nLake Powell Water Supply Outlook, June 1, 2017

Lake Powell Water Supply Outlook, June 1, 2017

Note: This publication is scheduled for revision. If you have feedback on content, format, or publication frequency, please contact us.
Prepared by CBRFC
NOAA, National Weather Service
Colorado Basin River Forecast Center
Salt Lake City, Utah
www.cbrfc.noaa.gov

Contents

Lake Powell Sub-Basin Summaries




*Median of forecasts within each basin.





*Median of forecasts within each basin.







*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 Colorado Mainstem Basin Conditions




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Gunnison Basin Conditions




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Dolores Basin Conditions




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

San Juan 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-July395 410 430 176 445 465
June-July250 265 285 170 300 320
Pine Ck
Fremont Lk, Abv April-July136 143 148 151 152 161
June-July111 118 123 162 127 136
New Fork
Big Piney, Nr April-July600 620 670 189 710 730
June-July410 430 480 188 520 540
Green
Fontenelle Res, Fontenelle Nr April-July1540 1620 1680 232 1730 1820
June-July890 965 1030 217 1080 1170
Big Sandy
Farson, Nr April-July72 76 81 156 84 88
June-July46 50 55 162 58 62
Green
Green River, Wy, Nr April-July1580 1650 1710 234 1780 1860
June-July920 995 1050 219 1120 1200
Hams Fork
Frontier, Nr, Pole Ck, Blo April-July105 109 113 209 117 124
June-July34 38 42 162 46 53
Viva Naughton Res April-July150 155 161 218 165 173
June-July41 46 52 168 56 64
Blacks Fork
Robertson, Nr April-July102 107 114 128 119 125
June-July53 58 65 110 70 76
Ef Smiths Fork
Stateline Res, Robertson,nr April-July33 35 37 142 39 41
June-July17 18.5 21 118 23 25
Green
Flaming Gorge Res, Flaming Gorge Dam, At April-July1950 2060 2180 222 2260 2380
June-July1020 1130 1250 208 1330 1450


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-July12.6 13.2 13.9 60 14.5 15.5
June-July6.1 6.7 7.4 86 8 9
Steamboat Springs April-July183 192 200 77 210 230
June-July82 91 99 83 109 130
Elk
Milner, Nr April-July305 320 340 106 355 385
June-July100 116 136 86 150 180
Elkhead Ck
Long Gulch, Abv, Hayden, Nr April-July64 65 67 92 68 71
June-July5 5.4 7.5 72 8.9 12
Yampa
Maybell, Nr April-July695 730 770 82 800 865
June-July240 275 315 81 345 410
Little Snake
Slater, Nr April-July118 125 132 85 139 148
June-July33 40 47 71 54 63
Dixon, Nr April-July235 240 255 74 270 290
June-July71 79 92 68 108 127
Lily, Nr April-July245 255 270 78 285 305
June-July70 78 91 68 108 128
Yampa
Deerlodge Park April-July930 980 1030 83 1070 1170
June-July320 370 415 83 455 560
White
Meeker, Nr April-July192 198 205 73 215 230
June-July85 91 99 69 108 125
Watson, Nr April-July196 205 215 77 225 245
June-July87 97 106 76 115 135


