Do you really know what a tornado is?? Are you sure?

[Kem Poyner]

I know this has been discussed before but this year I have seen so many mistakes. Meteorologists, News Media and recent threads on this site have all demonstrated they do not understand what a tornado is. With so many newbies out there, I think its worth talking about this again. It may save a life.
A tornado is an INVISIBLE rotating column of air that extends from the cloud base to the ground. A pennant shape may or may not be visible. The pennant is made of rain condensation and debris spun up in the center of the invisible column. The pennant may segment, brake-up or disappear just to return giving the idea the tornado is skipping. Tornados do not skip. Once circulation starts on the ground, it stays, doing damage until the tornado occludes.
Sometimes a new tornado may form from a new rotation. The break in the damage path can appear as if the tornado skipped. But not the case.

 

[Jeff Wright]

This may seem off topic, but bear with me.

I remember seeing some footage of what seemed to be a BLEVE

People were running like mad. It seemed to me that they were well away from the rising column of flames. Yet they were already being burned, and the camera was partially melted.

Had an infrared camera been used--the victims would have been seen to have been inside the plume.

The same goes for twisters...

The tornado is wider than the condensation funnel, IF ANY.

Something else to think about.

 

[rdale]

Couple of notes...

I've never heard "pennant" shape used for funnel clouds. I would shy away from that descriptor as pennants are typically horizontal and funnel clouds are vertical.

Once circulation starts on the ground, it stays, doing damage until the tornado occludes.

Correction - it does not always do damage. Sometimes the winds are too weak or there is nothing to "damage".

Here's a good spot to check: The Online Tornado FAQ (by Roger Edwards, SPC)

 

[Kem Poyner]

I borrowed the term "Pennant" from from Charles Doswell III. He used it in his description of a tornado.
I see my post was moved to the "Introductory weather and Chasing section" I am sorry for posting in the wrong section. Since this topic is under debate still by some experts, I thought it was a more advanced topic.

 

[Randy Jennings]

A tornado is an INVISIBLE rotating column of air

I realize the point you are trying to make is that tornados don't have to have a visible funnel and that tornadic winds can extend beyond a visible funnel (which are correct and good points), but your definition is somewhat in conflict with the official definitions:

AMS: Tornado - AMS Glossary
"A rotating column of air, in contact with the surface, pendant from a cumuliform cloud, and often visible as a funnel cloud and/or circulating debris/dust at the ground..."

WMO: MultiTrans Web Log in
"A violently rotating storm of small diameter; the most violent weather phenomenon. It is produced in a very severe thunderstorm and appears as a funnel cloud extending from the base of a Cumulonimbus to the ground."

NWS: Glossary - NOAA's National Weather Service
"A violently rotating column of air, usually pendant to a cumulonimbus, with circulation reaching the ground. It nearly always starts as a funnel cloud and may be accompanied by a loud roaring noise. On a local scale, it is the most destructive of all atmospheric phenomena."

 

[rdale]

I borrowed the term "Pennant" from from Charles Doswell III. He used it in his description of a tornado.

Pendant? Totally different word

what is a tornado?

Since this topic is under debate still by some experts

Ehh... what sort of debate?

 

[Rick Schmidt]

I looked several words up related to this discussion, and this is one of a few definitions that fit.
pennant:
a short rope hanging from the head of a ship's mast; a pendant

 

[Kem Poyner]

I started this tread because many seem to not know the point I was trying to make (and not making very well it appears). A few weeks ago I was watching an online Live NEWS cast. They were covering a tornado that was about to impact Canton Texas directly. The NEWS caster said, "The funnel is no longer in contact with the ground so it appears the people of Canton may be safe". I could go on and on with similar observations I have seen lately. I did not expect to have my every word picked apart. My spelling has gotten bad the last few years.

 

[rdale]

It’s nothing personal - you came in with a list of items that define a tornado, but that list was wrong. Dr Doswell never used the word pennant when referring to a tornado that I can find - he uses “pendant” which means “hanging from the bottom.” Your example of seeing an online newscaster confusing the funnel and the tornado is quite common, but that’s not the same as “experts are still debating the definition” but more an example of “why you shouldn’t get weather information from non-meteorologists.”

 

[Kannon Kalton]

I don’t like when people see a scud cloud and automatically think its a funnel or something like that. Like yesterday I was on a Tornado Warned Cell and there was a rotating wall cloud spinning up right in front of me, and someone saw a scud cloud in the distance and focused on that instead of the actual rotating wall cloud.

 

[Kem Poyner]

I was chasing when Charles released his "definition" and back then it was debated. Perhaps most agree with him now but still debates go on. For example , Where does the circulation actually start? High in the cloud, mid-levels or a number of small eddies on the ground? To think there are NO debates is like being a pendant in the wind.

 

[rdale]

Where does the circulation actually start? High in the cloud, mid-levels or a number of small eddies on the ground?

Yes All of the above with some more likely than others. But that doesn't change the formal definition of a tornado, and certainly has no impact on chasing. If a cloud hanging below the thunderstorm is rotating and there's damage on the ground below it, it's a tornado.

 

[Jeff Duda]

There is no formal debate as to what constitutes a tornado. While the definition has shifted a little in prior years, it has been only to clarify details that were omitted from prior definitions.

As this thread seems to have flamed up due to some misconceptions and poor word choices, and also seems to have run its course, I am closing it to further discussion.