The following conditions influenced this month's forecasts:

Precipitation:
Seasonal October through March precipitation was 87 percent of average in the upper Bear Basin. March precipitation was 55 percent of average.

Streamflow:
The Bear River at Stewart Dam was 121 percent of average. The Logan River above State Dam was estimated at 129 percent of average streamflow.

Snowpack:
This years snow pack is much below average for April 1st. The current snow water equivalent for the Bear Basin is 59 percent of average. As of water year 2012 the CBRFC has re-calculated all snow stations to reflect the new 30 year average from 1981-2010.


Upper Bear River Basin Snow Plot.
Bear River Below Woodruff Narrows Reservoir Snow Plot.
Bear River Basin Snow Plot.

Soil Moisture:
Modeled Soil Moisture, click on map to zoom. Modeled soil moisture states indicate above average moisture conditions as of March 1st. This is a contributor to the above average baseflows in the Bear River Basin.

Climate Forecasts:
Climate forecasts were not a factored into the northern Utah forecasts because there is not a strong correlation between La Nina conditions and winter precipitation.

Forecast Summary:
A wet October was then followed by dry November and December. January and February precipitation was near normal and then the things changed with a very dry and warm March. Seasonal precipitation throughout the GSL Basin as of April 1st ranges between 73 and 97 percent of average but snowpacks have suffered greatly in March and range from 49 to 57 percent of average. Streamflow forecast have been significantly reduced from March 1st numbers due to the amount of snow that melted. April through July seasonal volume forecast range from 38 to 67 percent of average with a median volume of 55 percent of average.

The following conditions influenced this month's forecasts:

Precipitation:
Seasonal October through March precipitation is 73 percent of average. March precipitation was 58 percent of average.

Streamflow:
The Weber at Oakley gage was estimated to be 112 percent of average. The inflow to Rockport Reservoir was 97 percent of average.

Snowpack:
This years snow remains below average. The current snow water equivalent index is 52 percent of average.. As of water year 2012 the CBRFC has re-calculated all snow stations to reflect the new 30 year average from 1981-2010.

Weber River Basin Snow Plot.
Upper Weber River Basin Snow Plot.

Soil Moisture:
Modeled Soil Moisture, click on map to zoom. Modeled soil moisture states indicate above average moisture conditions as of December 1st. This is a contributor to the above average baseflows in the Weber River Basin.

Climate Forecasts:
Climate forecasts were not a factored into the northern Utah forecasts because there is not a strong correlation between La Nina conditions and winter precipitation.

Forecast Summary:
A wet October was then followed by dry November and December. January and February precipitation was near normal and then the things changed with a very dry and warm March. Seasonal precipitation throughout the GSL Basin as of April 1st ranges between 73 and 97 percent of average but snowpacks have suffered greatly in March and range from 49 to 57 percent of average. Streamflow forecast have been significantly reduced from March 1st numbers due to the amount of snow that melted. April through July seasonal volume forecasts range between 42 and 55 percent of average with a median forecast volume of 48 percent of average.

The following conditions influenced this month's forecasts:

Precipitation:
Seasonal October through March precipitation was near 74 percent of average. March precipitation was 67 percent of average.

Streamflow:
March streamflow for City Creek near Salt Lake City was 66 percent of average. Big Cottonwood Creek nr Salt Lake City was 91 percent of average.

Snowpack:
This year's snow remains below average. The current indexed snow water equivalent is 59 percent of average. As of water year 2012 the CBRFC has re-calculated all snow stations to reflect the new 30 year average from 1981-2010.

Six Creeks Headwaters Basins Snow Plot.

Big and Little Cottonwood Canyons Snow Plot.

Soil Moisture:
Modeled Soil Moisture, click on map to zoom. Modeled soil moisture states indicate mostly above average mositure conditions as of December 1st. Although flows are dropping in the Six Creeks basin, above average soil moistures have been influencing baseflows through the fall and March was the first month that they dropped to near average.

Climate Forecasts:
Climate forecasts were not factored into the northern Utah forecasts because there is not a strong correlation between La Nina conditions and winter precipitation.

Forecast Summary:
A wet October was then followed by dry November and December. January and February precipitation was near normal and then the things changed with a very dry and warm March. Seasonal precipitation throughout the GSL Basin as of April 1st ranges between 73 and 97 percent of average but snowpacks have suffered greatly in March and range from 49 to 57 percent of average. Streamflow forecast have been significantly reduced from March 1st numbers due to the amount of snow that melted. April through July seasonal volume forecasts range between 42 to 66 percent of average with a median forecast of 48 percent of average.