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 21 21 100 22 24
June-July5 5.7 6.1 68 6.8 9
Ashley Ck
Vernal, Nr April-July49 53 55 110 56 60
June-July17 21 23 96 24 28
West Fork Duchesne
Vat Diversion, Blo April-July32 33 34 183 36 37
June-July15 15.9 17 183 18.4 20
Duchesne
Tabiona, Nr April-July162 167 174 161 179 190
June-July87 92 99 165 104 115
Rock Ck
Upper Stillwater Res April-July102 107 111 150 114 122
June-July58 63 67 143 70 78
South Fork Rock Ck
Docs Div, Blo April-July10.4 11.2 11.5 158 11.9 12.8
June-July6.1 6.9 7.2 147 7.6 8.5
Rock Ck
Mountain Home, Nr April-July125 130 134 152 138 145
June-July70 75 79 141 83 90
Currant Ck
Currant Ck Res April-July31 32 33 165 34 37
June-July9.5 10.5 12 162 13.3 15.5
Strawberry
Solider Springs,nr April-July107 108 112 158 114 117
June-July22 23 27 113 29 32
Starvation Res, Duchesne, Nr April-July195 197 205 183 210 215
June-July50 52 61 161 64 70
Duchesne
Duchesne, Nr, Knight Div, Abv April-July285 295 300 155 310 325
June-July157 167 175 152 181 196
Lake Fork
Moon Lake Res, Mtn Home, Nr April-July88 91 95 144 100 104
June-July51 54 58 135 63 67
Yellowstone
Altonah, Nr April-July88 91 97 159 102 107
June-July53 56 62 151 67 72
Whiterocks
Whiterocks, Nr April-July61 65 70 130 74 79
June-July32 36 41 121 45 50
Uinta
Neola, Nr April-July101 105 112 151 118 124
June-July63 67 74 148 80 86
Duchesne
Myton April-July535 555 580 176 595 625
June-July240 260 285 165 300 330
Randlett, Nr April-July610 640 680 177 700 740
June-July280 310 350 167 370 410


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-July24 24 25 161 25 26
June-July3 3 3.5 103 3.7 4.5
Fish Ck
Scofield, Nr, Reservoir, Abv April-July35 36 37 123 38 41
June-July6 6.4 7.5 77 8.2 11.2
Price
Scofield Res, Scofield, Nr April-July52 54 57 139 60 63
June-July8 9.8 13 97 16 19
Green
Green River, Ut April-July3870 4020 4230 143 4370 4670
June-July1800 1950 2160 139 2300 2600
Huntington Ck
Electric Lake April-July21 21 22 165 23 25
June-July5 5.5 6.5 135 6.8 9.5
Power Plant, Blo April-July55 57 60 150 63 68
June-July23 25 28 141 31 36
Seeley Ck
Joes Vly Res, Orangeville, Nr April-July69 72 75 134 78 82
June-July30 33 36 113 39 43
Ferron Ck
Ferron, Nr April-July51 54 56 147 58 61
June-July23 26 28 133 30 33
Muddy Ck
Emery, Nr April-July23 24 25 126 26 28
June-July11 11.5 12.5 107 13.1 16


Upper Colorado Mainstem 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
Colorado
Lake Granby, Granby, Nr April-July215 230 240 109 255 275
June-July130 143 154 106 170 190
Willow Ck
Willow Ck Res, Granby, Nr April-July59 62 65 138 72 75
June-July14 17 20 95 27 30
Fraser
Winter Park April-July18 19.5 21 108 23 25
June-July13.5 15 16.5 116 18.5 20
Williams Fork
Williams Fork Res, Parshall, Nr April-July90 95 105 109 110 117
June-July63 68 78 120 83 90
Muddy Ck
Wolford Mountain Reservoir April-July36 38 42 78 46 49
June-July7 9.1 13.1 68 17.1 20
Blue
Dillon Res April-July160 175 185 113 195 205
June-July109 124 134 122 144 154
Green Mtn Res April-July260 285 305 111 320 340
June-July170 194 215 117 230 250
Colorado
Kremmling, Nr April-July850 900 950 110 1030 1070
June-July480 530 580 110 660 700
Eagle
Gypsum, Blo April-July255 265 290 87 315 330
June-July165 173 198 92 225 240
Colorado
Dotsero, Nr April-July1300 1350 1410 101 1500 1600
June-July750 800 860 102 950 1050
Frying Pan
Ruedi Res, Basalt, Nr April-July110 115 125 90 135 140
June-July66 71 81 91 91 96
Roaring Fork
Glenwood Springs April-July580 615 650 94 690 720
June-July390 425 460 101 500 530
Colorado
Glenwood Springs, Blo April-July1900 2000 2070 98 2250 2350
June-July1150 1250 1320 102 1500 1600
Cameo, Nr April-July2000 2140 2220 94 2390 2550
June-July1210 1350 1430 101 1600 1760
Plateau Ck
Cameo, Nr April-July60 65 75 60 80 90
June-July15 20 30 61 35 45
Colorado
Cisco, Nr April-July3900 4100 4310 97 4500 4700
June-July1990 2190 2400 103 2590 2790
Lake Powell, Glen Cyn Dam, At April-July7400 8000 8300 116 8600 9200
June-July3410 4010 4310 115 4610 5210


