SLCESPAZ

NATIONAL WEATHER SERVICE
COLORADO BASIN RIVER FORECAST CENTER
SALT LAKE CITY, UTAH
May 1, 2018


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

Forecasts include monthly values for May - July.

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April 1-30 OBSERVED (EST.) DATA: (From USGS gage data) 
                       - values in KAF -
Apr 1-30 observed (Colorado Diamond Ck 757.5 + Muddy River 2.5 
  + Virgin River 4.4 - BOR Powell Release 704.8) ~ 59.6 KAF

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FORECASTS (using the Ensemble Prediction System):

* All Forecasts are the 50% exceedance probability value *

Lake Mead Intervening Flow:

May - July Forecasts

	   May        51  KAF (67% of average)
	   June       24  KAF (69% of average)
	   July       39  KAF (64% of average)


Lake Mead Adjusted Intervening Flow:

May - July Forecasts

	  May       27.6  KAF
	  Jun        4.6  KAF
	  Jul       40.4  KAF


Equation Used for Adjusted Flow: 

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


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Tributaries:

           Virgin River
           nr Littlefield

	   May  2.3 KAF (19% of median or  9% of average)
	   Jun  2.0 KAF (40% of median or 19% of average)
	   Jul  2.7 KAF (48% of median or 39% of average)
	   
          Little Colorado
           nr Cameron

	   May  1.0 KAF (102% of median or 24% of average) 
	   Jun  0.0 KAF (  0% of median or  0% of average) 
	   Jul  0.3 KAF ( 14% of median or  5% of average) 
 
          Paria Creek
           nr Lees Ferry

	   May  0.2 KAF ( 46% of median or 30% of average)
	   Jun  0.1 KAF ( 36% of median or 27% of average)
	   Jul  0.3 KAF ( 47% of median or 30% of average)

       * All Forecasts are the 50% exceedance probability value * 

$$

Finch/CBRFC