• Publication: 2014-04-23
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          Tornado Warning False Alarms: National Weather Service Upgrades to Impact-Based Warning System
          Most tornado warnings are false alarms. However, the National Weather Service and the research community is working to solve that problem.
          Prior to the April 3-4, 1974 Superoutbreak, warnings were typically issued only after a tornado was already confirmed. Today, tornado warning lead time —the time from the warning is issued to the time the tornado occurs — averages around 15 minutes. There is no telling how many lives have been saved over the past few decades thanks to advance notice.
          The bottom line: Meteorologists detect tornadoes when they actually occur quite well. So what's causing all the false alarms?
          Striking the Balance
          There's a delicate balance between trying to detect and warn for every single tornado while keeping the number of false alarms low. The more tornado warnings you issue, the higher chance of a false alarm, which increases public complacency.
          "We want to err on the side of caution. It's not an option to miss one," said Chad Omitt, warning coordination meteorologist at the National Weather Service forecast office in Topeka, Kan. "We do the best we can to catch every tornado before it happens."
          On the other hand, less warnings would, in theory, lessen false alarms.
          "What risks are we willing to swallow in order to take a step back and not go after every weak tornado?" asked Omitt. "That's a conversation we have not yet had with emergency managers, elected officials and the media."
          "A lot of these (weak, particularly EF0) tornadoes may be on the ground for a minute or two and do not kill." We'll come back to that point later.
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