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- 6- · San J uanmolores - is the southwest comer of state and in near drought conditions. It was good year last year but they have water shortages to deal with since 2000. In this basin the reservoirs are the bright spot. They have carryover storage that will help a lot. . The DWR has not out hvdro!!raohs to!!ether vet as it's not (llIit" nm off <,,"<on An "r,," of . . ..... ..... '" . _ _.._ _ __ _ _u_ ___. _ ___ n_ _.. _ concern is Dillon Reservoir that has only 25,000 AF of excess capacity right now. There are concerns for Silverthorne. Denver Water will look at April I snowpack numbers and possibly evacuate storage space. National Weather Service short term weather forecast (Treste Huse) · Treste Huse, the Service hydrologist in the Boulder National Weather Service office, gave this update. She showed the current flood risk map. This year we are looking at below normal flood risk for the peak run off flows generally statewide. · For the Roaring Fork River there is a greater than normal risk of flooding this year. Tom Browning at the CWC8 reminded us that even though the snowmelt flood threat is lower this year, the 1976 big Thompson flood was a rain flash flood and so were the 1997 Spring Creek flood in Fort Collins, and the 1999 Arkansas River Flooding. 1984 was last snowmelt flooding event. . A ridge is building Thursday through Saturday. Saturday night a system moving in, but if it moves to four corners low we can see some moisture. Southeasterly flow can bring the best moisture and can bring in potential for four comers low and potential for precipitation. NOAA Climate Dia2nostics Center (Klaus Wolter) - You can find Klaus Wolter's forecasts at http://www.cdc.noaa.gov/people/k1aus.wolter/SWcasts. Recently we have had La Nina and EI Nino situations. · Officially NOAA calls this year a La Nina but it's just at the threshold for being called a La Nina year. The significant impact of weak La Nina year to Colorado's climate is that it doesn't make significant differences above what is average. Klaus's summer forecast is ready March 17th. . Klaus verified last summer and last winter's forecasts by comparisons to actual precipitation from July-September 2005. His forecast skill is better in the winter months. EI Nino Southern Oscillation ENSO forecasts from 12 numerical and 8 statistical forecast models: in September, not a single model predicted La Nina conditions of the strength currently observed; the preliminary update for this month shows almost all models reverting back to "normal" by this summer. . An interesting trend this year was the cold temperatures in Alaska. Since the mid 1970s it hadn't been that cold in Alaska. When you build cold air in Alaska it needs to go somewhere and it tends to be cold along the spine of the Colorado Rocky Mountains. The cold air when through Siberia and then back to us this year. . The European forecast model shows things might warm up. So far this is the model of choice. It is tough for certainties with La Nina years as there aren't the documented cases. It started late and it hasn't run its course yet. From 20 different model runs, only 2 of the 20 show an intensification of La Nina. . Last month's Climate Prediction Center forecasts for the next six months are undecided ('EC') for us, although an increased tilt towards dryness to our south is consistent with albeit weak La Nina conditions. When you use weak La Nina years the biggest difference is in southeast. It tends to be wet on southeastern plains and dry along foothills. . The constructed analogs find similarities and differences by the historical precedent. The spring season is when this tool works the best. It has this huge bull's eye of dry in Colorado this spring. Flood Protection. Water Project Planning and Finance. Stream and Lake Protection Water Supply Protection. Conservation PlaMing