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, March 1, 2009

Green Water Supply Outlook, March 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 February was 75 percent of average.

-Snowpack/Precipitation...In the Upper Green Basin, February precipitation was 75 percent of average. The basinwide to date snowpack condition is 85 percent of average with individual Snotel stations ranging from 48 to 102 percent of average.

-General Discussion...National Weather Service models suggest near to slightly above normal precipitation for the next 7-10 days. Beyond that the 30 Day CPC guidance shows equal chances for above, normal, or below precipitation. The 90 Day CPC guidance is for below normal precipitation. The antecedent soil moisture conditions will not change prior to runoff. 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 February was above average.

-Snowpack/Precipitation...Currently, the Yampa and White River basin has the highest snowpack conditions within the Green, with 75 percent of the Snotel stations having values greater than 110 percent of average on March 1st. February precipitation was only 85 percent of average.

-General Discussion...National Weather Service models suggest near to slightly above normal precipitation for the next 7-10 days. Beyond that the 30 Day CPC guidance shows equal chances for above, normal, or below precipitation. The 90 Day CPC guidance is for below normal precipitation. April through July forecast runoff volumes for the Yampa and White Basins ranged from 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 February was below average.

-Snowpack/Precipitation...The snowpack condition in the Duchesne Basin on March 1st is same as on the 1st of the last two months (January and February) at 85 percent of average, with 78 percent of the Snotel stations located in in the basin reporting below average conditions. February precipitation was 95 percent of average.

-General Discussion...National Weather Service models suggest near to slightly above normal precipitation for the next 7-10 days. Beyond that the 30 Day CPC guidance shows equal chances for above, normal, or below precipitation. The 90 Day CPC guidance is for below normal 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 February was below average.

-Snowpack/Precipitation...The Lower Green Basin snowpack condition was 80 percent of average on March 1st. February precipitation was 95 percent of average.

-General Discussion...National Weather Service models suggest near to slightly above normal precipitation for the next 7-10 days. Beyond that the 30 Day CPC guidance shows equal chances for above, normal, or below precipitation. The 90 Day CPC guidance is for below normal precipitation. Forecasts at this time, are now all 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