Tornado Warnings are issued to enable the public to get out of harm’s way and mitigate preventable loss. NWS forecasters issue approximately 2,900 Tornado Warnings per year, primarily between the Rockies and Appalachian Mountains. Tornado Warning statistics are based on a comparison of warnings issued and weather spotter observations of tornadoes and/or storm damage surveys from Weather Forecast Offices in the United States. The false alarm ratio (FAR) is the percentage of times a tornado warning was issued, but no tornado occurrence was verified. Most tornadoes cannot be visually tracked from beginning to end and post-storm damage surveying is the official method with which the NWS categorizes tornado characteristics (intensity, path length & width) but must rely on radar data to estimate the timing of the tornado track.
*Please also note that a FAR is the number of false alarms per the total number of warnings. If an FAR actual is higher than the target, then the target has not been met. If the actual is the same number or less, then it has been met or exceeded.