WSP06342

• 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: 10/1/1992
• Author: NOAA
• Title: 1992 Water Year in Review - 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. At best, adjusted flows will closely approximate natural or unimpaired flows.
However, not all upstream diversions or impoundments are measured, quantifiable or predictable.

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, U.S. Geological Survey and

local water district managers.

DEFINITIONS:
Acre-Foot:
The volume equal to 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
Greater than 130%

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

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

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

Above Average
II 1 -130%

Near Average
90- I 10%

Below Average
70-89%

Much below Average
Less than 70%

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, UT 841 16. [phone]

- IO-