How do you know when tornadoes are going to happen?

Answer 1

Meteorologists look at various conditons in the stmosphere such as temperature, pressure, humidity, and wind speed and direction at different levels of the atmosphere and in different locations and use computer models to see how conditions might come together. Given the right setup with a sufficient supply of warm, moist air and the right setup of wind shear you could see the potential for tornadoes. The Storm Prediction Center issues severe weather outlooks discussing the potential for tornadoes, severe hail, and severe wind gusts from thunderstorms. Maps and discussions of these outlooks can be found in the link below. The percentages shown are the chances of a given severe weather event ocurring within 25 miles of any given point. If a tornado outlook covers any significant portion of the map, then the will probably be at least a few weak tornadoes. If a tornado watch is issued, that means conditions in a general area are favorable for tornadoes to form over the next few hours. Most of the time a tornado watch is issued at least a few tornadoes will probably touch down, though most areas under the watch will not come under an immediate threat. If a tornado warning is issued that means that a nearby thunderstorm is either likely to produce a tornado or that a tornado has been spotted. While some tornado warnings do turn out to be false alarms, it is best tor err on the side of caution and take cover. Many people killed or injured in tornadoes were those who did not heed the warnings.