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.San Juan Water Supply Outlook, January 1, 2009

San Juan Water Supply Outlook, January 1, 2009


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

Contents

San Juan Summary

-Model Soil Moisture/Observed Streamflow...Soil moisture for most of the upper basins in the San Juan were below average in the fall. This was most likely due to limited monsoonal precipitation over the summer months. Observed streamflow for the month of December was mostly below average for the San Juan.

-Snowpack/Precipitation...Snowpack above Navajo Reservoir is currently 130 percent of average while the Animas was 135 percent. Precipitation over the San Juan Basin for December was much above average with 220 percent. Seasonal average precipitation for the San Juan Basin increased to 115 percent.

-Short Term Precipitation Forecast...The forecast models through next week keep the San Juan Basin relatively dry with near average temperatures.

-General Discussion...The current snowpack and statistical forecast suggest the April-July forecast of 115 to 120 percent of average. However, the ESP guidance suggests a forecast of around 110 percent of average due to lower than average soil moisture. The CPC guidance continues to show the possibility of increased chances of below average precipitation for January through March across the San Juan Basin.



*Median of forecasts within each basin.


San Juan Basin Conditions




* 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: Tracy Cox