What Is Tornado Condition (TORCON) Index?

What Is Tornado Condition (TORCON) Index?

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The unpredictability of tornados can be the cause of anxiety for residents. They can quickly wipe properties and lives away and then just disappear. 

But there’s a tool called the TORCON Index that is used to measure the likelihood of a tornado occurring. TORCON can help you prepare for disaster and keep you and your family safe. Read on to learn just what the Tornado Condition (TORCON) Index is and why you should use it. 

What is a Tornado?

Tornado in the American plains

A tornado or twister is a weather phenomenon characterized by high-speed winds rotating in a single column. The funnel-like clouds can spin air up to 250 miles per hour with a 50-mile distance. 

The main recipe in the formation of a tornado is a thunderstorm. Warm air rises, and cool air falls with hail or rain. This fluctuation can lead to air currents spinning in the cloud. From a horizontal movement, it turns into straight-line winds and drops to the ground.

Certain conditions increase the likelihood of a tornado, which means they are predictable. However, there is no perfectly accurate way to tell how severe, when, and where a tornado will form. 

What is a TORCON Index?

TORCON refers to the Tornado Condition Index, a zero to ten rating on a particular region regarding a tornado. The higher the number on the scale, the higher the risk of a tornado. The location’s measurement encompasses an area within fifty miles. The number also indicates the circulation of the air in the tornado funnel and the risk of warm weather mass accumulation. Each numeral designates a percentage of the risk. 

For instance, a TORCON index of two means the likelihood of severe storm conditions in this location is only 20%. And a TORCON index of five means a 50% chance of a tornado within 50 miles of the area. A specific example would be the weather report of the Weather Channel in 2018. The updated prediction is that the TORCON level for North Alabama is 7. This level denotes a 70% chance of tornado development. 

The National Weather Service does not recognize TORCON as an official weather term or a unit of measurement for tornadoes. Other weather experts like the National Oceanic and Atmospheric Administration do not use this term. Instead, they use tornado watches and warnings.

Unlike a TORCON Index, the warning is simply an alarm that there is a high chance of a tornado producing in the area. The threat of tornadoes may have been noticed on the weather radar or in person. 

Why Use the TORCON Index?

One uses the Tornado Condition Index to predict tornadoes based on three aspects: instability, wind shear, and lift. According to Dr. Greg Forbes, the 1-10 threat scale creator, there is real science behind this tool.

Dr. Greg was a former meteorologist for the Weather Channel. While the channel has created several marketing tactics, the TORCON Index is guaranteed reliable. 

He took advantage of his studies at the University of Pennsylvania to develop the scale. His adviser was Dr. Theodore Fujita, the creator of the Fujita tornado scale. Dr. Greg has plenty of publications about severe weather, including tornadoes.

Here are the three principal dimensions related to severe weather forecasting.


The updraft strengthens as more instability occurs. It only happens when warm air and cold air come in contact and then circulate. Then, a thunderstorm forms as the cold air falls and rises. 

A thunderstorm is a key to developing a tornado, so there must be some sort of instability. It can be weak, moderate, or high as long as it is present. However, instability in itself cannot form a tornado. There must also be a stable lifting force. 

Wind Shear

Rare Formation of Kelvin-Helmholtz & Altocumulus Clouds over South-East England

The two terms to consider when discussing wind shears are the atmosphere and wind. There should be changes in the direction and height of the winds as these contribute to the wind shear. 

Such changes influence tornadic activity. The higher the measurement of the wind shear, the more chance of the occurrence of a tornado. That’s because wind-shearing air currents sustain the tornado’s rotation. 


The lift or lifting force is the last factor contributing to the possibility of the air rising into clouds. This type of force also increases severe weather risk, such as a thunderstorm. 

While instability matters, so does the continuous promotion of rising air in the atmosphere. The Lift also occurs when two masses of air mix. 

There is no perfect ratio of instability to wind shear to lift in creating a tornado. Everything relies on the process of combining the aspects. 

Alternatives to TORCON

Dr. Forbes did not create the TORCON Index Severe to warn of a tornado. That’s why weather experts utilize other systems to predict the chances of a tornado occurring and give warnings. It is the National Weather Service’s job to provide twister warnings. 

There are other sources you can trust for providing tornado watches. Here are some of them. 

National Weather Service

National Weather Service logo

NWS addresses the TORCON Index’s inability to warn of immediate threats of a tornado. They issue warnings for small locations, sometimes even small parts of counties. 

When your location receives a warning, it means they spotted a funnel cloud. Warnings may also tell that their radar caught the possibility of a tornado instead of seeing it in person.

NOAA Storm Prediction Center

The NOAA Storm Prediction Center provides tornado watches when there is a threat of tornado development. When the SPC issues a tornado watch in a specific area, it means the TORCON is at least 3 or 4. However, this is not an official equivalency. 

SPC issues watch “boxes” in any shape on a county-by-county basis. They also provide when it appears on the earth’s surface.

So, Is the TORCON Index Reliable?

RELIABLE written on chalkboard

The TORCON index is backed by science, so we can’t dismiss it as a marketing strategy. However, there are other official sources for tornado watches and warnings, like NWS and NOAA’s Storm Prediction Center.

Got any questions for us? Leave a comment below! And follow these tips to stay ahead of the storm:

  • Refer to NWS, TORCON index, and NOAA for tornado updates.
  • Get a complete weather station like the Davis Vantage Vue to monitor the weather.
  • Designate a safe room or tornado shelter. 

And for more great tips, check out our guide to using a rain gauge.

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