Rain, ice, hail, severe winds, thunderstorms, and heavy fog – the Appalachian Mountains in the southeast United States have it all. On May 1, NASA begins a campaign in western North Carolina to better understand the difficult-to-predict weather patterns of mountain regions. The field campaign serves as ground truth for measurements made by the Global Precipitation Measurement (GPM) mission's Core Observatory. GPM is an international satellite mission to observe rain and snow around the world. The advanced instruments on the GPM Core Observatory satellite, launched Feb. 27, provide the next...