Note: This publication is currently undergoing major revisions. The current publication will be replaced with a new publication based on stakeholder requirements and scientific advances. We expect to begin sharing details on this soon. If you have input on content, format, or publication frequency at any time, please contact us at cbrfc.webmasters@noaa.gov.Green Water Supply Outlook, February 1, 2009

Green Water Supply Outlook, February 1, 2009


Prepared by Bill Reed
NOAA, National Weather Service
Colorado Basin River Forecast Center
Salt Lake City, Utah
www.cbrfc.noaa.gov

Contents

Green Summary

November modeled soil moisture indicated much below and below average conditions for most of Green River Basin. (Click for November 1st image) This signal is incorporated in the ESP model guidance utilized by the CBRFC in generating our forecasts. At the time of this publication, seasonal precipitation is near normal for most of the region. Snowpack ranges from above average to below average in the major tributaries of the Green River.



*Median of forecasts within each basin.


Upper Green Basin Conditions

-Model Soil Moisture/Observed Streamflow...The November soil moisture conditions were much below average in the Upper Green Basin. Observed streamflow for the month of January was 90 percent of average.

-Snowpack/Precipitation...In the Upper Green Basin, January precipitation was 105 percent of average. The basinwide to date snowpack condition is 90 percent of average with individual Snotel stations ranging from 43 to 113 percent of average.

-General Discussion...The 30 Day and 90 Day CPC guidance shows equal chances for above, normal, or below precipitation. While the antecedent soil moisture conditions will not change prior to runoff, there is ample time to accumulate snow in the upper basin. April through July forecast indicate below average to average runoff volumes.



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

Yampa/White Basin Conditions

-Model Soil Moisture/Observed Streamflow...While soil moisture indicate drier than average Fall conditions in portions of this region, headwater basins had near average conditions. Therefore, soil moisture deficits are not adversely effecting model guidance as much as in other regions. Observed streamflow for the month of January was near average.

-Snowpack/Precipitation...Currently, the Yampa and White River basins has the highest snowpack conditions within the Green, with most Snotel stations having values greater than 115 percent of average values on February 1st. Observed streamflow for the month of January was near average.

-General Discussion...The 30 Day and 90 Day CPC guidance shows equal chances for above, normal, or below precipitation. April through July forecast runoff volumes for the Yampa and White Basins ranged from near average to above average.



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

Duchesne Basin Conditions

-Model Soil Moisture/Observed Streamflow...Fall soil conditions in the Duchesne were similar to the Upper Green with many basins indicating much below average conditions. Observed streamflow for the month of January was near average.

-Snowpack/Precipitation...The snowpack condition in the Duchesne Basin on February 1st is the same as January 1st at 85 percent of average. However, some Snotel stations located in the Eastern portion of the Uinta South slope continue to report below average conditions. January precipitation was 95 percent of average.

-General Discussion...The 30 Day and 90 Day CPC guidance shows equal chances for above, normal, or below precipitation. Forecasts range below average on the headwaters of the basin to much below average at downstream locations.



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

Lower Green Basin Conditions

-Model Soil Moisture/Observed Streamflow...The November soil moisture conditions were much below average in the Lower Green Basin. Observed streamflow for the month of January was near average.

-Snowpack/Precipitation...The Lower Green Basin snowpack condition was 85 percent of average on February 1st. January precipitation was 110 percent of average.

-General Discussion...The 30 Day and 90 Day CPC guidance shows equal chances for above, normal, or below precipitation. Forecasts remain at near average to below average.



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









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).

Reservoir Monthly Inflow Forecasts







Monthly Streamflows







Precipitation Maps








Hydrologist: Bill Reed