42 46
June-July13 17.6 21 62 23 27
Uinta
Neola, Nr April-July56 61 65 88 69 76
June-July27 32 36 72 40 47
Duchesne
Myton April-July188 196 210 64 230 260
June-July60 68 82 47 100 132
Randlett, Nr April-July193 205 220 57 240 275
June-July60 70 87 41 106 140


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-July4.3 4.4 4.5 29 5 5.5
June-July0.67 0.77 0.9 26 1.4 1.9
Fish Ck
Scofield, Nr, Reservoir, Abv April-July14.3 14.8 15.1 50 15.9 16.8
June-July2.5 3 3.3 34 4.1 5
Price
Scofield Reservoir, Scofield, Nr April-July17.8 18.4 19.1 47 20 21
June-July2.7 3.3 4 30 5.2 6.2
Green
Green River, Ut April-July1940 2070 2220 75 2390 2640
June-July750 880 1030 66 1200 1450
Huntington Ck
Electric Lake April-July7.1 7.4 7.9 59 8.6 9.5
June-July1.2 1.5 2 42 2.7 3.6
Power Plant, Blo April-July24 25 26 65 28 29
June-July10.3 11.2 12 61 13.9 15.1
Seeley Ck
Joes Vly Reservoir, Orangeville, Nr April-July37 40 42 75 46 49
June-July14.7 17.1 20 63 24 27
Ferron Ck
Ferron, Nr April-July26 28 29 76 31 33
June-July9.7 11.3 12.7 60 14.5 16.3
Muddy Ck
Emery, Nr April-July10.5 11.3 12 60 13 14.2
June-July4.6 5.4 6.1 52 7.1 8.3

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 Reservoir, Fontenelle, Nr 135.8 112 39 95.1 78 121.7 344.8
untitled Big Sandy
Big Sandy Reservoir, Nr Farson 24.5 125 64 17.6 90 19.6 38.3
Blacks Fork
Meeks Cabin 12.1 90 40 6.8 51 13.4 29.9
untitled Ef Smiths Fork
Stateline Reservoir, Robertson,nr 5.8 106 42 4.2 76 5.5 13.9
untitled Green
Flaming Gorge Reservoir 3220.1 107 86 3185.0 105 3021.3 3749.0
untitled Strawberry
Strawberry Reservoir, Soldier Springs 978.8 147 89 860.5 130 663.7 1105.9
Starvation Reservoir, Duchesne, Nr 164.7 110 100 142.6 95 149.7 165.3
untitled Rock Ck
Upper Stillwater Reservoir 6.6 149 21 2.1 48 4.5 31.4
untitled Lake Fork
Moon Lake Reservoir, Mtn Home, Nr 29.7 109 81 15.5 57 27.3 36.5
untitled Big Brush Ck
Red Fleet Reservoir, Vernal, Nr 22.0 115 85 13.3 70 19.0 25.7
untitled Price
Scofield Reservoir, Scofield, Nr 52.2 169 79 28.6 93 30.9 65.8
untitled Seeley Ck
Joes Vly Reservoir, Orangeville, Nr 48.5 121 78 30.0 75 40.0 62.5
untitled Huntington Ck
Electric Lake 22.7 124 72 16.2 89 18.3 31.5
untitled
TOTAL 4723.6 114 83 4417.5 107 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: Brenda Alcorn