SLCESPAZ

NATIONAL WEATHER SERVICE
COLORADO BASIN RIVER FORECAST CENTER
SALT LAKE CITY, UTAH
Mar 14, 2018


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

Forecasts include monthly values for March - May and seasonal 
volumes for Mar - July and Apr - July.

-------------------------------------------------------------------
March 1-13 OBSERVED (EST.) DATA: (From USGS gage data) 
                       - values in KAF -
Mar 1-13 observed (Colorado Diamond Ck 355.2 + Muddy River 1.2 
  + Virgin River 3.9 - Powell Release 345.3) ~ 15.0 KAF

-------------------------------------------------------------------
FORECASTS (using the Ensemble Prediction System):

* All Forecasts are the 50% exceedance probability value *

Lake Mead Intervening Flow:

March - May Forecasts

	   March      51  KAF (47% of average)
	   April      50  KAF (48% of average)
	   May        51  KAF (67% of average)

April - July Forecast:     172 KAF (62% of average)

March - July Forecast:     223 KAF (58% of average)

Lake Mead Evaporation Coefficients to Adjust Intervening Flow:

Mar - May CBRFC Evaporation amounts

	  Mar       36.5  KAF
	  Apr       37.8  KAF
	  May       47.1  KAF
       
Equation to use: 

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


-------------------------------------------------------------------
Tributaries:

           Virgin River
           nr Littlefield

	   Mar  6.4 KAF (43% of median or 27% of average)
	   Apr  5.4 KAF (36% of median or 24% of average)
	   May  3.7 KAF (31% of median or 15% of average)
	   
          Little Colorado
           nr Cameron

	   Mar  0.4 KAF (  2% of median or  1% of average) 
	   Apr  1.3 KAF ( 17% of median or  7% of average) 
	   May  2.1 KAF (215% of median or 50% of average) 
 
          Paria Creek
           nr Lees Ferry

	   Mar  0.7 KAF (43% of median or 31% of average)
	   Apr  0.6 KAF (60% of median or 52% of average)
	   May  0.2 KAF (46% of median or 30% of average)

       * All Forecasts are the 50% exceedance probability value * 


NNNN

$$