How do forecasters know which way storms are going to move, such as 'Sandy' turning inland?
Forecasters study data-a lot of it. Surface weather observations from land-based weather stations, buoys and ships over the ocean...and upper air data that comes from weather balloons, commercial jets and satellites. All that data is also plugged into complex mathematical equations, which are solved by computers to project weather conditions in the future for various locations. We don't use just one computer model, but several, each using slightly different approaches. Meteorologists look for consensus between the forecast models, and certainly changes in trends...as they use these models...or computer simulations...to forecast the weather.