The first tornado warning was issued on March 20, 1948 for a storm that produced a tornado in the Oklahoma City area.
If a tornado has been detected or spotted then a tornado warning is issued.
If a tornado is spotted a tornado warning is issued.
Tornado warning
a tornado warning would be issued if it is in your county and a tornado watch if it is out of your county.
Such a thing is impossible to predict. A tornado warning itself is a prediction that the threat of a tornado is imminent. As soon as signs indicate that a tornado warning is warranted, then one is issued. So there is no way of nowing when a tornado warning is going to be issued until it actually happens.
Usually a watch is issued first, and then warnings are issued as tornadic storms develop. However, occasionally a tornado warned storm may develop without a tornado watch.
No, a tornado watch is issued when the general weather conditions can produces tornadoes. If a tornado is spotted a tornado warning is issued.
If a thunderstorm is capable of producing a tornado in the immediate future or if a tornado has been detected then a tornado warning is issued. If general conditions are favorable for tornadoes but there is not necessarily an immediate threat, then a tornado watch is issued.
If a tornado is spotted or is detected by radar, then a tornado warning will be issued.
A tornado warning is an advisory that is issued when a tornado has either been spotted or detected or that a thunderstorm in the area is likely to produce a tornado soon.
A tornado warning is issued if a tornado or rotation likely to produce a tornado is detected by Doppler radar or reported by eyewitnesses. The warning will include the location of the tornado and the speed and direction of its movement. Information of the warning is broadcast through TV, radio, and various internet sources. In some areas sirens may sound when a tornado warning is issued.
Under these circumstances a tornado warning would be issued.