SLCESPAZ

NATIONAL WEATHER SERVICE
COLORADO BASIN RIVER FORECAST CENTER
SALT LAKE CITY, UTAH
April 15, 2019


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

Forecasts include monthly values for April - June.

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April 1-14 OBSERVED (EST.) DATA: (From USGS gage data) 
                       - values in KAF -

(Colorado Diamond Ck 383.8 + Muddy River 1.2 + 
Virgin River 10.6 - BOR Powell Release 337.0) ~ 58.6 KAF

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FORECASTS (using the Ensemble Prediction System):

* All Forecasts are the 50% exceedance probability value *

Lake Mead Intervening Flow:

April - June Forecasts

	  April      99  KAF (103% of average)
          May        87  KAF ( 94% of average)
          June       62  KAF (100% of average)


Lake Mead Adjusted Intervening Flow:

April - June Forecasts

	  April      85.6  KAF
          May        62.1  KAF
          June       42.0  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

	   Apr  30.0 KAF (209% of median or 139% of average)
           May  30.5 KAF (271% of median or 126% of average)
           Jun  10.2 KAF (221% of median or 100% of average)
	   
          Little Colorado
           nr Cameron

	   Apr  11.6 KAF ( 112% of median or  30% of average)
           May   2.2 KAF (1746% of median or  61% of average)
           Jun   0.2 KAF (1000% of median or 111% of average)
        
          Paria Creek
           nr Lees Ferry

	   Apr  1.9 KAF (216% of median or 170% of average)
           May  1.2 KAF (266% of median or 183% of average)
           Jun  0.4 KAF (141% of median or  90% of average)

       * All Forecasts are the 50% exceedance probability value * 

$$

Finch/CBRFC