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. Executive Summary (15 April 2008) "Final" version at: http://www.cdc.noaa.gov/people/klaus. wolter/SWcasts/ A moderate-to-strong La Nina has been in place since August 2007, and is expected to continue for at least another three months, possibly right through the summer. . The last four months have brought above-normal moisture to Colorado's mountains, in excess of La Nina-based expectations. In addition, colder-than- average temperatures have kept more snow on the ground into April than has been typical for quite a few years. The next two weeks do not look too promising for mOisture, but so have been many previous two-week periods tflat ended up wet in the mountains. While average seasonal temperatures are rising fast this time of year, it appears tflat we will have continued preference for colder-than-average weather in the northern mountains through the remainder of April, delaying the snowmelt further. . My experimental forecast guidance for late spring is still optimistic for eastern Colorado, while western Colorado is now more likely to be on the dry side. Once we go thru the remainder of April, the odds for a dry spring go up dramaticallydue to La Nina. A first look at the summer does not reveal a big tilt towards wet or dry conditions in Colorado, while continued La Nina conditions would favor a dry (and hot) summer. . Bottomline: The last four weeks have seen more wintery weather in the north- central mountains, while the southern mountains of Colorado have finally showing more typical La Nina-related dryness. This has eased the flooding threat in the southern part of the state, while increasing it in the northern mountains due to continued late-season build-up. After four colder-than- average months, May is the month to watch for accelerated snowmelt.