Warnings 15
Warnings 15 : The hazard (tornado, flash flood, etc) is imminent. The probability of occurrence is extremely high. Warnings are issued based on eyewitness reports or clear signatures from remote sensing devices such as radar and satellite. Lead-time for thunderstorm type events is generally 30 minutes or less. Lead-time for hurricanes, river floods, and winter storms can be 6 to 18 hours