Upper Colorado Water Supply Outlook, February 1, 2017

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-July180 220 250 114 280 365
Willow Ck
Willow Ck Res, Granby, Nr April-July43 55 65 138 85 110
Fraser
Winter Park April-July16 19 23 119 25 29
Williams Fork
Williams Fork Res, Parshall, Nr April-July85 105 115 120 130 165
Muddy Ck
Wolford Mountain Reservoir April-July35 50 62 115 75 90
Blue
Dillon Res April-July140 175 195 120 215 255
Green Mtn Res April-July240 295 330 120 360 450
Colorado
Kremmling, Nr April-July750 950 1040 121 1210 1550
Eagle
Gypsum, Blo April-July260 320 370 110 410 525
Colorado
Dotsero, Nr April-July1200 1480 1650 118 1870 2370
Frying Pan
Ruedi Res, Basalt, Nr April-July105 130 160 115 175 220
Roaring Fork
Glenwood Springs April-July600 725 800 116 860 1070
Colorado
Glenwood Springs, Blo April-July1840 2200 2450 116 2700 3500
Cameo, Nr April-July2100 2550 2780 118 3000 4000
Plateau Ck
Cameo, Nr April-July105 130 150 121 165 215
Colorado
Cisco, Nr April-July4000 5000 5500 124 6000 7550
Lake Powell, Glen Cyn Dam, At April-July6600 8300 9600 134 10500 13500


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-July99 115 128 129 145 165
Almont April-July157 188 210 135 230 265
East
Almont April-July185 220 245 135 260 315
Gunnison
Gunnison, Nr April-July380 460 510 138 560 660
Tomichi Ck
Gunnison April-July75 92 105 142 120 170
Lake Fork
Gateview April-July109 128 150 122 167 195
Gunnison
Blue Mesa Res April-July690 820 925 137 990 1250
Morrow Point Res April-July785 915 1020 138 1090 1350
Crystal Res April-July915 1050 1150 138 1220 1480
Muddy Ck
Paonia Res, Bardine, Nr March-June95 110 118 123 133 167
April-July96 111 119 123 134 168
Nf Gunnison
Somerset, Nr April-July285 325 355 120 380 480
Surface Ck
Cedaredge April-July15 18 21 125 25 31
Uncompahgre
Ridgway Res April-July85 110 118 117 126 160
Colona April-July114 142 158 115 171 225
Delta April-July82 120 133 118 145 200
Gunnison
Grand Junction, Nr April-July1480 1720 1920 130 1980 2650


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-July280 335 370 151 400 475
Mcphee Res April-July320 395 440 149 480 570
San Miguel
Placerville, Nr April-July109 142 155 121 173 210
Dolores
Cisco, Nr April-July550 720 800 142 900 1110

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 424.3 120 87 436.9 124 352.2 490.3
untitled Willow Ck
Willow Ck Res, Granby, Nr 8.2 104 91 8.3 104 8.0 9.1
untitled Williams Fork
Williams Fork Res, Parshall, Nr 74.4 117 77 78.0 122 63.8 96.9
untitled Muddy Ck
Wolford Mountain Reservoir 50.7 114 77 42.6 95 44.6 66.0
untitled Blue
Dillon Res 224.0 100 88 236.9 106 223.2 254.0
Green Mtn Res 67.2 83 46 67.9 84 81.1 146.9
untitled Homestake Ck
Homestake Res -9999.0 -99 -99 41.3 129 31.9 43.0
untitled Frying Pan
Ruedi Res, Basalt, Nr 67.8 94 67 70.3 97 72.4 102.0
untitled Plateau Ck
Vega Res, Collbran, Nr 11.9 95 36 12.1 96 12.6 32.9
untitled Taylor
Taylor Park Res 69.5 104 65 69.7 104 66.9 106.2
untitled Gunnison
Blue Mesa Res 586.6 114 71 590.1 115 514.6 829.5
Morrow Point Res 111.7 100 95 109.6 98 111.4 117.0
Crystal Res 16.2 105 92 15.6 102 15.3 17.5
untitled Muddy Ck
Paonia Res, Bardine, Nr 1.6 38 10 1.1 26 4.2 16.7
untitled Uncompahgre
Ridgway Res 63.8 92 77 63.5 92 69.2 83.0
untitled Dolores
Mcphee Res 294.4 109 77 246.3 91 270.9 381.1
untitled
TOTAL 2072.4 108 75 2090.0 108 1910.6 2749.1
Colorado
Lake Powell 11359.3 66 47 11426.7 66 17338.2 24322.0
untitled
TOTAL 11359.3 66 47 11426.7 66 17338.2 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