#LakePowell inflow forecast is 4.1 MAF (64% of average) — #Colorado Basin River Forecast Center #ColoradoRiver #COriver #aridification – Coyote Gulch

Water Supply Forecast Summary

March consisted of fairly typical spring weather across the region and featured both warm/dry periods that generated snowmelt and more active cool/wet periods that brought rain to lower elevations and snow to higher elevations. Much of the region received moisture during March, but monthly precipitation totals were generally below average. January-March has been very dry across the region, with precipitation ranking in the bottom five of the historical gage record at most SNOTEL sites across Utah, southwest Wyoming, and western Colorado during the three-month period.

Below average March precipitation across much of the region led to declines in percent of normal SWE values across most basins over the past month. April 1 snow water equivalent (SWE) conditions generally range between 75-105% of normal across the Upper Colorado River Basin and 65-85% of normal across the Great Basin. Snow across the Lower Colorado River Basin has mostly melted out with the majority of SNOTEL stations across Arizona reporting less than an inch of SWE.

Water supply forecast volumes decreased over the past month across most of the Great Basin and Colorado River Basin as a result of below normal March precipitation. Upper Colorado River Basin water supply forecasts generally range between 40-100% of the 1991-2020 historical April-July average. Great Basin water supply forecasts are 30-80% of average. Lower Colorado River Basin January-May water supply runoff volume forecasts are 10-65% of the 1991-2020 historical median.

April 1 water supply forecast ranges (percent of normal) by basin:

April-July unregulated inflow forecasts for some of the major reservoirs in the Upper Colorado River Basin include Fontenelle 435 KAF (59% average), Flaming Gorge 520 KAF (54%), Green Mountain 230 KAF (82%), Blue Mesa 530 KAF (83%), McPhee 152 KAF (60%), and Navajo 390 KAF (62%). The Lake Powell inflow forecast is 4.1 MAF (64% of average), which is a five percent decrease from March.
Warm and dry conditions are expected across the region through the start of this weekend. A shift into an active weather pattern is expected later this weekend into next week. Most of the region will see several periods of precipitation next week, with higher terrain likely to receive over an inch of precipitation.

The images below show observed snow conditions and CBRFC hydrologic model snow conditions.