Gunnison 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
Taylor
Taylor Park Res April-July103 106 109 110 114 119
June-July61 64 67 108 72 77
Almont April-July167 171 175 113 181 187
June-July95 99 103 110 109 115
East
Almont April-July215 220 225 124 230 240
June-July116 121 126 119 131 141
Gunnison
Gunnison, Nr April-July440 445 455 123 470 480
June-July235 240 250 116 265 275
Tomichi Ck
Gunnison April-July100 105 109 147 113 116
June-July42 47 51 138 55 58
Lake Fork
Gateview April-July127 133 138 112 143 151
June-July85 91 96 119 101 109
Gunnison
Blue Mesa Res April-July810 825 840 124 855 880
June-July420 435 450 118 465 490
Morrow Point Res April-July875 890 905 122 920 945
June-July455 470 485 120 500 525
Crystal Res April-July940 980 995 119 1010 1040
June-July490 530 545 121 560 585
Muddy Ck
Paonia Res, Bardine, Nr March-June64 66 68 71 70 73
April-July58 60 62 64 64 67
June-June11 13 15 65 17 20
June-July15 17 19 66 21 24
Nf Gunnison
Somerset, Nr April-July245 250 255 86 260 265
June-July83 89 93 82 98 103
Surface Ck
Cedaredge April-July12.1 12.6 13.1 78 15.6 16.1
June-July3 3.5 4 53 6.5 7
Uncompahgre
Ridgway Res April-July91 95 98 97 104 109
June-July59 63 66 102 72 77
Colona April-July123 126 131 96 137 146
June-July75 78 83 102 89 98
Delta April-July108 111 115 102 121 131
June-July52 55 59 104 65 75
Gunnison
Grand Junction, Nr April-July1540 1550 1570 106 1610 1640
June-July740 755 775 112 815 840


Dolores 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
Dolores
Dolores April-July275 280 285 116 290 300
June-July84 90 95 103 100 111
Mcphee Res April-July310 320 325 110 330 340
June-July87 94 100 103 107 117
San Miguel
Placerville, Nr April-July114 118 121 95 126 132
June-July67 71 74 99 79 85
Dolores
Cisco, Nr April-July510 515 520 92 535 550
June-July180 185 189 103 205 220


San Juan 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
San Juan
Pagosa Springs April-July215 220 225 105 230 240
June-July71 74 78 81 84 92
Carracas, Nr April-July380 385 390 103 395 405
June-July116 120 125 79 132 140
Navajo Res, Archuleta, Nr April-July685 700 710 97 735 760
June-July186 200 210 72 235 260
Farmington April-July1010 1030 1040 95 1080 1110
June-July330 345 355 76 395 425
Bluff, Nr April-July1040 1050 1070 97 1110 1150
June-July315 330 345 77 390 425
Rio Blanco
Pagosa Springs, Nr, Blanco Dam, Blo April-July52 54 56 104 58 61
June-July14 16 17.5 76 20 23
Navajo
Chromo, Nr, Oso Div Dam, Blo April-July63 67 69 106 73 76
June-July19 23 25 83 29 32
Piedra
Arboles, Nr April-July196 200 205 98 210 215
June-July55 59 63 85 69 74
Los Pinos
Vallecito Res, Bayfield, Nr April-July195 200 205 106 215 225
June-July83 88 93 94 101 113
Animas
Durango April-July370 380 385 93 400 425
June-July172 180 187 85 200 225
Florida
Lemon Res, Durango, Nr April-July46 49 51 93 53 59
June-July19 22 24 89 26 32
La Plata
Hesperus April-July25 27 28 122 30 31
June-July9 11 12 141 14 15
Mancos
Mancos, Nr April-July35 36 38 123 39 41
June-July11 12 14 135 15 17

