FGUS65 KSTR 071918 ESGNM TTAA00 KSLR DDHHMM NATIONAL WEATHER SERVICE COLORADO BASIN RIVER FORECAST CENTER SALT LAKE CITY UT MAY 7,2003 INTERNAL NWS PRODUCT FOR GUIDANCE PURPOSES ONLY SAN JUAN RIVER BASIN SPRING FLOOD POTENTIAL OUTLOOK As of May 1, 2003 the spring snowmelt runoff forecasts and flood potential outlooks are low for streams throughout the San Juan River Basin. Observed April precipitation was 31% of average. The May 1, snowpack was 52% of Average. The spring runoff forecasts call for much below average volumes (20%-57%). The median forecast from a sample population of 15 was 45% of average. Observed March streamflow was 50% of average. This low number despite the fact that melt occurred during the last 10 days of April. Snowpack decreased in April by 16% of average or 22% of this year total snow pack. Seasonal precipitation is now at 81% of average. Despite the reasonable seasonal numbers the basin is again headed for a much below normal water year with low potential for flooding if current conditions persist. It is important to note that runoff, to a large extent, will be determined by hydrometeorologic events occurring during May and June. Max Mean Daily Peak Flow Forecast Forecast Flood Flow Hist. Avg. 2001 Peak Per.of Peak San Juan -Pagosa Spgs. 920 cfs 11712 cfs 2485 cfs 221 cfs 5/15-6/12 Animas -Durango 2450 cfs 9664 cfs 4675 cfs 777 cfs 5/28-6/14 San Juan -Bluff 2950 cfs 41052 cfs 7340 cfs 847 cfs 5/21-7/4 CBRFC/BMB NNNN $$