SLCESPAZ

NATIONAL WEATHER SERVICE
COLORADO BASIN RIVER FORECAST CENTER
SALT LAKE CITY, UTAH
Jan 2, 2018


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

Forecasts include monthly values for January - March and seasonal 
volumes for Jan - July and Apr - July.

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DECEMBER OBSERVED (EST.) DATA: (From USGS gage data)

                       - values in KAF -
Dec observed (est.) (Colorado Diamond Ck 802.1 + Muddy River 2.5 
  + Virgin River 6.3 - Powell Release 744.2) ~ 66.7 KAF
   
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FORECASTS (using the Ensemble Prediction System):

* All Forecasts are the 50% exceedance probability value *

Lake Mead Intervening Flow:

January - March Forecasts

	   January    51  KAF ( 64% of average)
	   February   51  KAF ( 50% of average)
	   March      83  KAF ( 76% of average)

April - July Forecast:     144 KAF ( 52% of average)

January - July Forecast:   330 KAF ( 58% of average)

Lake Mead Evaporation Coefficients to Adjust Intervening Flow:

Jan - Mar CBRFC Evaporation amounts

	  Jan       34.0  KAF
	  Feb       31.4  KAF
	  Mar       36.3  KAF
       
Equation to use: 

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


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Tributaries:

           Virgin River
           nr Littlefield

	   Jan  8.0 KAF ( 59% of median or 42% of average)
	   Feb  6.2 KAF ( 45% of median or 38% of average)
	   Mar  9.4 KAF ( 64% of median or 40% of average)
	   
          Little Colorado
           nr Cameron

	   Jan  0.3 KAF ( 19% of median or  2% of average) 
	   Feb  3.1 KAF (154% of median or 18% of average) 
	   Mar  5.2 KAF ( 25% of median or 17% of average) 

          Paria Creek
           nr Lees Ferry

	   Jan  0.6 KAF ( 50% of median or  36% of average)
	   Feb  1.4 KAF ( 95% of median or  72% of average)
	   Mar  1.5 KAF ( 92% of median or  67% of average)

       * All Forecasts are the 50% exceedance probability value * 

CBRFC

NNNN

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