Green Water Supply Outlook, April 1, 2019

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




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Yampa/White Basin Conditions




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Duchesne Basin Conditions




Snow Water Equivalent in Percent of Median.
* Percent usable capacity, not percent average contents.
Click for multi-month Graph.

Lower Green Basin Conditions




Snow Water Equivalent in Percent of Median.
* 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		70%
Exceedance
Volume		50%
Exceedance
Volume		Percent
Average		30%
Exceedance
Volume		10%
Exceedance
Volume
Green
Daniel, Nr, Warren Bridge, At April-July155 176 205 84 230 250
Pine Ck
Fremont Lk, Abv April-July75 88 95 97 103 110
New Fork
Big Piney, Nr April-July240 285 330 93 375 425
Green
Fontenelle Res, Fontenelle Nr April-July475 525 630 87 730 830
Big Sandy
Farson, Nr April-July35 44 49 94 58 66
Green
Green River, Wy, Nr April-July495 550 650 89 790 910
Hams Fork
Frontier, Nr, Pole Ck, Blo April-July28 30 38 70 49 59
Viva Naughton Res April-July37 41 50 68 65 82
Blacks Fork
Robertson, Nr April-July70 82 87 98 99 114
Ef Smiths Fork
Stateline Res, Robertson,nr April-July22 25 27 104 30 34
Green
Flaming Gorge Res, Flaming Gorge Dam, At April-July635 710 830 85 1020 1280


Yampa/White 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
Yampa
Stagecoach Rsvr, Abv April-July19 21 23 100 28 37
Steamboat Springs April-July210 240 275 106 310 345
Elk
Milner, Nr April-July280 335 360 113 405 435
Elkhead Ck
Long Gulch, Abv, Hayden, Nr April-July50 66 70 96 79 93
Yampa
Maybell, Nr April-July800 935 1030 110 1150 1280
Little Snake
Slater, Nr April-July109 142 156 100 167 200
Dixon, Nr April-July240 325 355 103 395 480
Lily, Nr April-July240 330 370 107 405 515
Yampa
Deerlodge Park April-July1020 1280 1400 113 1540 1780
White
Meeker, Nr April-July230 260 285 102 305 350
Watson, Nr April-July250 280 310 111 330 405


Duchesne 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
Big Brush Ck
Vernal, Nr, Red Fleet Res, Abv April-July14.4 17.6 20 95 23 30
Ashley Ck
Vernal, Nr April-July36 44 50 100 55 75
West Fork Duchesne
Vat Diversion, Blo April-July22 24 26 140 28 33
Duchesne
Tabiona, Nr April-July110 121 130 120 138 154
Rock Ck
Upper Stillwater Res April-July75 83 90 122 99 115
South Fork Rock Ck
Docs Div, Blo April-July7.5 8.6 9.2 126 10 11.7
Rock Ck
Mountain Home, Nr April-July88 100 107 122 118 137
Currant Ck
Currant Ck Res April-July25 28 31 155 34 39
Strawberry
Solider Springs,nr April-July76 85 96 135 108 119
Starvation Res, Duchesne, Nr April-July140 160 180 161 198 225
Duchesne
Duchesne, Nr, Knight Div, Abv April-July190 220 230 119 245 285
Lake Fork
Moon Lake Res, Mtn Home, Nr April-July61 73 78 118 86 99
Yellowstone
Altonah, Nr April-July55 68 72 118 78 97
Whiterocks
Whiterocks, Nr April-July40 49 55 102 61 77
Uinta
Neola, Nr April-July67 80 89 120 96 122
Duchesne
Myton April-July320 400 440 133 480 570
Randlett, Nr April-July370 445 500 130 540 675


Lower Green 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
White
Blo Tabbyune Ck, Soldier Summit, Nr April-July20 23 26 168 28 33
Fish Ck
Scofield, Nr, Reservoir, Abv April-July38 43 47 157 51 57
Price
Scofield Res, Scofield, Nr April-July52 60 68 166 72 85
Green
Green River, Ut April-July2600 2950 3250 110 3640 4200
Huntington Ck
Electric Lake April-July19 21 23 173 26 30
Power Plant, Blo April-July55 64 67 168 76 85
Seeley Ck
Joes Vly Res, Orangeville, Nr April-July60 71 75 134 80 95
Ferron Ck
Ferron, Nr April-July43 50 55 145 59 71
Muddy Ck
Emery, Nr April-July17.1 22 24 121 27 33

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 95.1 78 28 117.4 96 121.7 344.8
untitled Big Sandy
Big Sandy Res, Farson, Nr 17.6 90 46 33.4 170 19.6 38.3
Blacks Fork
Meeks Cabin 6.8 51 23 12.2 92 13.4 29.9
untitled Ef Smiths Fork
Stateline Res, Robertson,nr 4.2 76 30 6.3 115 5.5 13.9
untitled Green
Flaming Gorge Res, Flaming Gorge Dam, At 3185.0 105 85 3184.3 105 3021.3 3749.0
untitled Strawberry
Solider Springs,nr 860.5 130 78 935.6 141 663.7 1105.9
Starvation Res, Duchesne, Nr 143.5 96 87 164.9 110 149.7 165.3
untitled Rock Ck
Upper Stillwater Res 2.2 48 7 9.0 201 4.5 31.4
untitled Lake Fork
Moon Lake Res, Mtn Home, Nr 15.5 57 42 26.8 98 27.3 36.5
untitled Big Brush Ck
Red Fleet Res, Vernal, Nr 13.3 70 52 21.1 111 19.0 25.7
untitled Price
Scofield Res, Scofield, Nr 28.6 93 43 53.7 174 30.9 65.8
untitled Seeley Ck
Joes Vly Res, Orangeville, Nr 30.0 75 48 45.9 115 40.0 62.5
untitled Huntington Ck
Electric Lake -9999.0 -99 -99 23.3 127 18.3 31.5
untitled
TOTAL 4402.2 107 78 4633.9 112 4116.6 5669.0

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: Ashley Nielson