Fujita, with his cartography skills, was able not only to explain but also to diagram the mesolows, mesohighs, and mesocyclones, the word meso indicating those weather systems up to 250 miles wide. At the same time, he and Tepper created a new language for researchers and provided forecasters with a critical clue for predicting a tornado. Their groundbreaking work was published as Weather Bureau Research Paper No. 39.
