DES MOINES —
New warning tags for the National Weather Service went into effect today in an attempt to better clarify the information that goes out to the public.
There are three basic tags: The tornado tag, tornado damage threat tag, and the tornado tag for severe thunderstorm warnings. They apply in different situations.
The tornado tag is the simplest and will probably be the most frequently used. It indicates whether a tornado in a warning is indicated by radar or confirmed by observers. It may not sound like a big deal, but people react differently to a tornado warning when they know the tornado has been spotted on the ground.
Tornado damage tags will be used less frequently. The reason is simple enough: Most tornadoes aren't on the ground long enough or strong enough to need one.
The tag for severe thunderstorm warnings is a bit different. Experts have long said tornadoes can happen with little to no warning from virtually any severe thunderstorm, but are much more common with specific types. So this tag attempts to bridge the gap, warning people that the potential for a tornado exists when forecasters aren't quite confident enough to issue a specific tornado warning.
Here's a breakdown with a description from the National Weather Service:
Tornado Radar indicated
Evidence on radar and near storm environment is supportive of a
tornado, but there is no confirmation.
A tornado is confirmed by spotters or through other means.
Tornado damage threat tags
Use most of the time, when tornado damage possible within the warning
polygon. Tornado duration generally expected to be short-lived.
Tornado damage threat considerable
There is credible evidence that a tornado, capable of producing
considerable damage, is imminent or ongoing.
Tornado damage threat catastrophic
This is the same as a tornado emergency! A severe threat to human life and catastrophic damage from a tornado is occurring. Only used with a reliable confirmation of a violent tornado.
Tornado tag in severe thunderstorm warnings
A severe thunderstorm has potential for producing a tornado although forecaster confidence is not high enough to prompt a tornado warning.