While watching The Weather Channel during periods of severe weather, you may have heard meteorologists talking about the TORCON Index for a specific area. What does TORCON mean, and why is it useful? Below we hope to answer some of the questions you might have.
TORCON stands for Tornado Condition Index. On a scale of 0 to 10, a specific region is given a number, with higher numbers indicating a higher risk of a tornado within 50 miles of the given location. For example, a TORCON of 2 would indicate a low chance (20%) of tornadoes, while a TORCON of 8 implies a high probability of tornadic activity (80% chance).
Who Created the TORCON Index, and Why Is It Useful?
The TORCON Index was created by retired Weather Channel meteorologist Dr. Greg Forbes. A severe weather expert, Dr. Forbes, aimed to simplify how meteorologists communicate severe weather risk to the public with an easy to understand scale.
To see more information on what TORCON is, watch this video narrated by Dr. Forbes himself.
While The Weather Channel has done a few things over the years, which appear to be more of a marketing gimmick than actual science (such as its decision to name winter storms), the TORCON Index has real science behind it.
Dr. Forbes has published several papers on severe weather and worked under Dr. Theodore Fujita—the man that created the Fujita Tornado Scale. His experience there, and in research projects with Penn State University played a large part in his continuing interest in severe weather.
The TORCON index is a combination of three primary factors in severe weather forecasting: instability, wind shear, and “lift.” Below is a brief explanation of what these terms mean.
- Instability: For thunderstorms to form, the air needs to be able to rise. Warm air at the surface with cold, dry air aloft creates instability, allowing air to rise and clouds to form.
- Wind Shear: Tornadoes need rotation in the atmosphere and wind that changes direction with height. The more wind shear, the higher the risk of rotating thunderstorms, called supercells.
- Lift: While instability is a crucial factor, if the atmosphere further promotes rising air, it can enhance thunderstorm development. This occurs along fronts or where two air masses collide.
Dr. Forbes’ idea was to take these complex variables and simplify them. The Weather Channel owns the TORCON index’s rights, so the scale isn’t used elsewhere.
Alternatives to TORCON
While there is a scientific basis for Dr. Forbes’ TORCON index, there are other official sources that provide tornado watches and warnings. These alerts are just as accurate to gauge tornado risk and to receive up-to-the-minute severe weather information.
Tornado Watches From the NOAA Storm Prediction Center
The National Weather Service’s Storm Prediction Center issues tornado watches anytime there is a threat for tornadoes to form. While there is no stated equivalency with TORCON, an area where the SPC issues a tornado watch likely has a TORCON of at least 3 or 4. Watch “boxes” can take any shape and are issued on a county-by-county basis over a large area.
To review what a tornado watch means, one is issued when conditions are favorable for a tornado to occur in and near the watch area. When a tornado watch is issued, be prepared by checking forecast updates, knowing where to take shelter, and monitoring sky conditions for tornado warning signs.
Tornado Warnings From the NWS
One thing the TORCON index is not intended for is to warn of the immediate danger of a tornado. That’s the job of tornado warnings issued by the NWS. These are issued for small areas, sometimes even small portions of counties. In this case, a warning means that a funnel cloud tornado has been spotted or radar indicates a high likelihood that a tornado may be on the ground.
While the TORCON index is useful and is more than just smart marketing, I still highly recommend you check official National Weather Service’s forecasts instead. Also, I recommend purchasing a weather radio if you live in an area prone to severe weather. Please take a look at our reviews and buying guide to find the best weather radio here. These radios will deliver warning information the fastest—even faster than a smartphone app notification.