New 1981-2010 Averages being used this year. 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, February 1, 2012
Upper Colorado Water Supply Outlook, February 1, 2012
The following conditions influenced this month's forecasts:
Precipitation:
Seasonal October through January precipitation
was near 75 percent of average in the Upper Colorado mainstem basin.
Above average precipitation occured in October but was followed by
two months of much below average precipitation in November and December.
January precipitation was near normal at 95 percent of average.
Snow:
February 1st snow water equivalent was near 70 percent of average in the basin as a whole.
While it is still below average, it is an improvement from the 60 percent of average
observed on January 1st.
--- Upper Colorado basin snow
water equivalent plot
Streamflow:
January streamflow was near 110 percent of average.
Soil Moisture:
Modeled soil
moisture states were above average heading into the winter.
Climate Forecasts:
La Nina climate conditions exist but these do not show a strong correlation with winter
precipitation in the Upper Colorado mainstem basin, and therefore were not influential in the development
of streamflow volume forecasts.
Forecast Summary:
Because of the below average November and, especially, December precipitation, as of February 1 both the
seasonal precipitation and snow water equivalent are below average at 75% and 70%, respectively.
However, due to a very good runoff season last year and a wet October, above average soil moisture conditions
existed in the Upper Colorado mainstem heading into the winter season. As a result of near normal January
precipitation most forecasts are unchanged from last month.
Current April through July streamflow volume forecasts
range between 70 and 86 percent of average with a median value of 80 percent.
The following conditions influenced this month's forecasts:
Precipitation:
Seasonal October through January precipitation was 85 percent of
average in the Gunnison Basin. Above average precipitation occured in October. Dry
conditions and much below average precipitation occurred in November and December.
January precipitation was near to above average in upper Gunnison
and East River Basins, with near to slightly below average precipitation elsewhere.
Snow:
February 1st snow water equivalent was 75 percent of average in the Gunnison basin.
Streamflow:
January streamflow volumes ranged from 70 to 90 percent of average.
Soil Moisture:
Modeled soil
moisture states were above average entering the winter season.
Climate Forecasts:
La Nina climate conditions exist but these do not show a strong correlation with winter
precipitation in the Gunnison Basin, and therefore were not influential in the development
of streamflow volume forecasts.
Forecast Summary:
A wet October was followed by drier condtions in November and December. January precipitation was
near or above average at most locations. Seasonal precipitation was near 85 percent of average as
of February 1st, with a basin snow water equivalent value near 75 percent of average. High runoff
in 2011 and a wet October resulted in above average soil moisture in the Gunnison Basin entering
the winter season. April-July streamflow runoff volumes changed little
from those issued January 1st and are expected to range between 60 and 80 percent of the 1981-2010
average.
The following conditions influenced this month's forecasts:
Precipitation:
Seasonal October through January precipitation was near 90 percent of average.
Precipitation was above average in October, much below average in November, and near to below average
in December.
January precipitation ranged from 80 to 95 percent of average.
Snow:
February 1st snow water equivalent was 75 percent of average in the Dolores Basin.
Streamflow:
January streamflow volumes in the Dolores River Basin were near 65 percent of average.
Soil Moisture:
Modeled soil
moisture states were near average entering the winter season.
Climate Forecasts:
La Nina climate conditions exist but does not show a strong correlation with winter
precipitation in the Dolores Basin. Therefore, it was not influential in the development
of streamflow volume forecasts.
Forecast Summary:
Near average soil moisture existed in the Dolores River Basin entering the winter
season. Seasonal precipitation was near 90 percent of average on February 1st, with October
the only month with above average precipitation. February 1st snow water equivalent
was 75 percent of average in the Dolores Basin. April-July streamflow
runoff volumes are expected to range from 65 to 80 percent of the 1981-2010 average.
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
Upper Colorado End of Month Reservoir Contents (kaf)