The following conditions influenced this month's forecasts:

Precipitation:
Seasonal October thought March seasonal precipitation was 76 percent of average. March precipitation was 66 percent of average.

Streamflow:
Streamflows for the Provo at Woodland were 99 percent of average. Unregulated inflow to Utah Lake was recorded at 76 percent of average which represents a significant drop from the previous month.

Snowpack:
This year's snow as of March 1 remains below average. Current snow water equivalent are 67 percent of average.. As of water year 2012 the CBRFC has re-calculated all snow stations to reflect the new 30 year average from 1981-2010.

Provo River, Utah Lake Drainage Snow Plot.

Soil Moisture:
Modeled Soil Moisture, click on map to zoom. Modeled soil moisture states indicate mostly average to above average conditions as of December 1st. This is a contributor to the current baseflows conditions in the Provo and Utah Lake forecast.

Climate Forecasts:
Climate forecasts were not factored into the northern Utah forecasts because there is not a strong correlation between La Nina conditions and winter precipitation here.

Forecast Summary:
A wet October was then followed by dry November and December. January and February precipitation was near normal and then the things changed with a very dry and warm March. Seasonal precipitation throughout the GSL Basin as of April 1st ranges between 73 and 97 percent of average but snowpacks have suffered greatly in March and range from 49 to 57 percent of average. Streamflow forecast have been significantly reduced from March 1st numbers due to the amount of snow that melted. April through July seasonal volume forecasts range between 26 and 60 percent of average with a median forecast volume of 53 percent 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).

10% exceedance forecast: Given the current hydrometeorological conditions, i.e current snowpack, soil moisture and streamflow, the volume that has a 10% chance of being exceeded. Previously referred to as "Reasonable Maximum Forecast".

50% exceedance forecast: Given the current hydrometeorological conditions, i.e current snowpack, soil moisture and streamflow, the volume that has a 50% chance of being exceeded. Previously referred to as "Most Probable Forecast".

90% exceedance forecast: Given the current hydrometeorological conditions, i.e current snowpack, soil moisture and streamflow, the volume that has a 90% chance of being exceeded. Previously referred to as "Reasonable Minimum Forecast".

Acre-Foot (af): The volume equal to one acre covered one foot deep (43,560 cubic feet). See kaf below.

Average: The arithmetic mean. The sum of the values divided by the number of values. Values from 1981-2010 are used for this publication.

Categories: Much Above Average=Greater than 130%, Above Average=111-130%, Near Average=90-110%, Below Average=70-89%, Much Below Average=Less than 70%.

CBRFC: Colorado Basin River Forecast Center.

Forecast Period: The period from April 1 through July 31, unless otherwise noted.

kaf: Thousand Acre-Feet. See Acre-Foot above.

Inflow: The volume of water that flows into a reservoir or lake.

Median: The middle value of an ordered set of values. Half of the values are higher and half of the values are lower. When the set contains an even number of values the median is the average of the two middle numbers.

NOAA: National Oceanic and Atomospheric Administration.

NWS: National Weather Service.

Water supply forecasts take into consideration present hydrometeorological conditions and use average basin temperatures and precipitation for the forecast period. As the forecast season progresses, a greater portion of the future hydrologic and climatic uncertainty becomes known and monthly forecasts become more accurate. For more information on the tools we use, consult Water Supply Forecasting Tools.

Volume forecasts represent adjusted flows; that is, observed flows with upstream water use taken into account. Adjusted flows will closely approximate natural or unimpaired flows. However, not all upstream diversions or impoundments are measured or quantifiable. For specific adjustments used with each forecast point, consult the Guide to Water Supply Forecasting.

The Water Supply Outlook is issued monthly January through May by the Colorado Basin River Forecast Center. It represents a coordinated effort between the National Weather Service, Natural Resources Conservation Service, Bureau of Reclamation, U.S. Geological Survey and local water district managers.

Note: Data used in this report are provisional and are subject to revision.

For more information, or to be included on the mailing list, please contact:

Colorado Basin River Forecast Center
2242 W North Temple
Salt Lake City, UT 84116
(801) 524-5130
www.cbrfc.noaa.gov