Upper Colorado Water Supply Outlook, January 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-July135 170 215 98 245 330
Willow Ck
Willow Ck Res, Granby, Nr April-July25 38 50 106 58 85
Fraser
Winter Park April-July13 16 20 103 22 26
Williams Fork
Williams Fork Res, Parshall, Nr April-July60 78 95 99 107 135
Muddy Ck
Wolford Mountain Reservoir April-July24 38 52 96 66 85
Blue
Dillon Res April-July100 130 155 95 183 220
Green Mtn Res April-July165 215 260 95 300 380
Colorado
Kremmling, Nr April-July500 660 830 97 945 1240
Eagle
Gypsum, Blo April-July180 230 285 85 335 450
Colorado
Dotsero, Nr April-July790 1050 1300 93 1530 2030
Frying Pan
Ruedi Res, Basalt, Nr April-July73 97 120 86 140 190
Roaring Fork
Glenwood Springs April-July405 500 600 87 675 875
Colorado
Glenwood Springs, Blo April-July1220 1630 1920 91 2210 2900
Cameo, Nr April-July1380 1790 2120 90 2450 3300
Plateau Ck
Cameo, Nr April-July69 90 110 89 130 205
Colorado
Cisco, Nr April-July2500 3250 3900 88 4700 5800
Lake Powell, Glen Cyn Dam, At April-July4100 5330 6500 91 7750 9800


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-July62 76 81 82 102 137
Almont April-July95 117 125 81 160 220
East
Almont April-July105 135 158 87 188 270
Gunnison
Gunnison, Nr April-July220 285 310 84 400 575
Tomichi Ck
Gunnison April-July37 54 66 89 74 105
Lake Fork
Gateview April-July70 92 108 88 124 150
Gunnison
Blue Mesa Res April-July425 500 575 85 700 925
Morrow Point Res April-July475 550 625 84 750 975
Crystal Res April-July550 625 700 84 825 1050
Muddy Ck
Paonia Res, Bardine, Nr March-June55 68 83 86 90 120
April-July53 67 82 85 90 120
Nf Gunnison
Somerset, Nr April-July180 215 255 86 300 400
Surface Ck
Cedaredge April-July10 15 17 101 21 28
Uncompahgre
Ridgway Res April-July61 81 88 87 105 128
Colona April-July74 100 114 83 140 185
Delta April-July49 75 88 78 117 160
Gunnison
Grand Junction, Nr April-July950 1100 1250 84 1580 1930


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-July170 200 240 98 285 345
Mcphee Res April-July200 235 285 97 335 425
San Miguel
Placerville, Nr April-July75 95 110 86 130 165
Dolores
Cisco, Nr April-July320 390 500 88 580 815

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 453.9 121 93 468.3 125 375.1 490.3
untitled Willow Ck
Willow Ck Res, Granby, Nr 7.8 102 86 7.9 104 7.6 9.1
untitled Williams Fork
Williams Fork Res, Parshall, Nr 75.8 114 78 79.3 119 66.5 96.9
untitled Muddy Ck
Wolford Mountain Reservoir 51.1 113 77 43.5 97 45.1 66.0
untitled Blue
Dillon Res 228.4 101 90 236.6 104 226.9 254.0
Green Mtn Res 72.4 81 49 70.3 78 89.8 146.9
untitled Homestake Ck
Homestake Res -9999.0 -99 -99 41.4 126 32.9 43.0
untitled Frying Pan
Ruedi Res, Basalt, Nr 69.6 91 68 71.9 94 76.8 102.0
untitled Plateau Ck
Vega Res, Collbran, Nr 11.1 93 34 11.2 94 12.0 32.9
untitled Taylor
Taylor Park Res 69.2 102 65 69.8 103 68.1 106.2
untitled Gunnison
Blue Mesa Res 592.5 108 71 624.5 114 549.9 829.5
Morrow Point Res 109.4 98 93 112.2 101 111.6 117.0
Crystal Res 16.5 108 94 15.3 99 15.4 17.5
untitled Muddy Ck
Paonia Res, Bardine, Nr 1.6 38 10 1.1 25 4.2 16.7
untitled Uncompahgre
Ridgway Res 62.1 90 75 62.6 91 68.8 83.0
untitled Dolores
Mcphee Res 293.1 109 77 243.8 90 270.1 381.1
untitled
TOTAL 2114.6 106 77 2159.7 107 1987.9 2749.1
Colorado
Lake Powell 11796.9 66 49 11826.6 67 17744.8 24322.0
untitled
TOTAL 11796.9 66 49 11826.6 67 17744.8 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