As thunderstorms form and mutate into the most powerful of storms, called supercells, clouds reaching up to 13 miles above Earth's surface can produce damaging hail and play host to tornadoes. When McCarthy looked that morning, the satellite images showed nothing to worry about. Next he checked wind data. Each station is a collection of antennas that measures 40 feet by 40 feet square and resembles a chain-link fence. Meanwhile, southerly surface winds pumped in more moist, warm air from the Gulf.
Convection is the process of energy transfer by movement.
Inside the radar station dome, technician Frank Hewins inspects the Doppler dish, which sends out electromagnetic pulses 2,600 times per second. The radar is so sensitive it can detect migrating birds and even swarms of insects. But another storm soon emerged in southwest Oklahoma. A huge mushroomlike cloud showed up on satellite images that arrived just after 4 p.m., indicating the second storm was developing into a supercell. The meteorologists' focus shifted across the street, to the Norman National Weather Service Forecast Office, one of the 121 local forecast centers around the country that are responsible for communicating weather warnings to the public.