Intelligence analysts today are faced with many challenges, chief among them being the need to fuse disparate streams of data and rapidly arrive at analytical decisions and quantitative predictions for use by policy makers. A forecasting tool to anticipate key events of interest is an invaluable aid in helping analysts cut through the chatter. We present the design of user interfaces for the EMBERS system, an anticipatory intelligence system that ingests myriad open source data streams (e.g., news, blogs, tweets, economic and financial indicators, search trends) to generate forecasts of significant societal-level events such as disease outbreaks, protests, and elections. A key research issue in EMBERS is not just to generate high-quality forecasts but provide interfaces for analysts so they can understand the rationale behind these forecasts and pose why, what-if, and other exploratory questions. This thesis presents the design and implementation of three visualization interfaces for EMBERS. First, we illustrate how the rationale behind forecasts can be presented to users through the use of an audit trail and its associated visualization. The audit trail enables an analyst to drill-down from a final forecast down to the raw (and processed) data sources that contributed to the forecast. Second, we present a forensics tool called Reverse OSI that enables analysts to investigate if there was additional information either in existing or new data sources that can be used to improve forecasting. Unlike the audit trail which captures the transduction of data from raw feeds into alerts, Reverse OSI enables us to posit connections from (missed) forecasts back to raw feeds. Finally, we present an interactive machine learning approach for analysts to steer the construction of machine learning mod-els. This provides fine-grained control into tuning tradeoffs underlying EMBERS. Together, these three interfaces support a range of functionality in EMBERS, from visualization of algorithm output to a complete framework for user feedback via a tight human-algorithm loop. They are currently being utilized by a range of user groups in EMBERS: analysts, social scientists, and machine learning developers, respectively. / Master of Science