Why do tropical cyclones apparently develop out of thin air - and how can we predict what path they will take?
Answering questions like these is the task of researchers at the US's NOAA weather service on the island of Guam. Many typhoons form here, some 2,000 kilometers east of the Philippines, before sweeping across the western Pacific. The Philippines is currently struggling in the aftermath of Typhoon Haiyan, one of the most powerful tropical storms ever recorded. Tomorrow Today reports on the work of the storm watchers, who despite their increasing knowledge, remain powerless in many respects.