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, 2009
Upper Colorado Water Supply Outlook, March 1, 2009
February precipitation was below average in the Upper Colorado Basin
and near average in the Gunnison and Dolores basins. The March 1st
snow water equivalent was above average in all of the basins, but down
just a bit from the February 1st percent of averages. Forecasts generally
held steady in the Upper Colorado Basin and dropped around 5% in the Gunnison
and Dolores basins compared to last month.
*Median of forecasts within each basin.
Upper Colorado Mainstem Basin Conditions
-Model Soil Moisture/Observed Streamflow... Soil moisture
was near to above normal in the Upper Colorado heading into the winter.
February streamflow was near normal.
-Snowpack/Precipitation... Although February precipitation was below
average in the Upper Colorado River Basin at 80%, the water year precipitation
is still slightly above average at 105%. Snow
water equivalent as of March 1st was 115% of average basin wide.
The Roaring Fork basin continues to have the highest snowpack with near
125% of average, which is a drop of about 10 percentage points from February 1st.
Most other basins had decreases closer to 5% in the snow water equivalent
percent of average from last month.
-General Discussion... Few changes were made to the April through July
streamflow volume forecasts from last month because even though there was
below average precipitation during February, the snow water equivalent
remains above average. The April through July streamflow volume forecasts
now range between 96% and 114% of average, with a median value of 110%.
-Model Soil Moisture/Observed Streamflow...Soil moisture
for most of the upper basins in the Gunnison was near to slightly below average in the fall. Observed
streamflow for the month of February was near to slightly below average for the Gunnison.
-Snowpack/Precipitation...Precipitation over the Gunnison Basin
for February was near average at 90 percent. The March 1st snow
water equivalent
percent of average was 110 percent, which dropped about 5 percent from February 1st. Seasonal precipitation for the Gunnison is 105 percent of average.
-Short Term Precipitation Forecast...The forecast models through March 10th suggest that the Gunnison Basin will see near average
precipitation with below average temperatures.
-General Discussion...The CPC guidance shows
the possibility of below average precipitation and above normal temperatures March through May.
Due to the average soil moiture in the upper basin this fall and the combination of current
snowpack conditions and the CPC forecast, the median April-July forecast for the Gunnison Basin is 105 percent of
average. This is down 5 percent from last month's forecast due to the February precipitation
and the 5 percent drop in percent of average snowpack.
-Model Soil Moisture/Observed Streamflow...Soil moisture
for most of the upper basins in the Dolores was below average in the fall. This was most likely due to
limited monsoonal precipitation during the summer months. Observed streamflow for the month of February was
mostly average for the Dolores.
-Snowpack/Precipitation...As of March 1st, snow water equivalents
across the Dolores were 115 percent of average, which was a 5 percent drop from February 1st. Precipitation over the Dolores Basin for
February was near average with 90 percent. Seasonal precipitation for the
Dolores Basin remained near average with 95 percent.
-Short Term Precipitation Forecast...The forecast models through March 10th suggest near average precipitation
with below average temperatures.
-General Discussion...The CPC guidance
shows the possibility of below average precipitation and above normal temperatures for March through May for the Dolores Basin.
Due to the below average soil moiture in the upper basin this fall and the
combination of current snowpack conditions and the CPC forecast, the median April-July forecast for the Dolores Basin
is 100 percent of average. This is down 5 percent from last month's forecast due to the February precipitation
and the 5 percent drop in percent of average snowpack.
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).