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 129.5 79 38 251.9 154 164.0 344.8
untitled Big Sandy
Big Sandy Res, Farson, Nr 38.4 131 100 34.0 116 29.4 38.3
Blacks Fork
Meeks Cabin 28.8 115 96 25.2 101 24.9 29.9
untitled Ef Smiths Fork
Stateline Res, Robertson,nr 14.1 125 102 11.9 106 11.3 13.9
untitled Green
Flaming Gorge Res, Flaming Gorge Dam, At 3202.9 104 85 3427.2 112 3071.5 3749.0
untitled Strawberry
Solider Springs,nr 927.5 130 84 828.7 116 716.0 1105.9
Starvation Res, Duchesne, Nr 141.0 91 85 163.9 106 154.8 165.3
untitled Rock Ck
Upper Stillwater Res 11.1 71 35 6.5 42 15.7 31.4
untitled Lake Fork
Moon Lake Res, Mtn Home, Nr 31.2 109 85 23.6 83 28.6 36.5
untitled Big Brush Ck
Red Fleet Res, Vernal, Nr 24.6 105 96 25.7 110 23.4 25.7
untitled Price
Scofield Res, Scofield, Nr 64.5 133 98 25.8 53 48.5 65.8
untitled Seeley Ck
Joes Vly Res, Orangeville, Nr 50.1 97 80 42.8 83 51.6 62.5
untitled Huntington Ck
Electric Lake 30.6 129 97 21.8 91 23.8 31.5
untitled
TOTAL 4694.2 108 82 4889.1 112 4363.6 5700.4


Upper Colorado 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 Colorado
Lake Granby, Granby, Nr 451.6 124 92 437.3 120 363.6 490.3
untitled Willow Ck
Willow Ck Res, Granby, Nr 9.4 106 103 8.7 97 8.9 9.1
untitled Williams Fork
Williams Fork Res, Parshall, Nr 82.5 113 85 86.1 118 73.0 96.9
untitled Muddy Ck
Wolford Mountain Reservoir 67.2 112 102 67.0 112 59.9 66.0
untitled Blue
Dillon Res 232.6 100 92 235.8 101 232.7 254.0
Green Mtn Res 90.8 101 62 97.0 108 89.8 146.9
untitled Homestake Ck
Homestake Res 29.7 120 69 38.2 154 24.8 43.0
untitled Frying Pan
Ruedi Res, Basalt, Nr 78.2 100 77 76.9 99 78.0 102.0
untitled Plateau Ck
Vega Res, Collbran, Nr 33.9 110 103 34.3 111 30.8 32.9
untitled Taylor
Taylor Park Res 84.3 113 79 76.7 103 74.7 106.2
untitled Gunnison
Blue Mesa Res 596.8 104 72 571.6 99 575.3 829.5
Morrow Point Res 108.8 96 93 99.0 87 113.2 117.0
Crystal Res 19.0 114 109 17.0 102 16.7 17.5
untitled Muddy Ck
Paonia Res, Bardine, Nr 12.0 77 72 7.1 46 15.7 16.7
untitled Uncompahgre
Ridgway Res 64.8 92 78 61.8 87 70.7 83.0
untitled Dolores
Mcphee Res 367.1 106 96 366.5 105 347.8 381.1
untitled
TOTAL 2328.7 107 83 2280.8 105 2175.6 2792.1
Colorado
Lake Powell 13667.1 75 56 12123.2 67 18186.3 24322.0
untitled
TOTAL 13667.1 75 56 12123.2 67 18186.3 24322.0


San Juan 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 Los Pinos
Vallecito Res, Bayfield, Nr 109.1 109 87 120.6 120 100.5 125.4
untitled San Juan
Navajo Res, Archuleta, Nr 1536.0 107 91 1549.4 108 1429.7 1696.0
untitled Florida
Lemon Res, Durango, Nr 36.0 112 90 35.0 109 32.1 39.8
untitled
TOTAL 1681.1 108 90 1705.0 109 1562.3 1861.2

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