There, Forbes studied under tornado scientist Ted Fujita and his thesis was regarding the 1974 Super Outbreak where he and Fujita did aerial and ground investigations documenting tornado paths and furthering ideas of the tornado family and of multiple-vortex tornadoes. It was with those data he confirmed in a 1981 article that the hook echo is an excellent clue on a weather radar for the development of tornadoes.
Forbes's research was centered around the 1974 Super Outbreak, which he studied with Fujita. Their findings on tornado paths and families led to his confirmation in 1981 that the hook echo is a useful tool for weather radar when predicting tornadoes.