The following conditions influenced this month's forecasts:

Precipitation:
Seasonal October through May precipitation was below average, at 80 percent of average.

May precipitation was much below average, at 10 percent of average, in the Sevier River basin.

Streamflow:
Streamflow for the Sevier River at Hatch was 50 percent of average for May.

Snowpack:
The remaining portions of the snowpack melted out during May in the Sevier River Basin. As of June 1st, the snowpack has melted out in the overall Sevier River Basin, as well as in the headwater areas.

Sevier River Drainage Snow Plot.
Sevier River Basin Headwaters Snow Plot.
Lower Sevier River Basin Below Piute Snow Plot.

Soil Moisture:
Modeled soil moisture content was above average in the Sevier River headwater areas going into the winter.

Climate Forecasts:
Generally, climate scenarios like El Nino and La Nina do not strongly influence conditions in the Sevier River Basin. The southern part of the basin sees more of an influence from El Nino and La Nina than the northern part of the basin does. However, even in the southern part of the basin, the statistical correlations between climate indices like the Southern Oscillation Index and streamflow volumes are minor. As such, climate conditions are given only low weight, if any, in our water supply forecasts for the Sevier River basin.

Forecast Summary:
By June 1st, the snowpack melted out in the Sevier River Basin, even in the headwater areas. May precipitation was much below average, at 10 percent of average. While April streamflows were above average at most locations in the Sevier River Basin due to early snowmelt, streamflows have fallen to much below average for May due to lack of snowpack and precipitation in May. The Sevier River at Hatch monthly streamflow volume for May was 50 percent of average.

Volumes during the June-July period are expected to range from 14 to 53 percent of average. Current April through July Seasonal volume forecasts range between 28 and 70 percent of average. The median April through July forecast volume is 50 percent of average.

The forecasts for the Sevier River at Hatch, the Sevier River near Kingston, the East Fork of the Sevier River, Piute Reservoir, and the Sevier River near Gunnison are 'Regulated or Observed' flow forecasts rather than 'Natural or Unregulated' forecasts, which are corrected for all upstream diversions.

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).