The infamous 1925 Tri-State Tornado Outbreakthe longest-lasting on recordinspired a gradual, painstaking movement toward better tornado forecasting and more timely warnings. But gains have been measured in minutes, not hours. The average lead time for warnings, which for years was 6 minutes, is now up to almost 12.
Forecasters gather data from satellite imagery, radar, surface weather stations, weather balloons, and lightning detection networks. Doppler radar can detect strong rotation within a storm, information useful in predicting the likelihood of a tornado. NEXRAD (Next Generation Weather Radar) is a computerized Doppler system especially good at tracking and analyzing tornado-producing storms.
In the United States, two government agencies located in the heart of hurricane country provide research and timely guidance concerning hazardous weather. The National Severe Storms Laboratory conducts long-term research. The Storm Prediction Center, working with National Weather Service field offices around the country, offers short-term predictions and other guidance for those in the way of harm when the wind starts spinning.