Upper Colorado Water Supply Outlook, June 1, 2015

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		50%
Exceedance
Volume		Percent
Average		10%
Exceedance
Volume
Colorado
Lake Granby, Granby, Nr April-July205 235 107 260
June-July135 166 114 190
Willow Ck
Willow Ck Res, Granby, Nr April-July36 41 87 47
June-July11 16 76 22
Fraser
Winter Park April-July17.2 20 103 23
June-July13.5 16.3 115 19
Williams Fork
Williams Fork Res, Parshall, Nr April-July89 100 104 107
June-July62 73 112 80
Muddy Ck
Wolford Mountain Reservoir April-July46 52 96 59
June-July12 18 93 25
Blue
Dillon Res April-July173 200 123 215
June-July130 157 143 170
Green Mtn Res April-July260 305 111 325
June-July185 230 125 250
Colorado
Kremmling, Nr April-July815 890 103 955
June-July510 585 111 650
Eagle
Gypsum, Blo April-July270 310 93 345
June-July175 215 100 250
Colorado
Dotsero, Nr April-July1240 1350 96 1460
June-July750 860 102 970
Frying Pan
Ruedi Res, Basalt, Nr April-July109 125 90 144
June-July75 91 102 110
Roaring Fork
Glenwood Springs April-July530 595 86 650
June-July375 440 97 495
Colorado
Glenwood Springs, Blo April-July1820 1980 94 2150
June-July1150 1310 101 1480
Cameo, Nr April-July1910 2110 89 2290
June-July1180 1380 97 1560
Plateau Ck
Cameo, Nr April-July64 75 60 85
June-July20 31 63 41
Colorado
Cisco, Nr April-July3160 3470 78 3850
June-July1790 2100 90 2480
Lake Powell, Glen Cyn Dam, At April-July4450 5000 70 6000
June-July2200 2750 73 3750


Gunnison Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		10%
Exceedance
Volume
Taylor
Taylor Park Res April-July75 86 87 108
June-July47 58 94 80
Almont April-July117 128 83 157
June-July75 86 91 115
East
Almont April-July114 129 71 157
May-July0 0 0 0
June-July62 77 73 105
Gunnison
Gunnison, Nr April-July245 280 76 325
June-July140 175 81 220
Tomichi Ck
Gunnison April-July58 66 89 79
June-July27 35 95 48
Lake Fork
Gateview April-July100 116 94 138
June-July72 88 109 110
Gunnison
Blue Mesa Res April-July520 570 84 670
June-July310 360 95 460
Morrow Point Res April-July565 615 83 715
June-July335 385 95 485
Crystal Res April-July625 675 81 775
June-July375 425 94 525
Muddy Ck
Paonia Res, Bardine, Nr March-June50 53 55 59
April-July31 50 52 70
June-June9 12 52 18
June-July11 14 48 20
Nf Gunnison
Somerset, Nr April-July154 165 56 187
June-July45 56 49 78
Surface Ck
Cedaredge April-July7.3 8 48 10.8
June-July1.5 2.2 29 5
Uncompahgre
Ridgway Res April-July61 73 72 85
June-July41 53 82 65
Colona April-July76 88 64 108
June-July50 62 77 82
Delta April-July69 76 67 90
June-July34 41 72 55
Gunnison
Grand Junction, Nr April-July905 1030 70 1210
June-July430 550 79 730


Dolores Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		10%
Exceedance
Volume
Dolores
Dolores April-July156 171 70 205
June-July65 80 87 115
Mcphee Res April-July165 180 61 215
June-July68 83 86 120
San Miguel
Placerville, Nr April-July84 104 81 122
June-July50 70 93 88
Dolores
Cisco, Nr April-July270 295 52 355
June-July125 150 82 210

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 505.2 139 103 383.2 105 363.6 490.3
untitled Willow Ck
Willow Ck Res, Granby, Nr 7.4 83 82 10.1 113 8.9 9.1
untitled Williams Fork
Williams Fork Res, Parshall, Nr 86.3 118 89 91.9 126 73.0 96.9
untitled Muddy Ck
Wolford Mountain Reservoir 52.5 88 80 68.4 114 59.9 66.0
untitled Blue
Dillon Res 224.8 97 88 202.9 87 232.7 254.0
Green Mtn Res 111.4 124 76 98.6 110 89.8 146.9
untitled Homestake Ck
Homestake Res 24.7 100 58 1.4 6 24.8 43.0
untitled Frying Pan
Ruedi Res, Basalt, Nr 84.3 108 83 81.0 104 78.0 102.0
untitled Plateau Ck
Vega Res, Collbran, Nr 32.3 105 98 34.4 112 30.8 32.9
untitled Taylor
Taylor Park Res 90.5 121 85 74.1 99 74.7 106.2
untitled Gunnison
Blue Mesa Res 652.8 113 79 675.6 117 575.3 829.5
Morrow Point Res 111.6 99 95 111.1 98 113.2 117.0
Crystal Res 16.7 100 95 18.7 112 16.7 17.5
untitled Muddy Ck
Paonia Res, Bardine, Nr 15.6 100 94 14.5 92 15.7 16.7
untitled Uncompahgre
Ridgway Res 72.3 102 87 60.9 86 70.7 83.0
untitled Dolores
Mcphee Res 264.8 76 69 270.0 78 347.8 381.1
untitled
TOTAL 2353.5 108 84 2197.0 101 2175.6 2792.1
Colorado
Lake Powell 11491.5 63 47 10764.5 59 18186.3 24322.0
untitled
TOTAL 11491.5 63 47 10764.5 59 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