Upper Colorado Water Supply Outlook, March 1, 2019

Note: This publication is scheduled for revision. If you have feedback on content, format, or publication frequency, please contact us.
Prepared by Cody Moser, 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-July160 190 225 102 260 305
Willow Ck
Willow Ck Res, Granby, Nr April-July34 42 52 111 62 80
Fraser
Winter Park April-July14.5 17 19.5 101 22 24
Williams Fork
Williams Fork Res, Parshall, Nr April-July68 80 94 98 106 124
Muddy Ck
Wolford Mountain Reservoir April-July44 52 62 115 72 88
Blue
Dillon Res April-July135 160 180 110 200 220
Green Mtn Res April-July215 255 290 105 325 365
Colorado
Kremmling, Nr April-July660 780 900 105 1020 1210
Eagle
Gypsum, Blo April-July265 310 360 107 400 465
Colorado
Dotsero, Nr April-July1110 1280 1480 106 1700 2000
Frying Pan
Ruedi Res, Basalt, Nr April-July100 125 145 104 160 182
Roaring Fork
Glenwood Springs April-July530 620 700 101 780 880
Colorado
Glenwood Springs, Blo April-July1700 1980 2220 105 2520 2960
Cameo, Nr April-July1900 2220 2550 108 2850 3350
Plateau Ck
Cameo, Nr April-July120 145 165 133 185 210
Colorado
Cisco, Nr April-July3700 4300 4800 108 5300 6100
Lake Powell, Glen Cyn Dam, At April-July5300 6610 7300 102 8100 10700


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-July80 89 102 103 112 135
Almont April-July130 144 162 105 176 220
East
Almont April-July150 175 195 107 215 255
Gunnison
Gunnison, Nr April-July310 355 400 108 430 545
Tomichi Ck
Gunnison April-July50 68 80 108 91 121
Lake Fork
Gateview April-July94 119 135 110 155 185
Gunnison
Blue Mesa Res April-July570 660 740 110 820 1020
Morrow Point Res April-July640 730 810 109 890 1090
Crystal Res April-July725 815 895 107 975 1170
Muddy Ck
Paonia Res, Bardine, Nr March-June75 83 94 98 112 130
April-July76 84 95 98 113 131
Nf Gunnison
Somerset, Nr April-July240 260 290 98 320 410
Surface Ck
Cedaredge April-July17 20 23 137 25 28
Uncompahgre
Ridgway Res April-July66 88 98 97 105 136
Colona April-July89 120 130 95 145 195
Delta April-July59 90 105 93 120 175
Gunnison
Grand Junction, Nr April-July1180 1400 1520 103 1670 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-July190 240 275 112 300 375
Mcphee Res April-July230 290 330 112 360 480
San Miguel
Placerville, Nr April-July82 109 120 94 140 168
Dolores
Cisco, Nr April-July410 540 600 106 680 885

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 363.3 109 74 463.8 140 332.0 490.3
untitled Willow Ck
Willow Ck Res, Granby, Nr 8.5 103 93 8.2 99 8.2 9.1
untitled Williams Fork
Williams Fork Res, Parshall, Nr 65.5 105 68 66.3 106 62.4 96.9
untitled Muddy Ck
Wolford Mountain Reservoir 33.7 76 51 54.2 122 44.2 66.0
untitled Blue
Dillon Res 179.1 82 70 238.9 109 219.3 254.0
Green Mtn Res 52.7 72 36 68.3 93 73.5 146.9
untitled Homestake Ck
Homestake Res 33.6 109 78 41.0 134 30.7 43.0
untitled Frying Pan
Ruedi Res, Basalt, Nr 56.5 83 55 67.1 99 67.9 102.0
untitled Plateau Ck
Vega Res, Collbran, Nr 6.9 52 21 11.5 87 13.2 32.9
untitled Taylor
Taylor Park Res 59.6 91 56 72.3 110 65.7 106.2
untitled Gunnison
Blue Mesa Res 247.7 51 30 547.1 113 482.2 829.5
Morrow Point Res 107.2 96 92 108.4 98 111.1 117.0
Crystal Res 15.6 99 89 16.1 102 15.8 17.5
untitled Muddy Ck
Paonia Res, Bardine, Nr 4.1 89 25 3.6 78 4.7 16.7
untitled Uncompahgre
Ridgway Res 46.9 68 57 61.6 89 69.4 83.0
untitled Dolores
Mcphee Res 167.3 61 44 284.1 104 272.3 381.1
untitled
TOTAL 1448.2 77 52 2112.7 113 1872.6 2792.1
Colorado
Lake Powell 9260.7 54 38 13345.8 78 17054.6 24322.0
untitled
TOTAL 9260.7 54 38 13345.8 78 17054.6 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: Cody Moser, Greg Smith