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The Colorado Basin River Forecast Center (CBRFC) geographic forecast area includes the Upper Colorado River Basin, Lower Colorado River Basin, and Eastern Great Basin.
Water Supply Forecast Summary
Early June water supply volume forecasts are below to much below normal throughout the Colorado River Basin and Great Basin. Upper Colorado River Basin water supply forecasts range between 15-80% of the 1981-2010 historical April-July average. Great Basin water supply forecasts are 5-50% of average. Many April-July volume forecasts fall in the bottom (driest) five on record.
The trend in water supply volume guidance over the past month generally followed the trend in May observed precipitation. Near normal May precipitation across the Upper Green, Upper Colorado mainstem, and San Juan Basins led to relatively minor changes in water supply guidance over the past month while below normal May precipitation across the White/Yampa and Great Basins resulted in decreases in water supply guidance compared to a month ago. June water supply forecast ranges (percent of April-July normal volume) by basin are listed below.
Below normal soil moisture and snowpack conditions in addition to mostly below average spring precipitation and relatively mild (near normal) spring temperatures across the Upper Colorado River Basin and Great Basin have resulted in much below normal and in some cases record low observed April-May flows (unregulated streamflow volumes) across the region. A number of streamflow sites across Utah reported the lowest April-May observed flow on record, with most locations falling in the bottom three. Many streamflow sites across western Colorado have reported April-May observed flows in the bottom five on record.
Snow water equivalent (SWE) at the majority of SNOTEL stations across the region peaked between 70-85% of the normal peak SWE this season. Early June SWE conditions are below to much below normal at most SNOTEL stations across the Colorado River Basin and Great Basin. Basins with the best remaining snowpack are the Upper Green headwaters and Upper Colorado headwaters, where a handful of high elevation SNOTEL stations are reporting 5-10 inches of SWE (50-85% of normal). Little to no snow is being reported at SNOTEL stations across Utah/Great Basin and southwest Colorado (Gunnison, Dolores, San Juan Basins).
April-July unregulated inflow forecasts for some of the major reservoirs in the Upper Colorado River Basin include Fontenelle 345 KAF (48% of average), Flaming Gorge 395 KAF (40%), Green Mountain 150 KAF (55%), Blue Mesa 310 KAF (46%), McPhee 76 KAF (26%), and Navajo 335 KAF (46%). The Lake Powell inflow forecast is 1.8 MAF (25% of average), a three percent decrease from May.