Most of Wyoming has normal water supply outlook
by Jim Fahey, Wyoming NOAA hydrologist
June 15, 2008
According to Jim Fahey, Wyoming NOAA hydrologist, the majority of the large watersheds in Wyoming have an above normal water supply. “Except for the Upper and Lower Green Basins, above normal water supply numbers continue to expected for the rest of June and into July for a majority of the large watersheds in Wyoming,” he said.
”Record and/or near record May precipitation across the state has maintained and even increased the forecasted snowmelt stream flow volumes for the next 2 months across the majority of the basins in Wyoming…Cooler than normal temperatures across Wyoming in May and into early June has maintained and/or increased the snow water equivalents (SWEs) or “water” measurements in the snowpack above 9,000 feet.”
Cooler than normal temperatures in May and early June has maintained and/or increased the already above normal SWEs or “water” measurements in the Wyoming snowpack above 9,000 feet. Snowpack "water" numbers and/or snow water equivalents (SWEs) were averaging near 149 percent of normal by early June across Wyoming. Last year--by June 11, the SWEs across the state were 16 percent of normal.
Basin-wide average precipitation in May was 110 to 210 percent of normal. For the water year 2008, many basins in Wyoming were registering 85 to 120 percent of normal precipitation. The normal to above normal precipitation numbers across the state has greatly helped increase the forecasted streamflow volumes in Wyoming.
Streamflow volumes for June and July along the Wind and Big Horn River Drainages are expected to increase to 105 to 120 percent of normal. The inflows into Boysen Reservoir are forecasted to be 105 percent of normal---with an additional 540,000 acre-feet of water expected to flow into Boysen Reservoir during the rest of June and into July.
The Upper Green and Lower Green Watershed water supply forecasts continue to point to below average snowmelt streamflow volumes---with only 70 to 85 percent of normal streamflows expected through July.
Water Supply Outlook (June 11, 2008)