What is "a developing tornado"

[rdale]

Pulled this out of the DISC thread since it wasn't specific to yesterday...

Matthew reposted info on "spotters indicating a developing tornado" in the NOW thread, and I'm curious what that means. In my mind, either it IS a tornado or it IS NOT a tornado. So what is a "developing" tornado? Since we don't know that every funnel is going to reach the ground, how do you know what cloud feature is going to develop into a tornado and what cloud feature will not?

Is it just a funnel cloud half-way down? A rotating wall cloud? Rotation in the mid-levels?

- Rob

 

[Josh Murfield]

I would guess when someone mentions a developing tornado they do mean a funnel. If you've been watching a wall cloud and then see a funnel starting to pull down from it, that to me is one of the later stages of tornado development (or birth, whatever you want to call it , even though it may never actually touch the ground becoming an actual tornado.

 

[Brian Emfinger]

I agree that doenst make a lot of sense to say "reporting a developing tornado". Its either a tornado or its not. They must know more than I to be able to say a tornado is certainly developing from a particular storm. We all see lots of wall clouds and storms that we would consider supportive of tornadic intensity that dont produce (several yesterday) so how would you know when its going to produce or not? And of course the opposite is true as you can have tornadoes form from storms that looking at you wouldnt think would produce a tornado.

 

[Brian Stertz]

I would have to say that an experienced chaser truly can tell when a tornado is imminent. Likely by the time the report of a developing tornado is called in, the tornado is on the ground already. So time sequence wise it would be wise to call in the report as a tornado or at very least a funnel cloud for the warning purposes.

 

[Skip Talbot]

This was part of a NWS issued warning wasn't it? Let's remember the target audience of warnings: the general public. So if several spotters are reporting increasingly organizing wall clouds, some with rotation, and/or funnels, it makes sense to relay to the public that a tornado may be (or is) developing. Not too many ordinary people actually know what a wall cloud is, so reporting one over the weather radio might be meaningless. The job here is to get the word out that a tornado may be imminent, not to be scientifically accurate.

 

[rdale]

I don't agree with your statement. The target audience of the TEXT of the warnings though is TV mets & EM to pass that info on to the public... VERY few Joe Publics get that part of the warning. So if the TV guy knows there's a rapidly rotating wall cloud, he can emphasize that. If this "developing tornado" is just some mid-level rotation, I'm not going to push nearly as hard.

I see many offices also say "spotters report a severe thunderstorm" without saying what happened... Was it 3" hail or a 90mph gust? I think those differences need to be indicated too.

So time sequence wise it would be wise to call in the report as a tornado or at very least a funnel cloud for the warning purposes.

I _strongly_ disagree with that... If there is nothing happening on the ground, do NOT call it in as a tornado just because you are worried about communication delays.

 

[rdale]

...and the kicker is that (at least per preliminary reports) there was no tornado to come from this storm... A separate cell in the county has a law enforcement report of a touchdown but no damage.

 

[Robert Dewey]

I don't see a problem. I can understand that "developing tornado" is probably similar to "a tornado is imminent" - however, I do agree that it would be more beneficial if the NWS would put spotter reports in (or at least narrow down the expected event type). When I see a bow echo blasting east and see "severe thunderstorms can produce large hail and damaging wind", I really think the wind aspect should be played up a bit more (i.e. expect winds up to 70MPH, or "spotters reported 80MPH in PickAName Township"). Spotter reports make an SVR or TOR more credible IMO.

 

[Willie Dines]

I think that the referrence of "A Developing Tornado", might actually be a funnel cloud that is barely touching down, e.g. only beginning to whip up dirt or debris, but the funnel still not completely on the ground.

I do agree though, that a report should be either a funnel cloud or tornado, it's best to keep things simple, especially when it comes to giving out warnings, the simpler and straight forward the warning, the less time taken to give the warning and more time for people to get to their basements, storm cellars, etc

Willie

 

[Andrew Herron]

If there is a funnel and there is a debris cloud, by NWS definition, that is a tornado.

No debris cloud, no tornado, that simple.

I think that the referrence of "A Developing Tornado", might actually be a funnel cloud that is barely touching down, e.g. only beginning to whip up dirt or debris, but the funnel still not completely on the ground.

 

[Willie Dines]

If there is a funnel and there is a debris cloud, by NWS definition, that is a tornado.

No debris cloud, no tornado, that simple.

I know that, but if a spotter is calling it in as a developing tornado, then they might be typing up the information being passed on by from the spotter, but I agree with you wholeheartedly, and I previously mentioned that it should either be called in as a Funnel Cloud or Tornado

Willie

 

[rdale]

If a spotter said "developing tornado" to anyone with weather knowledge he would immediately be asked to clarify... The same response you'd get if you said "winds are strong"

 

[Terry Tyler]

i think its more of a conflicting terminology issue...whether or not it is on the ground...i would say a "developing tornado" is just as the name implies...a developing tornado...

it might not make it to the ground or anything, but its beginning to form and if it continues to develop, then it will become a full-blown tornado...i guess you could call any funnel cloud a "developing tornado" but then again...its not a tornado yet so...

IMO, a developing tornado is a "developing" tornado...all kinds of things develop, but not always come out to be what they were gonna be...

the same can be said for tornadoes...

 

[beaudodson]

I don't agree with your statement. The target audience of the TEXT of the warnings though is TV mets & EM to pass that info on to the public... VERY few Joe Publics get that part of the warning. So if the TV guy knows there's a rapidly rotating wall cloud, he can emphasize that. If this "developing tornado" is just some mid-level rotation, I'm not going to push nearly as hard.

Hmmm on the target audience. Actually a lot of people hear the warning on NOAA Weather Radio or directly through the Radio-EOS broadcast. This WOULD include the text of the "developing tornado" - I would say a huge number of people do hear the actual text. Depends on whether you are watching tv or not. Thousands will hear the warning on their weather radios or radio.

 

[rdale]

Even if they do get the entire warning shown or read to them, do they listen to the entire text of the warning? Do they know the difference between "doppler radar indicates" or "NWS meteorologists detect" or "developing tornado"? If you asked them 30 seconds after listening what exact phrase was used, would they remember? No way. So if you say 10% of the public gets their info this way, the rest from tornado sirens and TV, I still don't call Joe Public the primary audience of the text details.