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.Lake Powell Water Supply Outlook, January 1, 2010
The following conditions influenced this month's forecasts:
Precipitation:
Seasonal October through December precipitation was 75 percent of average
in the Upper Green basin. December precipitation was 50 percent of average.
Snow:
January 1st snow water equivalent was near 55 percent of average in the basin
as a whole.
--- Upper Green basin snow
water equivalent plot.
Streamflow:
December streamflow was near 95 percent of average.
Soil Moisture:
Modeled soil
moisture states ranged from below average to 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 Green basin.
Forecast Summary:
Due to below average seasonal precipitation to date and much below average
January 1st snow water equivalent values the April through July streamflow
volume forecasts are below average at this time. These forecasts now range
between 65 and 78 percent of average, with a median value of 75 percent.
The following conditions influenced this month's forecasts:
Precipitation:
Seasonal October through December precipitation was 95 percent of average
in the Yampa/White basin. December precipitation was 110 percent of average.
Snow:
January 1st snow water equivalent was 80 percent of average in the basin
as a whole.
--- Yampa basin snow
water equivalent plot.
Streamflow:
December streamflow was near 90 percent of average.
Soil Moisture:
Modeled soil
moisture states were near average heading into the winter for the Little Snake
and White River basins. Modeled states ranged from below average to near average
heading into winter for the Yampa basin.
Climate Forecasts:
Climate forecasts were not a factor because there is not a strong correlation
between El Nino conditions and winter precipitation in the Yampa/White basin.
Forecast Summary:
Due to near average seasonal precipitation to date and below average
January 1st snow water equivalent values the April through July streamflow
volume forecasts are below average at this time. These forecasts now range
between 76 and 86 percent of average, with a median value of 85 percent.
The following conditions influenced this month's forecasts:
Precipitation:
Seasonal October through December precipitation was 65 percent of average
in the Duchesne basin. December precipitation was 100 percent of average.
Snow:
January 1st snow water equivalent was 70 percent of average in the basin
as a whole.
--- Duchesne basin snow
water equivalent plot.
Streamflow:
December streamflow was 105 percent of average.
Soil Moisture:
Modeled soil
moisture states were much below average to 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 Duchesne basin.
Forecast Summary:
Due to much below average seasonal precipitation to date and below average
January 1st snow water equivalent values the April through July streamflow
volume forecasts are below average at this time. These forecasts now range
between 55 and 81 percent of average, with a median value of 75 percent.
The following conditions influenced this month's forecasts:
Precipitation:
Seasonal October through December precipitation was 90 percent of average
in the Lower Green basin. December precipitation was 165 percent of average.
Snow:
January 1st snow water equivalent was 85 percent of average in the basin
as a whole.
--- Price basin snow
water equivalent plot.
Streamflow:
December streamflow was near 90 percent of average.
Soil Moisture:
Modeled soil
moisture states were much 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 Lower Green basin.
Forecast Summary:
Due to near average seasonal precipitation to date and below average
January 1st snow water equivalent values the April through July streamflow
volume forecasts are below average at this time. These forecasts now range
between 73 and 84 percent of average, with a median value of 80 percent.
The following conditions influenced this month's forecasts:
Precipitation:
Seasonal October through December precipitation was near 80 percent of average
in the Upper Colorado mainstem basin. December precipitation was near 90 percent of average.
Snow:
January 1st snow water equivalent was near 80 percent of average in the basin
as a whole.
--- Upper Colorado basin snow
water equivalent plot
Streamflow:
December 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 below average seasonal precipitation to date and below average
January 1st snow water equivalent values the April through July streamflow
volume forecasts are below average at this time. These forecasts now range
between 75 and 100 percent of average, with a median value of 85 percent.
The following conditions influenced this month's forecasts:
Precipitation:
Seasonal October through December precipitation was 80 percent of average
in the Gunnison basin. December precipitation was 100 percent of average.
Snow:
January 1st snow water equivalent was 95 percent of average in the Gunnison basin.
--- Gunnison basin snow
water equivalent plot
Streamflow:
December streamflow was 80 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:
Due to below average seasonal precipitation to date and below average
modeled soil moisture conditions, the April through July streamflow
volume forecasts are below average at this time. These forecasts now range
between 77 and 85 percent of average, with a median value of 80 percent.
The following conditions influenced this month's forecasts:
Precipitation:
Seasonal October through December precipitation was 90 percent of average
in the Dolores basin. December precipitation was 160 percent of average.
Snow:
January 1st snow water equivalent was 105 percent of average in the Dolores basin.
--- Dolores basin snow
water equivalent plot
Streamflow:
December streamflow was 70 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 January forecast process.
Forecast Summary:
Due to below average modeled soil moisture conditions, the April through July streamflow
volume forecasts are below average at this time. These forecasts now range
between 78 and 91 percent of average, with a median value of 85 percent.
The following conditions influenced this month's forecasts:
Precipitation:
Seasonal October through December precipitation amounts rose from last month to near average, 105%, due to the
wet December.
December precipitation was much above average with
155%.
Snow:
Current snow water equivalent for the entire basin is 95%, which is near average. Both the Animas and above Navajo basin
snow water equivalents were similar with 95% percent of average.
--- Animas River Basin Snow Plot.
--- Above Navajo Basin Snow Plot.
Streamflow:
Streamflow for the entire San Juan Basin was much below average in December. Seasonal streamflow since October
was also much below average due to the much below average summer through fall precipitation.
Soil Moisture:
Modeled soil
moisture as of November 1st, 2009 was below to much below average.
Climate Forecasts:
The correlation of El Nino and April through July water volumes in the San Juan basin is so small that
it did not influence the January forecast process.
Forecast Summary:
Even though seasonal precipitation and current snowpack are near average, soil moisture conditions before
the winter season were below to much below average in the upper basin. This helped drive the San Juan Water Supply
April-July forecast down to 85% of 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).