The Science Behind Tornado Warnings And How They Are Used

Tornado Warning
  • Tornado Warnings are much different than the typical “severe weather” or “thunderstorm” warnings.
  • Tornado warnings are issued based on what storm spotters recognize and what meteorologists interpret from radar and computer algorithms.
  • Tornado watches are issued as a precautionary measure whereas tornado warnings require action due to an actual tornado spotting.
  • Tornados can form in a matter of minutes, although the Joplin tornado in 2011 formed much quicker.

If you have a smart device, you’ve probably seen a weather notification pop up on the screen such as “severe weather warning” or “severe thunderstorms” from time to time. Depending on where you’re located, you may have even seen a “tornado warning” prompt appear as well. But what is a tornado warning and how do meteorologists detect them?

How Are Tornado Warnings Detected

Storm spotters are those that are specifically trained to recognize weather patterns and conditions conducive to tornados. These storm spotters can work for emergency services or be local citizens that have an acute sense of severe weather. If a possible tornado is spotted, they’ll make a call to the National Weather Service in order to relay their information.

Forecasters are meteorologists that predict future weather events based on computer algorithms that take data received from Doppler radars. These radars can detect rotating updrafts inside a supercell called mesocyclones. These mesocyclones are often associated with “hook echos.” These hooks—named for their hook-shaped radar depiction—designate conditions in which a tornado is most likely to form.

The National Severe Storms Laboratory (NSSL) also uses Dual-polarization radar technology that can determine the presence of debris near a severe storm. This allows meteorologists to confidently predict that a tornado has touched down.

Tornado Watch vs. Tornado Warning

A tornado watch signals that all residents within the designated warning area should take precautions. According to what meteorologists, radars, and storm spotters are noticing, the weather patterns are favorable for a tornado. A tornado watch indicates the possibility of a tornado rather than the presence of one. Tornado watches are issued by the Storm Prediction Center.

A tornado warning is much more severe. When a tornado warning is issued by the National Weather Service, those nearby should take action to protect themselves and their property. A tornado warning indicates that an actual tornado has been seen and reported by either a storm spotter or local citizen.

The Quick Formation of Tornados

A tornado watch can turn into a tornado warning in a matter of minutes. Remember that a tornado warning is only issued once a tornado has been spotted. It doesn’t take long for a tornado to form and touch down. Tornado watches are given so that you can be prepared for when a real tornado hits before it’s too late.

The Joplin tornado in Missouri in 2011 materialized from nothing to 1 mile wide in approximately 20 seconds. It reached wind speeds of over 200 mph as it devasted neighborhoods, killing 158 people and injuring another 1,150.  It was reported that many residents ignored the tornado warning that was issued.

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Written by Bryan Brammer