SLCESPAZ

NATIONAL WEATHER SERVICE
COLORADO BASIN RIVER FORECAST CENTER
SALT LAKE CITY, UTAH
December 17, 2018


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

Forecasts include monthly values for December - February.

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December 1-16 OBSERVED (EST.) DATA: (From USGS gage data) 
                       - values in KAF -

(Colorado Diamond Ck 394.5 + Muddy River 1.3 + 
Virgin River 4.6 - BOR Powell Release 361.0) ~ 39.4 KAF

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FORECASTS (using the Ensemble Prediction System):

* All Forecasts are the 50% exceedance probability value *

Lake Mead Intervening Flow:

December - February Forecasts

	   December   60  KAF (73% of average)
	   January    60  KAF (59% of average)
           February   61  KAF (63% of average)


Lake Mead Adjusted Intervening Flow:

December - February Forecasts

	  December   72.0  KAF
	  January    77.4  KAF
          February   62.9  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

	   Dec  7.9 KAF (65% of median or 48% of average)
	   Jan  8.5 KAF (67% of median or 47% of average)
           Feb  7.2 KAF (59% of median or 47% of average)
	   
          Little Colorado
           nr Cameron

	   Dec  0.1 KAF ( 17% of median or  2% of average)
	   Jan  1.0 KAF ( 97% of median or  7% of average)
           Feb  3.7 KAF (283% of median or 24% of average)
        
          Paria Creek
           nr Lees Ferry

	   Dec  1.0 KAF ( 86% of median or 75% of average)
	   Jan  1.2 KAF ( 98% of median or 75% of average)
           Feb  1.6 KAF (119% of median or 88% of average)

       * All Forecasts are the 50% exceedance probability value * 

$$

Finch/CBRFC