Upper Colorado Water Supply Outlook, June 1, 2016

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

Contents

Upper Colorado Summary




*Median of forecasts within each basin.


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.


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-July185 200 210 95 225 235
June-July113 128 140 97 153 163
Willow Ck
Willow Ck Res, Granby, Nr April-July47 50 54 115 57 60
June-July13.5 16.5 21 100 24 27
Fraser
Winter Park April-July18.5 20 21 108 22 24
June-July14.3 15.8 17 120 17.8 19.8
Williams Fork
Williams Fork Res, Parshall, Nr April-July93 98 102 106 105 115
June-July57 62 66 102 69 79
Muddy Ck
Wolford Mountain Reservoir April-July52 55 58 107 62 70
June-July15.7 18.7 22 114 26 34
Blue
Dillon Res April-July150 160 170 104 175 185
June-July110 120 130 118 135 145
Green Mtn Res April-July240 260 275 100 290 315
June-July163 183 198 108 215 240
Colorado
Kremmling, Nr April-July830 855 900 105 945 1000
June-July470 495 540 103 585 640
Eagle
Gypsum, Blo April-July275 300 315 94 330 350
June-July170 195 210 98 225 245
Colorado
Dotsero, Nr April-July1270 1340 1400 100 1470 1550
June-July725 795 855 102 925 1010
Frying Pan
Ruedi Res, Basalt, Nr April-July105 115 125 90 130 140
June-July72 82 92 103 97 107
Roaring Fork
Glenwood Springs April-July525 560 595 86 615 650
June-July350 385 420 92 440 475
Colorado
Glenwood Springs, Blo April-July1830 1940 2020 96 2080 2200
June-July1090 1200 1280 98 1340 1460
Cameo, Nr April-July1980 2110 2220 94 2320 2450
June-July1160 1290 1400 99 1500 1630
Plateau Ck
Cameo, Nr April-July110 115 125 101 130 145
June-July32 37 47 96 52 67
Colorado
Cisco, Nr April-July3550 3750 3900 88 4050 4250
June-July1800 2000 2150 92 2300 2500
Lake Powell, Glen Cyn Dam, At April-July5800 6100 6500 91 6800 7250
June-July2690 2990 3390 90 3690 4140


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-July79 81 83 84 88 90
June-July53 55 57 92 62 64
Almont April-July118 121 123 79 127 130
June-July77 80 82 87 86 89
East
Almont April-July134 138 141 77 144 148
June-July75 79 82 77 85 89
Gunnison
Gunnison, Nr April-July270 275 280 76 285 295
June-July165 170 175 81 180 190
Tomichi Ck
Gunnison April-July61 62 64 86 66 68
June-July27 28 30 81 32 34
Lake Fork
Gateview April-July107 110 113 92 117 123
June-July74 77 80 99 84 90
Gunnison
Blue Mesa Res April-July550 560 580 86 590 615
June-July315 325 345 91 355 380
Morrow Point Res April-July595 605 625 84 635 660
June-July335 345 365 90 375 400
Crystal Res April-July660 670 690 83 700 725
June-July375 385 405 90 415 440
Muddy Ck
Paonia Res, Bardine, Nr March-June71 74 75 78 76 78
April-July69 72 74 76 77 78
June-June12 15 16 70 17.5 19
June-July15 18 20 69 23 24
Nf Gunnison
Somerset, Nr April-July220 225 225 76 230 235
June-July76 81 84 74 88 92
Surface Ck
Cedaredge April-July10.5 11 11.5 68 12 13.5
June-July2 2.5 3 39 3.5 5
Uncompahgre
Ridgway Res April-July86 89 93 92 99 103
June-July58 61 65 100 71 75
Colona April-July116 119 123 90 130 136
June-July70 73 77 95 84 90
Delta April-July98 101 105 93 112 120
June-July45 48 52 91 59 67
Gunnison
Grand Junction, Nr April-July1160 1190 1210 82 1240 1260
June-July530 560 580 83 615 635


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-July205 210 215 88 220 230
June-July73 78 82 89 88 98
Mcphee Res April-July215 225 230 78 240 250
June-July70 77 84 87 96 105
San Miguel
Placerville, Nr April-July101 105 110 86 114 120
June-July63 67 72 96 76 82
Dolores
Cisco, Nr April-July400 405 415 73 425 440
June-July145 151 160 87 170 185

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).

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 437.3 120 89 505.2 139 363.6 490.3
untitled Willow Ck
Willow Ck Res, Granby, Nr 8.7 97 95 7.4 83 8.9 9.1
untitled Williams Fork
Williams Fork Res, Parshall, Nr 86.1 118 89 86.3 118 73.0 96.9
untitled Muddy Ck
Wolford Mountain Reservoir 67.0 112 102 52.5 88 59.9 66.0
untitled Blue
Dillon Res 235.8 101 93 224.8 97 232.7 254.0
Green Mtn Res 97.0 108 66 111.4 124 89.8 146.9
untitled Homestake Ck
Homestake Res 38.2 154 89 24.7 100 24.8 43.0
untitled Frying Pan
Ruedi Res, Basalt, Nr 76.9 99 75 84.3 108 78.0 102.0
untitled Plateau Ck
Vega Res, Collbran, Nr 34.3 111 104 32.3 105 30.8 32.9
untitled Taylor
Taylor Park Res 76.7 103 72 90.5 121 74.7 106.2
untitled Gunnison
Blue Mesa Res 571.6 99 69 652.8 113 575.3 829.5
Morrow Point Res 99.0 87 85 111.6 99 113.2 117.0
Crystal Res 17.0 102 97 16.7 100 16.7 17.5
untitled Muddy Ck
Paonia Res, Bardine, Nr 7.1 46 43 15.6 100 15.7 16.7
untitled Uncompahgre
Ridgway Res 61.8 87 74 72.3 102 70.7 83.0
untitled Dolores
Mcphee Res 366.5 105 96 264.8 76 347.8 381.1
untitled
TOTAL 2280.8 105 82 2353.5 108 2175.6 2792.1
Colorado
Lake Powell 12123.2 67 50 11491.5 63 18186.3 24322.0
untitled
TOTAL 12123.2 67 50 11491.5 63 18186.3 24322.0

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, Greg Smith