Meteorologists forecast tornadoes through the measurement of temperature, air speed and pressure conditions to monitor atmospheric conditions, explains LiveScience. Meteorologists use data during inclement weather to predict the probability of a tornado, but they do not know with complete certainty when or where a tornado will occur.
Satellites, radar and weather balloons provide the data for meteorologists to forecast tornadoes and create alerts for the public. Meteorologists track large storm systems containing elements with the potential to create tornadoes, such as certain types of clouds and hail. The moisture in the air and the combination of high-pressure and low-pressure systems also help experts gauge the likelihood of a tornado. This information produces a radar map, providing the data that meteorologists feed into computer models. Data within the models give meteorologists a way to view a storm’s path and predict the probability of cloud rotation.
Since the forecast of tornadoes requires extensive scientific equipment, national services do much of the predictions in the United States and disseminate the information to local areas. Meteorologists at the National Weather Service declare tornado watches and warnings when enough data points to the possibility of a tornado. Once these have been issued, local meteorologists will include the use of eyewitness reports of possible tornado touchdowns and cloud rotation to refine their predictions.