Don’t Be Fooled: Identifying True Tornadic Potential

Today, I’ll show you how to tell when a lowering has a real chance of producing a tornado.

For new storm chasers, one of the biggest challenges is knowing what you’re seeing. At first glance, it might seem easy—just look for clouds that resemble textbook images. But real storms rarely match the textbooks. A wall cloud that could produce a tornado can look very similar to a harmless lowering.

Understanding which lowerings have real tornado potential helps you position yourself for the best intercept, and it may even prevent you from missing a tornado.

The challenge? Telling these lowerings apart—even experienced chasers sometimes get it wrong, sometimes leading to missed opportunities.

Non-tornadic lowerings usually form near a downdraft.  Tornadic lowerings often develop where updrafts and downdrafts meet.

I’ll never forget it.  It was one of the saddest things I’ve seen while chasing.

May 4, 2003.  Dozens of chasers had pulled over on Highway 60, pointing excitedly at scud tags about a mile to our north, some filming as we drove by. What they missed, though, was a half-mile-wide tornado churning just beyond the hill, slightly out of view. They were on the right storm at the right time but not in the right position.

I’ve seen scenes like this happen with many storms—many chasers simply don’t know where to look.

To make things even more challenging, obstacles often block a clear view. Here are a few common ones that can make it hard to spot a circulation within a storm:

• Obscuring clouds
• Rain curtains blocking view
• Dense trees and foliage

Knowing where to look—and what to ignore—makes all the difference in spotting a tornado. You can train your eye to see past obstacles and find the real thing. But first, you need to know where the fake-outs tend to appear.

Where to find “fake-out” circulations

Fake circulations can appear in various spots around a storm, typically linked to downdrafts, which are common near supercells.

I’ve marked three areas on the supercell diagram where look-alike circulations commonly appear. Here’s a brief description of what to expect in each area. 

Fake-Out Area #1
This area is influenced by the rain-cooled rear-flank downdraft. You might see a small funnel shape or scud clouds hanging beneath the main cloud base. These can look convincing, especially to newer chasers. I used to call these scud tags “flanking line garbage,” and they’ve tricked me more than once. This was the exact phenomenon that misled those unfortunate chasers in Missouri.

It’s worth noting that this area can occasionally produce real tornadoes, though it’s rare. Landspouts often form here; these are tornadoes created when an existing vertical circulation is stretched by a thunderstorm updraft, typically along the supercell’s flanking line. Landspouts are relatively uncommon and don’t usually develop beneath a ragged lowering.

Another way real tornadoes can form in this area is through a counter-rotating vortex that generates anticyclonic tornadoes—an extremely rare event. In fact, I’ve only seen two storms with anticyclonic tornadoes throughout my entire chase career! So that fuzzy lowering beneath the flanking line is unlikely to be the one you’re looking for.

Fake-Out Area #2
Close to the real circulation, this area is trickier to diagnose. Here, the cool air from the rain and hail core (forward-flank downdraft) moves into the main updraft from the north. Lowerings in this area may sometimes indicate a forming tornado, though these features rarely produce tornadoes themselves.

That said, these lowerings often "feed" into the main circulation from the north! So, it’s not uncommon for these features to indicate that something significant is developing just to their south.

Fake-Out Area #3
This region often has remnants of old circulations or just rain-cooled air, resulting in a lot of “scary-looking clouds.” Most of the time, lowerings here don’t turn into much.

However, if a tornado is already dissipating, it might occasionally move into this area, making it a rare spot for real activity. But this is an exception, not the rule.

Where to find the real thing

So, where’s the “real” circulation? After 25 years of chasing, I can say it’s typically where the rear-flank downdraft meets the forward-flank downdraft.

This aligns with the textbook understanding that tornadoes usually form at the storm’s center of circulation, close to the rain and hail core.

If you spot two lowerings—one along the rear-flank gust front and another closer to the rain—the one near the rain is usually the real deal.

 In a storm-relative sense, tornadoes can form in various spots. But knowing where they’re most likely to develop helps you make the most of every chasing opportunity.

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Well, that's all for now.  Hope you enjoyed it!

- Gabe Garfield

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