Wyoming Water Supply Outlook---LAST for water year 2018--June 14, 2018

Back-to-Back Pacific Storms to Impact the West Coast; Heavy Snow in the Central Appalachians

Back-to-back powerful Pacific storm systems to impact the Pacific Northwest and northern California through the end of this week with heavy rain, flooding, strong winds, and higher elevation mountain snow. A strong, long-duration atmospheric river will accompany the Pacific storms, bringing excessive rainfall and flash flooding to southwest Oregon and northwest California through the week. Read More >

HIGHLIGHTS

…Wyoming May 2018 precipitation was 120 to 130 percent of average...

...Current water year precipitation is averaging 100 to 110 percent of normal across Wyoming…

…Mountain snowpack across Wyoming was 80 to 90 percent of median in early June...

…Overall, near normal (95 to 105 percent) snowmelt streamflow volumes are still expected across Wyoming during the rest of the snowmelt runoff season…

…Wyoming reservoir storages are at 110 to 120 percent of average for June…

SYNOPSIS

May 2018 precipitation totals across Wyoming were 120 to 130 percent of average. Precipitation numbers varied between 179 percent of normal over the Crow/Lodgepole Creek Basin (extreme southeastern Wyoming) to near 50 percent of average over the Little Snake River Basin (southern Wyoming). Current water year (October 2017 - May 2018) precipitation across Wyoming is averaging 100 to 110 percent of average.

Mountain snowpack across Wyoming was at 80 to 90 percent of median by early June. Snowpack "water" numbers and/or SWEs continue to be the highest across basins in northwest to north central Wyoming—varying between 120 to 140 percent of median. SWEs across basins in southern Wyoming were at 30 to 60 percent of median.

Overall, near normal (90 to 100 percent) snowmelt streamflow volumes are still expected across Wyoming during the rest of snowmelt runoff season. Above average (110 to 130 percent) streamflow volumes are forecasted across portions of the Wind, Shoshone, Snake, Upper Green, and Upper Yellowstone Watersheds. The Lower Green, Upper North Platte, Laramie, and Little Snake Basins are expected to have well below normal streamflow volumes the remainder of the snowmelt runoff season.

Reservoirs storages across Wyoming remained above average at 110 to 120 percent for June.

The latest Wyoming water supply outlook graphic: