Since today’s weather forecasts only cover large regions every few hours, their use in severe weather is limited. In this paper, the authors present CloudCast, an application that provides short-term weather forecasts depending on user’s current location. Since severe weather is rare, CloudCast leverages pay-as-you-go cloud platforms to eliminate dedicated computing infrastructure. CloudCast has two components: an architecture linking weather radars to cloud resources, and a Nowcasting algorithm for generating accurate short-term weather forecasts. They study CloudCast’s design space, which requires significant data staging to the cloud. Their results indicate that serial transfers achieve tolerable throughput, while parallel transfers represent a bottleneck for real-time mobile Nowcasting.