SLCESPAZ NATIONAL WEATHER SERVICE COLORADO BASIN RIVER FORECAST CENTER SALT LAKE CITY, UTAH August 15, 2018 The following are updated forecasts for the Lake Mead Local (or intervening flow). Forecasts include monthly values for August - October. ------------------------------------------------------------------- August 1-14 OBSERVED (EST.) DATA: (From USGS gage data) - values in KAF - (Colorado Diamond Ck 468.3 + Muddy River 1.0 + Virgin River 1.3 - BOR Powell Release 400.0) ~ 70.6 KAF ------------------------------------------------------------------- FORECASTS (using the Ensemble Prediction System): * All Forecasts are the 50% exceedance probability value * Lake Mead Intervening Flow: August - October Forecasts August 65 KAF (71% of average) September 60 KAF (79% of average) October 53 KAF (74% of average) Lake Mead Adjusted Intervening Flow: August - October Forecasts August 80.1 KAF September 56.1 KAF October 36.8 KAF Equation Used for Adjusted Flow: Inflow(BOR) = Inflow(NWS) + Evap(BOR) - Evap(NWS) + BankStorageChange(BOR) ------------------------------------------------------------------- Tributaries: Virgin River nr Littlefield Aug 6.0 KAF (78% of median or 67% of average) Sep 5.0 KAF (75% of median or 56% of average) Oct 7.2 KAF (66% of median or 64% of average) Little Colorado nr Cameron Aug 5.0 KAF (49% of median or 25% of average) Sep 8.6 KAF (78% of median or 62% of average) Oct 1.2 KAF (83% of median or 17% of average) Paria Creek nr Lees Ferry Aug 1.5 KAF (81% of median or 66% of average) Sep 1.0 KAF (75% of median or 54% of average) Oct 0.9 KAF (61% of median or 46% of average) * All Forecasts are the 50% exceedance probability value * $$ Finch/CBRFC