FGUS65 KSTR 061756
ESGNM 
TTAA00 KSLR DDHHMM
NATIONAL WEATHER SERVICE
COLORADO BASIN RIVER FORECAST CENTER
SALT LAKE CITY UT
May 6, 2004

           INTERNAL NWS PRODUCT FOR GUIDANCE PURPOSES ONLY

 SAN JUAN RIVER BASIN SPRING FLOOD POTENTIAL OUTLOOK

The 2004 spring runoff forecasts and flood potential is average for 
streams throughout the San Juan River Basin. 

Following an extraordinarily warm March and large snow losses, April was very
wet. April precipitation was very high marking at nearly 190% of average for
the basin. Snowpack ended the month at 92% of average and flow for the second
straight month was above average at 104%. Despite these high marks the
fact remains that most low and mid elevation snow is gone. A rain on snow 
event during May and June could produce significant runoff despite the lack of 
mid and low elevation snow. However in general most forecasts are below what
might be expected given the rain and snow we've had to date. Most April - 
July snowmelt runoff volume forecasts were raise slightly from April 1 
numbers and range from 38% in SE Utah to 91% at Lemon Reservoir. The median
of 16 forecast was 78% of average. 

The current short term CPC climate forecast (6-14 days) indicates a slightly 
above average shift in temperature and a below average probability of 
precipitation for SW Colorado. The May climate forecast calls for the same, 
above average temperatures and below average precip. Finally the MJJ seasonal
climate forecast calls for above average temperature and EC (Equal Chances) 
of a distribution shift to above, average or below average precipitation 
potential. Temperatures are currently warming and we will see rivers peaking 
during the next 4 weeks, based on these forecasts.


CBRFC/BMB


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