Upper Colorado Water Supply Outlook, February 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-July135 160 190 86 220 290
Willow Ck
Willow Ck Res, Granby, Nr April-July30 43 48 102 58 88
Fraser
Winter Park April-July16 18 21 108 23 26
Williams Fork
Williams Fork Res, Parshall, Nr April-July65 85 94 98 102 132
Muddy Ck
Wolford Mountain Reservoir April-July32 45 57 106 65 80
Blue
Dillon Res April-July120 146 165 101 177 225
Green Mtn Res April-July192 235 280 102 300 380
Colorado
Kremmling, Nr April-July575 730 820 95 925 1200
Eagle
Gypsum, Blo April-July230 275 320 96 375 480
Colorado
Dotsero, Nr April-July950 1170 1340 96 1500 1920
Frying Pan
Ruedi Res, Basalt, Nr April-July95 113 140 101 150 195
Roaring Fork
Glenwood Springs April-July500 600 700 101 750 965
Colorado
Glenwood Springs, Blo April-July1470 1800 2060 98 2250 2900
Cameo, Nr April-July1670 2000 2300 97 2500 3300
Plateau Ck
Cameo, Nr April-July95 115 135 109 145 205
Colorado
Cisco, Nr April-July3500 4000 4500 101 4900 6700
Lake Powell, Glen Cyn Dam, At April-July5000 6000 6700 94 7500 10300


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-July65 85 94 95 111 130
Almont April-July105 131 145 94 166 200
East
Almont April-July110 139 160 88 180 225
Gunnison
Gunnison, Nr April-July230 295 330 89 385 475
Tomichi Ck
Gunnison April-July44 60 75 101 88 120
Lake Fork
Gateview April-July100 115 135 110 153 185
Gunnison
Blue Mesa Res April-July460 575 640 95 710 930
Morrow Point Res April-July520 635 700 95 770 990
Crystal Res April-July605 720 785 94 855 1080
Muddy Ck
Paonia Res, Bardine, Nr March-June75 88 96 100 112 145
April-July0 0 0 0 0 0
Nf Gunnison
Somerset, Nr April-July210 255 290 98 335 410
Surface Ck
Cedaredge April-July11 15 17 101 20 25
Uncompahgre
Ridgway Res April-July82 100 112 111 122 155
Colona April-July100 135 150 109 170 220
Delta April-July80 110 125 111 145 210
Gunnison
Grand Junction, Nr April-July1000 1270 1450 98 1700 2200


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-July215 265 300 122 345 410
Mcphee Res April-July250 320 365 124 415 500
San Miguel
Placerville, Nr April-July100 130 147 115 165 195
Dolores
Cisco, Nr April-July440 600 700 124 800 1000

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 436.9 124 89 496.9 141 352.2 490.3
untitled Willow Ck
Willow Ck Res, Granby, Nr 8.3 104 91 8.9 112 8.0 9.1
untitled Williams Fork
Williams Fork Res, Parshall, Nr 78.0 122 80 78.5 123 63.8 96.9
untitled Muddy Ck
Wolford Mountain Reservoir 42.6 95 65 45.7 102 44.6 66.0
untitled Blue
Dillon Res 236.9 106 93 250.1 112 223.2 254.0
Green Mtn Res 67.9 84 46 75.0 93 81.1 146.9
untitled Homestake Ck
Homestake Res -9999.0 -99 -99 -9999.0 -99 31.9 43.0
untitled Frying Pan
Ruedi Res, Basalt, Nr 70.3 97 69 81.5 113 72.4 102.0
untitled Plateau Ck
Vega Res, Collbran, Nr 12.1 96 37 14.5 115 12.6 32.9
untitled Taylor
Taylor Park Res 69.7 104 66 79.0 118 66.9 106.2
untitled Gunnison
Blue Mesa Res 590.1 115 71 546.7 106 514.6 829.5
Morrow Point Res 109.6 98 94 110.6 99 111.4 117.0
Crystal Res 15.6 102 89 15.0 98 15.3 17.5
untitled Muddy Ck
Paonia Res, Bardine, Nr 1.1 26 6 0.7 18 4.2 16.7
untitled Uncompahgre
Ridgway Res 63.5 92 77 77.0 111 69.2 83.0
untitled Dolores
Mcphee Res 246.3 91 65 183.5 68 270.9 381.1
untitled
TOTAL 2048.8 107 75 2063.5 108 1910.6 2749.1
Colorado
Lake Powell 11426.7 66 47 11146.8 64 17338.2 24322.0
untitled
TOTAL 11426.7 66 47 11146.8 64 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