SLCESPAZ

NATIONAL WEATHER SERVICE
COLORADO BASIN RIVER FORECAST CENTER
SALT LAKE CITY, UTAH
Jan 16, 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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JANUARY 1-15 OBSERVED (EST.) DATA: (From USGS gage data) 
                       - values in KAF -
Jan 1-15 observed (Colorado Diamond Ck 443.7 + Muddy River 1.4 
  + Virgin River 3.7 - Powell Release 418.5) ~ 30.3 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    52  KAF (65% of average)
	   February   51  KAF (50% of average)
	   March      85  KAF (78% of average)

April - July Forecast:     163 KAF (59% of average)

January - July Forecast:   351 KAF (62% of average)

Lake Mead Evaporation Coefficients to Adjust Intervening Flow:

Jan - Mar CBRFC Evaporation amounts

	  Jan       33.9  KAF
	  Feb       31.4  KAF
	  Mar       36.3  KAF
       
Equation to use: 

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


----------------------??.?-
Tributaries:

           Virgin River
           nr Littlefield

	   Jan  9.3 KAF ( 69% of median or 49% of average)
	   Feb  8.6 KAF ( 62% of median or 53% of average)
	   Mar 11.9 KAF ( 81% of median or 51% of average)
	   
          Little Colorado
           nr Cameron

	   Jan  0.2 KAF ( 13% of median or  1% of average) 
	   Feb  1.1 KAF ( 55% of median or  6% of average) 
	   Mar  4.4 KAF ( 22% of median or 15% of average) 

          Paria Creek
           nr Lees Ferry

	   Jan  0.9 KAF ( 74% of median or  54% of average)
	   Feb  1.0 KAF ( 68% of median or  52% 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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