Definition of tornado in question here.

[David Draun]

After tonight's spectacular waterspout roped out, I called the NWS Ruskin, FL to report the storm. It turns out that 40 people reported it. The funnel developed and touched down over Estero Bay and crossed over the island with the resorts and hotels. And there was definitely sand being lifted into the vortex, but the NWS will not call it a tornado due to the lack of damage and the only ground truth was the rapidly rotating sand cloud underneath the funnel cloud. Dewpoints had mixed out heavily today and it was about 95/60 at the time of touchdown. The condensation funnel didn't become whole until it was over the water due to the high dewpoint depression in the area. That's not important, just interesting. The question is: with ground truth of a debris cloud over land, it is by definition, a tornado, right? NWS Ruskin, FL doesn't seem to think so.

 

[rdale]

That was a tornado by any definition used in the meteorological world.

 

[Dan Robinson]

Not only that, but there are many tornado LSRs on record that are described as landfalling waterspouts.

 

[David Draun]

Thanks guys, I knew that all along. But NWS Ruskin, FL is not going to call it one at this time.

 

[Willie Dines]

I think that in this case, the NWS in Ruskin, FL, are going by what the funnel was in contact with, blast, before disspiating, which in this case was water, and so, in that sense, it wwould be called in as a Waterspout, but at the same time, it should've been noted, that it started off as a tornado and so, the finial cassiciation should have been TORNADO - WATERSPOUT, TORRO here in the UK, classifies waterspouts that make landfall or vice verse, in this same manner, and to me, it makes more sense to do so in this way

Willie

 

[Greg Stumpf]

It's unfortunate that all waterspouts are not recorded by the NWS as tornadoes, because this is what they are.

 

[rdale]

Well, not all waterspouts. Just the ones from convective clouds, Lake Erie spouts are not tornadoes.

 

[Greg Stumpf]

Well, not all waterspouts. Just the ones from convective clouds, Lake Erie spouts are not tornadoes.

Huh? Waterspouts from non-convective clouds? Explain.

Joking?

 

[Robert Dewey]

Tornado -- 1. A violently rotating column of air, in contact with the ground, either pendant from a cumuliform cloud or underneath a cumuliform cloud, and often (but not always) visible as a funnel cloud.

That definition would mean any funnel connecting with the ground, beneath a cumuliform cloud, would be classified as a tornado. That would probably include the puffy innocent cumulus clouds that contain a brief spout...

I'd like to think of a TOR as coming from a Cb mesocyclone, versus pure temperature variation beneath a innocent puffy cumulus.

 

[rdale]

Great Lakes waterspouts should not be considered tornadoes.

 

[scott r currens]

Great Lakes waterspouts should not be considered tornadoes.

Why should the name of a particular section of the earth’s surface have anything to do with what we classify a tornado?

 

[rdale]

Scott - it's not the name of the particular section of Earth underneath. It's because the waterspout is caused BY the particular section of Earth underneath. Take away the water, and there's no waterspout (or tornado as you refer to.) Put the exact same environment over land (which happens) and there's no waterspout or tornado.

I realize you've never seen one to be able to tell the difference - but you can hunt down some video and/or stop up here in the fall and you'll KNOW there is a difference between a Lake Erie waterspout and a tornado.

Sometimes the formal definition can be modified by common sense.

 

[Robert Dewey]

Why should the name of a particular section of the earth’s surface have anything to do with what we classify a tornado?

Probably for the same reason that snow coming off of a lake is classified as LES. Sure it's still snow, but the process is entirely different.

Most waterspouts on the Great Lakes occur in the late fall, when the temperatures are in the 40's or 50's, with strong delta-T's over the lake. Hell, you can navigate a boat right through most of them without much more than a puff of wind and some spray... it's not a tornado in the classic sense.

In my book, tornadoes come from a mesocyclone process... anything else (over land) is a spin-up and a result of the terrain.

 

[Greg Stumpf]

Take away the water, and there's no waterspout (or tornado as you refer to.) Put the exact same environment over land (which happens) and there's no waterspout or tornado.

I disagree. The same thermodynamics (sustained updraft) and a convergence zone over land can result in the same non-supercell tornado process.

So, what do you call a Great Lakes vortex that moves on shore and causes damage? Is that not a tornado?

 

[rdale]

No. I use terms that the viewers understand and not wanting them to think it's the same thing as a tornado. When compiling the list of tornadoes at the end of the year - I would not want it in the database.

I call it a waterspout that moved onshore and caused some damage.