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.Upper Colorado Water Supply Outlook, March 1, 2010

Upper Colorado Water Supply Outlook, March 1, 2010


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

Contents

Upper Colorado Summary




*Median of forecasts within each basin.


Upper Colorado Mainstem Basin Conditions

The following conditions influenced this month's forecasts:

Precipitation:
Seasonal October through February precipitation was near 85 percent of average in the Upper Colorado mainstem basin. February precipitation was near 100 percent of average.

Snow:
March 1st snow water equivalent was near 80 percent of average in the basin as a whole.
--- Upper Colorado basin snow water equivalent plot

Streamflow:
February streamflow was near 85 percent of average.

Soil Moisture:
Modeled soil moisture states were near average heading into the winter.

Climate Forecasts:
Climate forecasts were not a factor because there is not a strong correlation between El Nino conditions and winter precipitation in the Upper Colorado mainstem basin.

Forecast Summary:
Due to near normal February precipitation, many of the April through July streamflow volume forecasts did not change from last month. However, due to below average seasonal precipitation and snow water equivalent, these forecasts range between 55 and 118 percent of average with a median value of 75 percent.



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

Gunnison Basin Conditions

The following conditions influenced this month's forecasts:

Precipitation:
Seasonal October through February precipitation was 95 percent of average in the Gunnison basin. February precipitation was 125 percent of average.

Snow:
March 1st snow water equivalent was 95 percent of average in the Gunnison basin.
--- Gunnison basin snow water equivalent plot

Streamflow:
February streamflow was 85 percent of average.

Soil Moisture:
Modeled soil moisture states were below average heading into the winter.

Climate Forecasts:
Climate forecasts were not a factor because there is not a strong correlation between El Nino conditions and winter precipitation in the Gunnison basin.

Forecast Summary:
February precipitation throughout the Gunnison basin was 125% of average. However, February precipitation in the upper portions of the basin was near to below average. Therefore, the April through July volume forecast was lowered slightly by 5%. The Gunnison forecasts now range between 70 and 88 percent of average, with a median value of 80 percent.



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

Dolores Basin Conditions

The following conditions influenced this month's forecasts:

Precipitation:
Seasonal October through February precipitation was 105 percent of average in the Dolores basin. February precipitation was 140 percent of average.

Snow:
March 1st snow water equivalent was 105 percent of average in the Dolores basin.
--- Dolores basin snow water equivalent plot

Streamflow:
February streamflow was 60 percent of average.

Soil Moisture:
Modeled soil moisture states were below to much below average heading into the winter.

Climate Forecasts:
The correlation of El Nino and April through July water volumes in the Dolores basin is so small that it did not influence the February forecast process.

Forecast Summary:
February precipitation throughout the Dolores Basin was 140% of average. However February precipitation in the upper portions of the basin was near to below average. Therefore, the April through July volume forecast was lowered slightly by 5%. These forecasts now range between 85 and 87 percent of average, with a median value of 85 percent.



* 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: Brenda Alcorn, Tracy Cox