Weather modification is frequently used as an option to mitigate drought impact on surface water supplies. A dynamic climatology of cloud seeding ‘opportunities’ maybe an effective tool for either pre-drought planning or an evaluation of operational weather modification. Dynamic Climatology, with respect to this effort, is defined as the number of appropriate storm systems and/or the intra-storm duration of appropriate seeding conditions. A dynamic climatology of natural cloud seeding opportunities could be used as an alternate method to assess the potential effectiveness of weather modification programs in the water resources planning process by managers.

An effort is underway to develop a dynamic climatology of natural cloud seeding opportunities in specific watersheds in the Rocky Mountains of Colorado in the time leading up to, during and after single year and multi-year droughts. A primary goal of the study is to effectively quantify the potential impact of weather modification projects in drought mitigation from both a past case study and current evaluation mode under a variety of initial conditions and assumptions. The results of this study will be discussed at the meeting.