waterspouts, landspouts, betwixt and between

[Jason Harris]

I can't post on the tornado report for Ventura, CA to add to the discussion (I assume because of my junior status), but I found a relevant article that claims yes, the Point Magoo tornado was a waterspout that came on land.
http://www.venturacountystar.com/news/2008/jan/25/small-tornado-strikes-point-mugu/
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How often have people observed this? And at what mph do waterspouts max out at? I've read waterspouts as often starting at the surface and developing upwards, but can't they also connect to a wall cloud? And is the distinction always clear between a waterspout starting rotation on the surface and a tornado from a wall cloud that comes down to the water? So, when is it a waterspout and when is it a tornado that touches down to the water?
As for landspouts, aren't these funnels that touch down that don't come from a wall cloud? What's the strongest landspout ever recorded? And when is the waterspout a landspout over the water?

I've copied the article down below here about Point Magoo, but if you go the link you can check out some storm pics too (pics 5 & 6 show some decent amounts of hail fell--particularly for Southern CA in January!).
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A waterspout came on shore as a weak tornado Thursday night and tore the roof off an empty air station hangar at the Naval Base Ventura County at Point Mugu, authorities said.

An air traffic controller at the base spotted the tornado about a quarter-mile away, said Bill Hoffer, a spokesman for the National Weather Service in Oxnard. The waterspout's vortex was reportedly almost horizontal as it was pushed on shore by gusting winds, he said.

The tornado touched down shortly after 7 p.m., ripping off the hangar's roof and scattering debris on the runway, according to CS3 Lester Brown, who works on the quartermaster's deck. No one was injured.

Hoffer said waterspouts have been forming periodically throughout this week's storms, and the National Weather Service has issued a special marine warning that any thunderstorm could produce a waterspout, gusty wind, high waves, lightning and heavy rain.

The National Weather Service issued a tornado warning Thursday night for southwest Los Angeles County, including Malibu, Pacific Palisades and the Topanga area.

— The Associated Press contributed to this report.

 

[Keith Mullen]

This is a fun topic - loaded with debate, semantics and some controversy.

I'll just throw my views on the table and let others pic them apart:

How often have people observed this & at what point do they max out?

Waterspouts are very, very common. Period. The point they max out at? If a landfalling waterspout is being generated from a powerful meso... then it is probably going to max out theoretically at most EF5 - as it is a violent tornado that touched down over water.

Now trying to draw a line and physically label a vortex "definately a landspout or waterspout"... I guess the best definition that would appease most would be: a tornadic circulation in contact with the ground being initiated by misocyclonic rotation / lower level rotation in a non-mesocyclonic storm / cold core setup with just enough local shear factors to allow small-scale tornadogenesis.... or other "Non-Mesocylonic - Supercellular" initiation/structure.

Waterspouts and landspouts are "usually" not terribly impressive by the above standards (excluding supercell waterspouts), normally short lived, and normally not "too" violent.

BUT,... technically speaking by definition, all are tornadoes. waterspout, landspout, tornado, etc...

Trying to fit each peg into a different hole to really delineate each has always been a sore point of discussion with some - as you would really need to have the NWS/NOAA and all other weather entities re-define and delineate these to put an end to discussion. Not going to happen any time soon.

Is it over water? waterspout.
Is it from a storm with obviously moderate rotation and apparently well defined over land? tornado.
Is it from a cold pool aloft creating temporary conditions favorable conditions for moderate storm activity and not from a meso? Landspout.

....and then of course the reality: there are a million shades of grey where each draws their own line.

Have fun with this! Sorry if this wasn't much help.

 

[Keith Mullen]

...and one would think that this would have garnered more debate as well... lol.

Oy Veh!.... lol.

 

[Jason Harris]

Thanks for the input Keith. I wonder what you think of the idea of the wind being weakened by the water, as indicated in this Time article; I've included a few other details in the copy/paste because the weather folkloric remedies are rather entertaining:

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Ancient mariners regarded waterspouts as dragons, tried to disperse them by stamping their feet, shouting, beating drums, clashing swords. When gunpowder came into use, sailors tried to break the columns by shooting cannon. The spouts are chiefly vapor but may contain fresh water condensed from the cloud or salt water sucked up from the sea. Like tornadoes they are atmospheric vortices caught by conflicting air currents, with partial vacuums at their cores. In general, however, they are much less violent than the average tornado, do damage only by dropping their loads of water. If a land tornado passed out to sea, it would become a waterspout, but the water sucked up into the column would nullify to a great extent the destructive force of the vacuum.

from (1936 article it seems):
http://www.time.com/time/magazine/article/0,9171,762300,00.html?promoid=googlep

 

[Keith Mullen]

Well there are some truths to the effects of large bodies of water inhibiting the strength of some waterspouts (to a degree). The effects of inflow interacting with the water surface, the waters temp - and possibly cooling and placing a bit of a "choke" on the updraft by pulling up cooler waters/air than what was available upon initiation.

Water itself getting sucked into the tornado and weakening it? Just that particular part of the equation alone only holds a little bit of interest to me, as slow moving HP's do get their own rain wrap & I'm sure they recycle more than their fair share of water in the right environments... Now have that same tornado pass over a large cold lake, I am sure there would be some effect on it. Just how much? Couldn't even guess.

I'm sure others who have actually studied this kind of phenomenon / theory could drop a more learned opinion than my basic assumptions.

 

[Martin North]

There are two 'main variations' of Waterspout. The Mesocyclonic and the Convergence driven.

They are both types of tornado, and can be strong (meso) or weak.

It could be argued that the convergence driven Waterspout is much the same as a Landspout.

The Mesocyclone tornado over water obviously remains being called a Waterspout as this best serves maritime and NOAA warning(s) interests. And sure everyone knows what a Waterspout is....and one word is better than three.

There are those who want to drop the term 'Waterspout' altogether. I'm sure they will show up in due course.

 

[Keith Mullen]

Well, I suppose I COULD have kept it that simple...

But I am a glutton for punishment.

Thanks Martin for essentially summarizing my statements down to something more tangible.

I also have my own theories on small scale tornadogenesis - (EF0/EF1) occurance in atypical setups... but I am not quite prepared to go there.

Out of the few succesful chases I have even really endeavored on, I guess you could say I have about a 20% rate - as those that I have travelled more than 50 miles on...

... I have personally tracked only two tornadoes, and followed one meso (about 2 minutes after an F2 - which I couldn't see due to huge douglas firs)...

The first was just East of Eriswell, UK (Suffolk) back in 1992, The next (meso chase) was the Tenino, WA F2 (05?), then an F0 in my own backyard - Lacey, WA 2007...

But let me tell you, living in Central Utah, and visiting Wyoming, and Idaho, and Kansas... some of the more impressive storms I have ever witnessed were those along the SE coast of England... so don't brush those storms off so easily all..

anyway, just rambling.... Keith

 

[Paul Knightley]

I think problems arise with the term, "waterspout", when strong tornadoes develop at sea, or move out to sea...we then have to contend with the ludicrous term, "tornadic waterspout".

We know that tornadoes have different intensities, but that is due to the parent storm rather than the tornado. All violent class tornadoes (EF4-5) develop beneath mesocyclones associated with powerful supercell storms. Weaker tornadoes can develop beneath mesocyclones but also beneath non-mesocyclonic storms. But they are still tornadoes - that is my point. I am more than happy for tornadoes to have pre-descriptors - e.g. non-meso tornado, misocyclone tornado, mesocyclone tornado, convergence zone tornado, etc, based on what kind of environment they have developed in. However, they don't need to be classed by where thay have developed. They should only be classed by how they've developed.