San Juan Water Supply Outlook, June 1, 2008

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Prepared by Cox
NOAA, National Weather Service
Colorado Basin River Forecast Center
Salt Lake City, Utah


San Juan Summary

-Observed Streamflow...Streamflow for the month of May was average to above average for the San Juan Basin.

-Snowpack/Precipitation...Snowpack above Navajo Reservoir dropped to 105 percent of average. The Animas was below average for snowpack while the entire San Juan Basin dropped to 90 percent. Precipitation over the San Juan Basin for May was average with 100 percent. Seasonal average precipitation for the San Juan Basin dropped slightly to 105 percent.

-Short Term Precipitation Forecast...The forecast models through the next five days forecast 2 to 6 tenths of an inch of water over the San Juan Basin into Thursday evening. Relatively dry conditions will return this weekend into early next week. Temperatures over the next five days will be near to slightly below normal into Friday but rebound to above normal by early next week. The CPC forecast for days 6 through 10 have an increased chance for above normal temperatures and below normal precipitation.

-General Discussion...The current snowpack along with both statistical forecasts and ESP numbers suggest keeping the same forecast across all of the headwaters of the San Juan Basin. Near average precipitation across the San Juan Basin during the past month also reflect current thinking of generally keeping the same volume forecasts for the San Juan. CPC guidance for the remainder of June continues to show an increased chance of above normal temperatures and near to slightly below normal precipitation.

*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).

Precipitation Maps

Hydrologist: Cox