WSP11955

• File Number: 8210.137
• Description: Colorado River Basin-Colorado River Basin Organizations/Entities-Colorado River Forecast Committee
• State: CO
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 2/1/1993
• Author: NOAA
• Title: Water Supply Outlook - Colorado Basin River Forecast Center - Upper Colorado Report
• Water Supply Pro - Doc Type: Report/Study

AoDmONAL 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.

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. National Weather Service. It represents a coordinated effort between the National Weather
Service. Soil Conservation Service, Bureau of Reclamation, V.S, Geological Survey and local water
district managers,

DEFINITIONS:

Acre-Foot:
The volume equal 10 one acre covered one foot deep (43.560 cubic feet),

Average:
The arithmetic mean, The sum of the values divided by the number of values,

Categories:
Much above Average Above Average Near Average
130% or more III -130% 90-110%

Forecast Period:
The period from April I through July 31.

Median:
The middle value. One half of the observed values are higher and half of the values are lower than this,

Most Probable Forecast:
Given the current hydrometeorological conditions to date, this is the best estimate of what the runoff
volume will be this season,

Below Average
70-89%

Much below Average
70% or less

Reasonable Maximum Forecast:
Given the current hydrometeorological conditions, the seasonal runoff that has a ten percent (10%) chance
of being exceeded,

Reasonable Minimum Forecast:
Given the current hydrometeorological conditions, the seasonal runoff that has a ninety percent (90%)
chance of being exceeded.

Water Year:
The period from October I through September 30.

NOTE: Data used in this report are provisional and are subiect to revision.

For more information. or to be included on the mailing list, please contact:

Colorado Basin River Forecast Center. National Weather Service
337 N 2370 W. Salt Lake City, VT 84116. [phone]

Colorado Basin River Forecast Center - National Weather Service

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