Upper Colorado Water Supply Outlook, January 1, 2023

Note: This publication is scheduled for revision. If you have feedback on content, format, or publication frequency, please contact us.
Prepared by Cody Moser, Ashley Nielson
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-July160 200 225 100 250 300
Willow Ck
Willow Ck Reservoir, Granby, Nr April-July30 46 60 120 72 90
Fraser
Winter Park April-July13.5 17 20 108 22 25
Williams Fork
Williams Fork Reservoir, Parshall April-July58 76 88 92 100 118
Muddy Ck
Wolford Mountain Reservoir April-July28 42 58 112 72 90
Blue
Dillon Reservoir April-July110 135 160 96 185 210
Green Mtn Reservoir April-July180 230 270 96 315 360
Colorado
Kremmling, Nr April-July580 745 880 101 1020 1210
Eagle
Gypsum, Blo April-July225 275 320 96 380 470
Colorado
Dotsero, Nr April-July950 1200 1420 101 1650 2000
Frying Pan
Ruedi Reservoir, Basalt, Nr April-July92 115 132 98 150 182
Roaring Fork
Glenwood Springs April-July470 560 635 97 750 960
Colorado
Glenwood Springs, Blo April-July1460 1800 2100 101 2450 3000
Cameo, Nr April-July1630 2000 2300 101 2700 3400
Cisco, Nr April-July3000 3600 4150 102 5000 6800
Lake Powell, Glen Cyn Dam, At April-July4440 5170 6700 105 8380 11530


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 Reservoir April-July75 86 97 103 111 149
Almont April-July120 138 152 103 176 245
East
Almont April-July119 153 166 94 215 275
Gunnison
Gunnison, Nr April-July245 315 335 96 440 585
Tomichi Ck
Gunnison April-July31 49 60 90 71 107
Lake Fork
Gateview April-July85 97 110 93 119 152
Gunnison
Blue Mesa Reservoir April-July460 535 605 95 725 985
Morrow Point Reservoir April-July505 585 655 95 795 1050
Crystal Reservoir April-July580 655 735 95 900 1170
Muddy Ck
Paonia Reservoir, Bardine, Nr April-July61 73 85 105 93 156
Nf Gunnison
Somerset, Nr April-July210 245 275 104 310 455
Surface Ck
Cedaredge April-July11.3 14.8 15.9 109 17.7 32
Uncompahgre
Ridgway Reservoir April-July68 83 90 98 102 122
Colona April-July82 105 113 94 131 163
Delta April-July61 83 90 95 101 149
Gunnison
Grand Junction, Nr April-July1000 1190 1300 98 1620 2180


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-July136 183 225 105 265 400
Mcphee Reservoir April-July163 215 260 102 325 495
San Miguel
Placerville, Nr April-July76 102 115 100 128 160
Dolores
Cisco, Nr April-July290 390 500 99 570 960

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 481.5 123 98 368.9 94 392.1 490.3
untitled Willow Ck
Willow Ck Reservoir, Granby, Nr 7.4 94 81 6.9 88 7.8 9.1
untitled Williams Fork
Williams Fork Reservoir, Parshall 45.6 65 47 62.5 89 69.9 96.9
untitled Muddy Ck
Wolford Mountain Reservoir 40.3 88 61 31.3 69 45.6 66.0
untitled Blue
Dillon Reservoir 210.9 93 83 196.4 86 227.3 254.0
Green Mtn Reservoir 83.9 102 57 65.0 79 82.6 146.9
untitled Homestake Ck
Homestake Reservoir 29.7 92 69 29.0 90 32.4 43.0
untitled Frying Pan
Ruedi Reservoir, Basalt, Nr 66.7 90 65 58.2 79 73.9 102.0
untitled Plateau Ck
Vega Reservoir, Collbran, Nr 8.9 75 27 5.5 46 12.0 32.9
untitled Taylor
Taylor Park Reservoir 66.3 96 62 58.7 85 68.9 106.2
untitled Gunnison
Blue Mesa Reservoir 290.2 54 35 230.9 43 536.0 827.9
Morrow Point Reservoir 102.9 93 88 105.7 96 110.1 117.0
Crystal Reservoir 16.6 109 94 16.1 106 15.1 17.5
untitled Muddy Ck
Paonia Reservoir, Bardine, Nr 1.1 47 6 0.7 30 2.3 16.7
untitled Uncompahgre
Ridgway Reservoir 67.8 101 82 64.6 96 67.0 83.0
untitled Dolores
Mcphee Reservoir 186.8 73 49 164.8 65 255.4 381.1
untitled
TOTAL 1706.5 85 61 1465.3 73 1998.4 2790.6
Colorado
Lake Powell 5530.5 37 23 6713.1 45 14835.5 24322.0
untitled
TOTAL 5530.5 37 23 6713.1 45 14835.5 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 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: Cody Moser, Ashley Nielson