Green Water Supply Outlook, May 1, 2013

Note: This publication is scheduled for revision. If you have feedback on content, format, or publication frequency, please contact us.
Prepared by Ashley Nielson
NOAA, National Weather Service
Colorado Basin River Forecast Center
Salt Lake City, Utah
www.cbrfc.noaa.gov

Contents

Green Summary




*Median of forecasts within each basin.


Upper Green Basin Conditions




* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Yampa/White Basin Conditions




* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Duchesne Basin Conditions




* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Lower Green Basin Conditions




* Percent usable capacity, not percent average contents.
Click for multi-month Graph.


Upper Green Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		10%
Exceedance
Volume
Green
Daniel, Nr, Warren Bridge, At April-July126 171 70 200
May-July115 160 71 190
Pine Ck
Fremont Lk, Abv April-July47 62 63 82
May-July46 61 64 81
New Fork
Big Piney, Nr April-July102 173 49 270
May-July94 165 50 260
Green
Fontenelle Res, Fontenelle Nr April-July240 380 52 505
May-July190 330 52 455
Big Sandy
Farson, Nr April-July17.6 30 58 45
May-July15 27 56 42
Green
Green River, Wy, Nr April-July225 365 50 500
May-July175 315 49 450
Hams Fork
Frontier, Nr, Pole Ck, Blo April-July22 33 61 42
May-July18 29 60 38
Viva Naughton Res April-July23 39 53 58
May-July15 31 50 50
Blacks Fork
Robertson, Nr April-July42 63 71 82
May-July40 61 72 80
Ef Smiths Fork
Stateline Res, Robertson,nr April-July13.6 18.4 71 25
May-July13 17.8 68 24
Green
Flaming Gorge Res, Flaming Gorge Dam, At April-July300 480 49 685
May-July230 410 49 610


Yampa/White Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		10%
Exceedance
Volume
Yampa
Stagecoach Rsvr, Abv April-July12.3 18.1 79 25
May-July7 12.8 80 20
Steamboat Springs April-July152 196 75 245
May-July135 179 81 230
Elk
Milner, Nr April-July185 240 75 305
May-July166 220 76 285
Elkhead Ck
Long Gulch, Abv, Hayden, Nr April-July28 42 58 58
May-July20 34 68 50
Yampa
Maybell, Nr April-July450 605 65 770
May-July380 535 69 700
Little Snake
Slater, Nr April-July61 93 60 126
May-July55 87 63 120
Savery, Nr April-July97 169 49 245
May-July83 155 53 230
Lily, Nr April-July96 173 50 250
May-July80 157 54 235
White
Meeker, Nr April-July134 176 63 230
May-July110 152 62 205
Watson, Nr April-July121 176 63 235
May-July100 155 66 210


Duchesne Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		10%
Exceedance
Volume
Big Brush Ck
Vernal, Nr, Red Fleet Res, Abv April-July12.1 14.2 68 18.6
May-July11.3 13.4 73 17.8
Ashley Ck
Vernal, Nr April-July24 33 66 43
May-July22 31 66 41
West Fork Duchesne
Vat Diversion, Blo April-July7 11.1 60 15.5
May-July6.4 10.5 61 14.9
Duchesne
Tabiona, Nr April-July53 72 67 92
May-July46 65 66 85
Rock Ck
Upper Stillwater Res April-July43 56 76 70
May-July41 54 76 68
South Fork Rock Ck
Docs Div, Blo April-July4.2 5.2 71 6.6
May-July3.9 4.9 71 6.3
Rock Ck
Mountain Home, Nr April-July55 67 76 83
May-July52 64 76 80
Currant Ck
Currant Ck Res April-July7.1 8.7 44 13
May-July5.8 7.4 43 11.7
Strawberry
Solider Springs,nr April-July11.9 18.9 34 29
May-July6.1 13.1 30 23
Starvation Res, Duchesne, Nr April-July26 40 36 60
May-July16 30 33 50
Duchesne
Duchesne, Nr, Knight Div, Abv April-July105 136 70 170
May-July94 125 70 159
Lake Fork
Moon Lake Res, Mtn Home, Nr April-July36 50 76 65
May-July34 48 76 63
Yellowstone
Altonah, Nr April-July33 45 74 56
May-July30 42 74 53
Whiterocks
Whiterocks, Nr April-July25 39 72 52
May-July23 37 73 50
Uinta
Neola, Nr April-July33 52 70 72
May-July31 50 70 70
Duchesne
Myton April-July97 149 45 205
May-July73 125 42 181
Randlett, Nr April-July108 160 42 215
May-July83 135 39 192


Lower Green Specific Site Forecasts (kaf)

Click site name for graph.
Forecast
Period		90%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		10%
Exceedance
Volume
White
Blo Tabbyune Ck, Soldier Summit, Nr April-July2.2 3.9 25 6.4
May-July1.5 3.2 27 5.7
Fish Ck
Scofield, Nr, Reservoir, Abv April-July14.3 17 57 22
May-July12.1 14.8 57 19.6
Price
Scofield Res, Scofield, Nr April-July17.9 22 54 29
May-July15.2 19 54 26
Green
Green River, Ut April-July1150 1540 52 2170
May-July975 1370 54 2000
Huntington Ck
Electric Lake April-July3.5 5.3 40 7.2
May-July2.7 4.5 38 6.4
Power Plant, Blo April-July17.3 19.7 49 26
May-July16 18.4 50 25
Seeley Ck
Joes Vly Res, Orangeville, Nr April-July18.8 25 45 33
May-July17 23 44 31
Ferron Ck
Ferron, Nr April-July13.7 19.5 51 28
May-July12.8 18.6 53 27
Muddy Ck
Emery, Nr April-July7.7 9.3 47 11.6
May-July7.1 8.7 48 11

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).

Green 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 Green
Fontenelle Res, Fontenelle Nr 128.1 102 37 160.1 128 125.0 344.8
untitled Big Sandy
Big Sandy Res, Farson, Nr 11.2 53 29 30.0 141 21.3 38.3
Blacks Fork
Meeks Cabin 10.1 62 34 29.5 179 16.5 29.9
untitled Ef Smiths Fork
Stateline Res, Robertson,nr 5.2 80 38 10.4 160 6.5 13.9
untitled Green
Flaming Gorge Res, Flaming Gorge Dam, At 3001.9 99 80 3205.1 105 3040.4 3749.0
untitled Strawberry
Solider Springs,nr 899.9 120 81 993.6 132 752.8 1105.9
Starvation Res, Duchesne, Nr 164.7 108 100 163.6 108 151.9 165.3
untitled Rock Ck
Upper Stillwater Res 6.5 226 21 2.9 102 2.9 31.4
untitled Lake Fork
Moon Lake Res, Mtn Home, Nr 13.7 50 38 28.0 101 27.6 36.5
untitled Big Brush Ck
Red Fleet Res, Vernal, Nr 15.0 75 58 24.7 123 20.1 25.7
untitled Price
Scofield Res, Scofield, Nr 32.3 98 49 54.6 165 33.0 65.8
untitled Seeley Ck
Joes Vly Res, Orangeville, Nr 33.7 85 54 52.4 132 39.6 62.5
untitled Huntington Ck
Electric Lake 19.3 103 61 24.9 133 18.7 31.5
untitled
TOTAL 4341.8 102 76 4779.9 112 4256.3 5700.4

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: Ashley Nielson