New 1991-2020 Averages being used this year.
Green Water Supply Outlook, May 1, 2022

Green Water Supply Outlook, May 1, 2022

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-July160 180 200 78 220 240
May-July150 170 190 81 210 230
Pine Ck
Fremont Lk, Abv April-July50 57 70 69 78 87
May-July48 55 68 69 76 85
New Fork
Big Piney, Nr April-July125 155 200 56 235 295
May-July110 140 185 56 220 280
Green
Fontenelle Reservoir, Fontenelle, Nr April-July320 385 475 65 540 620
May-July270 335 425 65 490 570
Big Sandy
Farson, Nr April-July22 25 33 66 42 48
May-July20 23 31 67 40 46
Green
Green River, Wy, Nr April-July310 380 465 63 540 620
May-July260 330 415 64 490 570
Hams Fork
Frontier, Nr, Pole Ck, Blo April-July17.6 19.6 25 48 31 37
May-July14 16 21 46 27 33
Viva Naughton Reservoir April-July24 26 32 44 40 48
May-July16 18 24 40 32 40
Blacks Fork
Robertson, Nr April-July50 53 63 72 73 86
May-July47 50 60 72 70 83
Ef Smiths Fork
Stateline Reservoir, Robertson,nr April-July16.4 17.4 20 71 23 27
May-July15 16 18.6 72 22 26
Green
Flaming Gorge Reservoir April-July395 455 550 57 665 765
May-July330 390 485 58 600 700


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 20 21 78 22 24
May-July15 16 17 81 17.5 20
Steamboat Springs April-July162 182 200 77 220 245
May-July140 160 178 81 200 225
Elk
Milner, Nr April-July265 290 305 92 330 360
May-July235 260 275 92 300 330
Elkhead Ck
Long Gulch, Abv, Hayden, Nr April-July46 49 55 77 61 71
May-July35 38 44 90 50 60
Yampa
Maybell, Nr April-July595 655 730 79 795 895
May-July500 560 635 84 700 800
Little Snake
Slater, Nr April-July98 109 125 81 138 153
May-July85 96 112 82 125 140
Dixon, Nr April-July174 199 230 70 250 285
May-July140 165 195 70 215 250
Lily, Nr April-July180 205 235 72 260 295
May-July145 170 200 74 225 260
Yampa
Deerlodge Park April-July775 855 955 80 1040 1170
May-July650 730 830 85 915 1050
White
Meeker, Nr April-July155 168 185 71 205 245
May-July130 143 160 71 180 220
Watson, Nr April-July151 163 181 67 200 240
May-July125 137 155 66 175 215


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-July9.5 10.7 12 61 14.2 16.7
May-July7.8 9 10.3 61 12.5 15
Ashley Ck
Vernal, Nr April-July19.8 22 25 54 30 39
May-July17 19 22 50 27 36
West Fork Duchesne
Vat Diversion, Blo April-July9.1 10.6 12 71 13.1 14.6
May-July8 9.5 10.9 69 12 13.5
Duchesne
Tabiona, Nr April-July64 68 75 73 89 94
May-July55 59 66 71 80 85
Rock Ck
Upper Stillwater Reservoir April-July46 51 60 83 71 76
May-July40 45 54 78 65 70
South Fork Rock Ck
Docs Div, Blo April-July4.1 4.6 5.2 71 6.1 7.1
May-July3.5 4 4.6 68 5.5 6.5
Rock Ck
Mountain Home, Nr April-July57 62 72 83 80 87
May-July50 55 65 79 73 80
Currant Ck
Currant Ck Reservoir April-July8.6 10 12 68 13.6 15.6
May-July7 8.4 10.4 68 12 14
Strawberry
Strawberry Reservoir, Soldier Springs April-July23 27 30 50 38 43
May-July10 14 17.5 36 25 30
Starvation Reservoir, Duchesne, Nr April-July30 37 45 48 60 68
May-July15 22 30 40 45 53
Duchesne
Duchesne, Nr, Knight Div, Abv April-July120 130 145 77 165 175
May-July105 115 130 75 150 160
Lake Fork
Moon Lake Reservoir, Mtn Home, Nr April-July34 38 45 70 52 64
May-July30 34 41 68 48 60
Yellowstone
Altonah, Nr April-July34 39 45 75 53 59
May-July30 35 41 73 49 55
Whiterocks
Whiterocks, Nr April-July25 28 35 69 43 53
May-July22 25 32 67 40 50
Uinta
Neola, Nr April-July35 41 50 69 58 73
May-July32 38 47 68 55 70
Duchesne
Myton April-July130 145 175 57 215 255
May-July100 115 145 54 185 225
Randlett, Nr April-July140 155 185 53 225 270
May-July110 125 155 50 195 240


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-July5 5.5 6.5 52 8 9.5
May-July3 3.5 4.5 47 6 7.5
Fish Ck
Scofield, Nr, Reservoir, Abv April-July14.7 17.2 19 73 23 25
May-July12 14.5 16.3 74 20 22
Price
Scofield Reservoir, Scofield, Nr April-July18.8 21 24 71 30 32
May-July14 16.5 19.2 66 25 27
Green
Green River, Ut April-July1440 1640 1800 64 2110 2340
May-July1200 1400 1560 64 1870 2100
Huntington Ck
Electric Lake April-July5.7 6.5 7.5 66 9.2 10.7
May-July5 5.8 6.8 68 8.5 10
Power Plant, Blo April-July22 27 30 75 36 39
May-July20 25 28 76 34 37
Seeley Ck
Joes Vly Reservoir, Orangeville, Nr April-July28 31 36 71 40 43
May-July25 28 33 70 37 40
Ferron Ck
Ferron, Nr April-July16.9 18.9 22 63 25 28
May-July15 17 20 61 23 26
Muddy Ck
Emery, Nr April-July6.8 8.3 9 49 10.8 11.8
May-July6 7.5 8.2 49 10 11

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 152.0 112 46 125.2 92 136.2 334.0
untitled Big Sandy
Big Sandy Reservoir, Nr Farson 10.5 47 27 11.5 51 22.4 38.3
Blacks Fork
Meeks Cabin 16.6 96 56 8.4 49 17.3 29.9
untitled Ef Smiths Fork
Stateline Reservoir, Robertson,nr 7.2 110 52 4.5 69 6.5 13.9
untitled Green
Flaming Gorge Reservoir 2937.8 95 78 3178.3 103 3087.2 3749.0
untitled Strawberry
Strawberry Reservoir, Soldier Springs 855.2 103 77 926.2 112 828.0 1105.9
Starvation Reservoir, Duchesne, Nr 156.1 102 94 164.9 107 153.6 165.3
untitled Rock Ck
Upper Stillwater Reservoir 2.5 85 8 4.0 134 3.0 31.4
untitled Lake Fork
Moon Lake Reservoir, Mtn Home, Nr 27.2 119 74 16.0 70 22.9 36.5
untitled Big Brush Ck
Red Fleet Reservoir, Vernal, Nr 12.5 64 49 16.7 86 19.4 25.7
untitled Price
Scofield Reservoir, Scofield, Nr 25.4 85 39 36.8 123 29.9 65.8
untitled Seeley Ck
Joes Vly Reservoir, Orangeville, Nr 23.2 60 37 37.4 97 38.5 62.5
untitled Huntington Ck
Electric Lake 10.8 61 34 18.4 105 17.6 31.5
untitled
TOTAL 4237.0 97 74 4548.3 104 4382.6 5689.6

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 1991-2020 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