Green Water Supply Outlook, February 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-July126 162 190 78 215 285
Pine Ck
Fremont Lk, Abv April-July60 70 82 84 87 104
New Fork
Big Piney, Nr April-July150 200 250 70 300 380
Green
Fontenelle Res, Fontenelle Nr April-July290 410 500 69 600 845
Big Sandy
Farson, Nr April-July25 36 41 79 48 64
Green
Green River, Wy, Nr April-July290 420 505 69 610 850
Hams Fork
Frontier, Nr, Pole Ck, Blo April-July23 28 34 63 41 59
Viva Naughton Res April-July29 35 44 59 56 92
Blacks Fork
Robertson, Nr April-July49 62 75 84 91 120
Ef Smiths Fork
Stateline Res, Robertson,nr April-July17.2 20 23 88 28 32
Green
Flaming Gorge Res, Flaming Gorge Dam, At April-July360 525 630 64 760 1230


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-July16 17.5 19.5 85 21 31
Steamboat Springs April-July160 205 235 90 265 330
Elk
Milner, Nr April-July210 265 310 97 345 405
Elkhead Ck
Long Gulch, Abv, Hayden, Nr April-July33 46 55 75 64 77
Yampa
Maybell, Nr April-July580 705 850 91 945 1170
Little Snake
Slater, Nr April-July82 114 135 87 154 185
Dixon, Nr April-July160 220 270 78 345 430
Lily, Nr April-July157 230 280 81 375 455
Yampa
Deerlodge Park April-July720 920 1130 91 1260 1550
White
Meeker, Nr April-July178 200 235 84 260 320
Watson, Nr April-July186 210 250 89 275 360


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-July10.1 13.6 16 76 19 27
Ashley Ck
Vernal, Nr April-July22 30 40 80 45 66
West Fork Duchesne
Vat Diversion, Blo April-July13 17.3 20 108 23 30
Duchesne
Tabiona, Nr April-July71 88 100 93 110 134
Rock Ck
Upper Stillwater Res April-July55 65 77 104 90 115
South Fork Rock Ck
Docs Div, Blo April-July5.1 6.4 7.5 103 9 10.5
Rock Ck
Mountain Home, Nr April-July65 76 91 103 107 136
Currant Ck
Currant Ck Res April-July14 19.2 23 115 26 36
Strawberry
Solider Springs,nr April-July38 55 68 96 89 108
Starvation Res, Duchesne, Nr April-July75 100 120 107 150 200
Duchesne
Duchesne, Nr, Knight Div, Abv April-July134 163 189 97 215 265
Lake Fork
Moon Lake Res, Mtn Home, Nr April-July45 58 64 97 76 98
Yellowstone
Altonah, Nr April-July38 52 60 98 68 85
Whiterocks
Whiterocks, Nr April-July25 35 43 80 48 71
Uinta
Neola, Nr April-July40 63 73 99 81 108
Duchesne
Myton April-July194 260 320 97 395 525
Randlett, Nr April-July205 270 335 87 420 605


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-July8.5 13.7 16.8 108 22 27
Fish Ck
Scofield, Nr, Reservoir, Abv April-July22 25 31 103 38 49
Price
Scofield Res, Scofield, Nr April-July31 35 41 100 52 68
Green
Green River, Ut April-July1730 2030 2400 81 2840 4000
Huntington Ck
Electric Lake April-July10.1 11.4 14 105 17.8 24
Power Plant, Blo April-July30 37 44 110 55 72
Seeley Ck
Joes Vly Res, Orangeville, Nr April-July39 51 57 102 64 88
Ferron Ck
Ferron, Nr April-July27 35 40 105 45 60
Muddy Ck
Emery, Nr April-July10.8 14.2 16.5 83 19.7 28

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 165.2 110 48 184.2 123 150.1 344.8
untitled Big Sandy
Big Sandy Res, Farson, Nr 30.8 186 80 23.5 142 16.6 38.3
Blacks Fork
Meeks Cabin 10.0 87 34 11.2 97 11.5 29.9
untitled Ef Smiths Fork
Stateline Res, Robertson,nr 6.0 108 43 6.4 114 5.6 13.9
untitled Green
Flaming Gorge Res, Flaming Gorge Dam, At 3259.2 107 87 3087.3 101 3050.5 3749.0
untitled Strawberry
Solider Springs,nr 930.6 141 84 776.1 118 659.9 1105.9
Starvation Res, Duchesne, Nr 158.6 114 96 142.2 102 138.8 165.3
untitled Rock Ck
Upper Stillwater Res 9.4 109 30 15.1 175 8.6 31.4
untitled Lake Fork
Moon Lake Res, Mtn Home, Nr 25.2 103 69 24.7 101 24.4 36.5
untitled Big Brush Ck
Red Fleet Res, Vernal, Nr 19.8 109 77 21.4 118 18.0 25.7
untitled Price
Scofield Res, Scofield, Nr 50.0 167 76 14.5 49 29.9 65.8
untitled Seeley Ck
Joes Vly Res, Orangeville, Nr 45.3 115 72 30.4 77 39.3 62.5
untitled Huntington Ck
Electric Lake 24.5 128 78 16.1 84 19.2 31.5
untitled
TOTAL 4734.6 113 83 4353.2 104 4172.4 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