SLCESPAZ

NATIONAL WEATHER SERVICE
COLORADO BASIN RIVER FORECAST CENTER
SALT LAKE CITY, UTAH
April 16, 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 1-15 OBSERVED (EST.) DATA: (From USGS gage data) 
                       - values in KAF -

(Colorado Diamond Ck 950.1 + Muddy River 2.8 + 
Virgin River 42.0 - BOR Powell Release 797.6) ~ 197.3 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      97  KAF (101% of average)
          May        83  KAF ( 89% of average)
          June       62  KAF (100% of average)


Lake Mead Adjusted Intervening Flow:

April - June Forecasts

	  April      68.0  KAF
          May        56.6  KAF
          June       42.8  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  29.8 KAF (208% of median or 138% of average)
           May  26.3 KAF (234% of median or 109% of average)
           June 10.2 KAF (221% of median or 100% of average)
	   
          Little Colorado
           nr Cameron

	   Apr  5.2 KAF ( 112% of median or  30% of average)
           May  2.3 KAF (1825% of median or  64% of average)
           June 0.2 KAF (1000% of median or 111% of average)
        
          Paria Creek
           nr Lees Ferry

	   Apr  4.0 KAF (456% of median or 358% of average)
           May  1.6 KAF (354% of median or 244% of average)
           June 0.4 KAF (141% of median or  90% of average)

       * All Forecasts are the 50% exceedance probability value * 

$$

Finch/CBRFC