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Contents
Great Basin Summary

*Median of forecasts within each basin.
Bear Basin Conditions
Many of these forecast volumes are in the top five historical observed volumes.
The following conditions influenced this month's forecasts:
Precipitation:
April
precipitation was 197 percent of average.
Seasonal, October through April
precipitation was 152 percent of average.
Streamflow:
April streamflow for the Logan River nr Logan was 115 percent of average. Woodruff Narrows inflow on the Bear River was 183 percent of average.
Snowpack:
May 1st snow water equivalent was 205 percent of the daily average. Many SNOTEL sites in the basin have snow water equivalent values in the top 5% of their
historical records, with a few at record levels.
---Upper Bear River Basin
Snow Plot.
---Bear River Below Woodruff Narrows Reservoir
Snow Plot.
---Bear River Basin
Snow Plot.
Soil Moisture:
Modeled Soil
Moisture states were near average to above average for the northern Uinta Mountains heading into the winter.
Climate Forecasts:
Climate forecasts were not factored into the northern Utah forecasts because there is not a strong statistical correlation between
El Nino/La Nina conditions and winter precipitation.
Forecast Summary:
Cooler than average temperatures during the month and much above average precipitation on top of already above average snow
accumultations have combined to create near record snow pack conditions as of May 1st.
Current
April through July seasonal volume forecasts remain much above average
and range between 156 and 245 percent of average with a median value of 221 percent.
Many of these forecast volumes are in the top five historical observed volumes.

* Percent usable capacity, not percent average contents.
Click for multi-month Graph.
Weber Basin Conditions
Many of these forecast volumes are in the top five historical observed volumes.
The following conditions influenced this month's forecasts:
Precipitation:
April
precipitation was 209 percent of average.
Seasonal October through April
precipitation was 157 percent of
average.
Streamflow:
Streamflow above Rockport Reservoir last month were 133 percent of average.
Snowpack:
May 1st snow water equivalent was 197 percent of the daily average. Many SNOTEL sites in the basin have snow water equivalent values in the top 5% of their
historical records, with a few at record levels.
---Weber River Basin
Snow Plot.
---Upper Weber River Basin
Snow Plot.
Soil Moisture:
Modeled Soil
Moisture states were mostly above normal in the western Uinta Mountains near the headwaters of the Weber heading into winter.
Climate Forecasts:
Climate forecasts were not factored into the northern Utah forecasts because there is not a strong correlation between
El Nino conditions and winter precipitation.
Forecast Summary:
Cooler than average temperatures during the month and much above average precipitation on top of already above average snow
accumultations have combined to create near record snow pack conditions as of May 1st.
Current
April through July seasonal volume
forecasts remain much above average, and range between 174 and 268 percent of average with a median value of 197 percent.
Many of these forecast volumes are in the top five historical observed volumes.

* Percent usable capacity, not percent average contents.
Click for multi-month Graph.
Six Creeks Basin Conditions
The following conditions influenced this month's forecasts:
Precipitation:
April
precipitation was 197 percent of average.
Seasonal October through April
precipitation was 159 percent
of average.
Streamflow:
Streamflows for Emigration Creek near Salt Lake City last month were 166 percent of average.
Snowpack:
May 1st snow water equivalent was 201 percent of the daily average. Many SNOTEL sites in the basin have snow water equivalent values in the top 5% of their
historical records, with a few at record levels.
---Six Creeks River Basin
Snow Plot.
---Big and Little Cottonwood Canyons
Snow Plot.
Soil Moisture:
Modeled Soil
Moisture states were near average in the Six Creeks Basin heading into winter.
Climate Forecasts:
Climate forecasts were not factored into the northern Utah forecasts because there is not a strong correlation between
El Nino conditions and winter precipitation.
Forecast Summary:
Cooler than average temperatures during the month and much above average precipitation on top of already above average snow
accumultations have combined to create near record snow pack conditions as of May 1st.
Current
April through July seasonal volume forecasts are much above average,
and range between 150 and 231 percent of average with a median value of 177 percent of average.
Many of these forecast volumes are in the top five historical observed volumes.

* Percent usable capacity, not percent average contents.
Click for multi-month Graph.
Utah Lake Basin Conditions
Many of these forecast volumes are in the top five historical observed volumes.
The following conditions influenced this month's forecasts:
Precipitation:
April
precipitation was 196 percent of average.
Seasonal October through April
precipitation is 159 percent of average.
Streamflow:
Streamflow for the Provo at Woodland last month was 93 percent of average. Unregulated inflows to Utah Lake
were 131 percent of average.
Snowpack:
May 1st snow water equivalent was 212 percent of the daily average. Many SNOTEL sites in the basin have snow water equivalent values in the top 5% of their
historical records, with a few at record levels.
---Provo River, Utah Lake Basin
Snow Plot.
Soil Moisture:
Modeled Soil
Moisture states were average to above average heading into the winter.
Climate Forecasts:
Climate forecasts were not factored into the northern Utah forecasts because there is not a strong correlation between
El Nino conditions and winter precipitation here.
Forecast Summary:
Cooler than average temperatures during the month and much above average precipitation on top of already above average snow
accumultations have combined to create near record snow pack conditions as of May 1st.
April through July seasonal volume forecasts remain much above average
and range between 174 and 213 percent of average with a median value of 205 percent.
Many of these forecast volumes are in the top five historical observed volumes.

* 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).
Monthly Streamflows




Precipitation Maps


Hydrologist: B.Bernard