SLCESPAZ

NATIONAL WEATHER SERVICE
COLORADO BASIN RIVER FORECAST CENTER
SALT LAKE CITY, UTAH
Dec 4, 2017


The following are updated forecasts for the Lake Mead Local 
(or intervening flow).

Forecasts include monthly values for Dec - Feb.
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Nov OBSERVED Volumes (est.): (From USGS gage data) 
                       - values in KAF -
Nov observed (Colorado Diamond Ck 682.5 Muddy River 2.4 
  + Virgin River 12.8 - Powell Release 628.9) ~ 68.8 KAF  

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FORECASTS (using the Ensemble Prediction System):

* All Forecasts are the 50% exceedance probability value *

Lake Mead Intervening Flow:

Dec - Feb Forecasts

	   Dec        46  KAF ( 75% of average)
	   Jan        55  KAF ( 69% of average)
	   Feb        56  KAF ( 55% of average)
       
Lake Mead Evaporation Coefficients to Adjust Intervening Flow:

Nov - Jan CBRFC Evaporation amounts

	  Dec       40.2  KAF
	  Jan       33.8  KAF
	  Feb       31.3  KAF
       
Equation to use: 

Inflow(BOR) = Inflow(NWS) + Evap(BOR) - Evap(NWS) + Bankstorage(BOR)

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Tributaries:

           Virgin River
           nr Littlefield

	   Dec 8.7 KAF ( 72% of median or  64% of average)
	   Jan 9.6 KAF ( 71% of median or  50% of average)
	   Feb 8.2 KAF ( 59% of median or  50% of average)
	   
          Little Colorado
           nr Cameron

	   Dec  0.5 KAF ( 79% of median or  11% of average) 
	   Jan  2.0 KAF (128% of median or  12% of average) 
	   Feb  4.5 KAF (224% of median or  26% of average) 

          Paria Creek
           nr Lees Ferry

	   Dec  0.7 KAF ( 60% of median or  56% of average)
	   Jan  0.9 KAF ( 74% of median or  54% of average)
	   Feb  1.7 KAF (116% of median or  88% of average)

       * All Forecasts are the 50% exceedance probability value * 

CBRFC

NNNN

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