Here’s the update from the Colorado Water Conservation Board and the Colorado Division of Water Resources (Taryn Finnessey/Tracy Kosloff):
Following cooler than average temperatures in August across much of the state, September has been hot and dry. Consequently, both abnormally dry and moderate drought conditions have expanded across western Colorado. Reservoir storage is well above average, and municipal water providers have no immediate concerns with levels of supply and demand in their systems.
After receiving only 69 percent of statewide average precipitation in August at SNOTEL stations, September precipitation to date remains low at 30 percent of average as of September 14. The South Platte was the only basin to receive normal precipitation levels in August (100 percent); while the Arkansas is the only basin to receive above normal precipitation (122 percent) September to date. All other basins are experiencing well below average precipitation for the month, ranging from zero (Yampa/ White) to 44 percent (Upper Colorado). Reservoir storage statewide is at 120 percent of normal, with all basins above average. The Rio Grande basin is reporting above average storage (133 percent) for the first time since 2009. The Colorado and Yampa/ White basins have the lowest storage levels in the state at 110 percent of normal. 31 percent of Colorado is classified as abnormally dry (D0), while 4 percent is classified as experiencing moderate drought, predominantly concentrated in Rio Blanco and Garfield Counties. Warmer than normal temperatures have affected Colorado over the last few weeks, with western slope temperatures averaging as much as eight degrees above normal.
ENSO-neutral conditions remain, but a La Nina watch has been issued by NOAA with more than 50 percent likelihood of a La Nina developing. Short term forecasts show that temperatures should cool off, with parts of the west receiving significant precipitation. This is a welcome change for those areas currently battling forest fires. Long term forecast shows no major indication towards wet or dry in the upcoming months. If La Niña conditions set in, mountain snows are often enhanced during the winter season, but fall and spring tend to be dry.