Conventional wisdom often views the urban water sector as being among the more sensitive sectors in the arid U.S. Southwest. To test this assumption, the Climate Assessment Project for the Southwest analyzed the water budgets of five Arizona cities to determine how severe the impacts would be from the deepest one-, five-, and ten-year droughts on record. Case study sites for the analysis included the Phoenix Active Management Area, Tucson Active Management Area, Santa Cruz Active Management Area, and the Benson and Sierra Vista subwatersheds of the San Pedro River.

In support of the Climate Assessment Project for the Southwest, a review was conducted of the current state of weather, climate, and hydrologic forecasting for the Southwest. A key element of the review was a workshop that examined the availability, use, accuracy, and value of forecasts, with participants consisting primarily of agency personnel involved in operational forecasting via directly issuing forecasts, providing key data for making forecasts, or serving as a key link for communicating forecasts. The broad range of forecast products encompasses myriad variables, time-scales from minutes to seasons, and lead-times from minutes to over a year. Current forecast products and techniques are reviewed, and implications for use in decision making are discussed. The forecast review identified needs for additional research to be addressed by the CLIMAS Project, including local evaluation of monthly and seasonal climate outlooks, retrospective evaluation of operational water supply outlooks, hindcast reanalysis of probabilistic water supply outlook techniques, and incorporation of climate outlooks into statistical water supply outlook techniques.