tornado or not? 9/15/10 Wichita

[samuel stone]

i took this photo while chasing just wsw of wichita, ks on sept 15, 2010 at this point i am apprx. 4 mi south of the intersection of MacArthur and Ridge rd. looking nw. there is a distinct dirt cloud and what looks like a possible funnel above it. the dust cloud was quick to develop and quick to disapate. the cloud appendage had more staying power but did NOT neccesarily appear to be rotating rapidly if i remember right.

I would appreciate any feedback from anyone especially those who may have been chasing this storm. i know alot of local wichita chasers were on this one.




btw there were multiple reports of small tornado touchdowns in this area. im not entirely sure of the exact touchdown points though. even if you you know nothing about this event i would appreciate feedback if nothing else from a meteorological standpoint. THANK YOU

 

[samuel stone]

http://img541.imageshack.us/i/060av.jpg/
edit- the image shack link is a bigger picture


and this is zoomed in on the area of interest maybe this will help?

 

[Bill Tabor]

This is difficult to impossible to determine without a video showing motion, or being there in person, but regardless when you are there in person and trying to make such a determination it is necessary to refer to the classic definition of a tornado:

[FONT=Verdana, Arial, Helvetica, sans-serif]"According to the Glossary of Meteorology (AMS 2000), a tornado is "a violently rotating column of air, pendant from a cumuliform cloud or underneath a cumuliform cloud, and often (but not always) visible as a funnel cloud."

http://www.spc.noaa.gov/faq/tornado/ "

Note that in the definition no cloud material "funnel" is required. You can have practically invisible tornadoes such as in low dewpoint conditions such as in New Mexico. Also note, and of particular importance the definition states 'violent' motion and 'rotation'. It MUST also be "pendant" or extending below a cumuliform cloud (i.e. thunderstorm cloud) - which implies a 'deep convection' process.

I will also note that on the low end you will get a lot of argument from chasers on this topic because so many don't consider low end weak tornadoes...tornadoes.

Regardless if a feature meets all of these requirements then it is technically considered a tornado.

Concerning your photo... in particular note the lowered appendage above the dirt feature on the ground. This could be a partial funnel cloud 'nipple' associated with inflow / rotation in a cloud of deep convection. Also important you have the dirt feature pretty much right below that. That's a good start for a potential tornado - albeit weak, however we have more to the definition. Do you see any rotation in that cloud 'nipple' area? Is there any rotation with the dirt feature on the ground? It appears that the dirt below may simply be blowing dirt and not rotating dirt. If it was rotating it often takes a see through tubular structure lifting toward the 'nipple' above. You often see blowing dirt beneath such a feature due to RFD (rear flank downdraft interaction). Also does that rotation on the ground appear violent? What is violent? My thought here is that violent by the definition would have to be strong motion in a damage survey later if it struck something to do EF0 damage. An EFO tornado would have estimated winds (after the event) of 65 to 85 mph and the damage it could do is:

[/FONT]"Minor or no damage. Peels surface off some roofs; some damage to gutters or siding; branches broken off trees; shallow-rooted trees pushed over. Confirmed tornadoes with no reported damage (i.e., those that remain in open fields) are always rated EF0."

So the threshold for 'violent' is fairly low end...however it is there. You must make that determination although usually it is a judgement call. If it fits all the above but not F0 strength then it wouldn't be considered a tornado.

Note that such a feature would almost never be a gustnado if it was under the lowered 'nipple' of a cu cloud. Gustnadoes typically occur adjacent to such a cloud - not under them and are associated with shear currents near and alongside the storm. Gustnadoes can sometimes however get run over by a cu inflow area and then contribute to the development of a tornado if conditions are right.

Based on your image it appears very weak. I have seen so many of these features it is unbelievable. Most of my tornadoes are F0 and close to this but showing rotation on the ground in association - apparently tied to the cloud above in some way. This makes sense because records indicate that something like 95% of all tornadoes are F0's. Of course part of that reason is also because tornadoes that don't strike anything or no damage surveys aren't rated except as F0's. Anyway it appears that the feature below your cloud is blowing, not rotating as much as I can see from just a still picture. In that case it would NOT be a tornado. However you were there in person and know what you observed and if there was rotation. If you have any video then you can also review it. Speed it up...slow it down - zoom in if you can. You pretty much would have to have at least video to prove it to others and convince them...however as I said there are those that simply do not count weak low end tornadoes as tornadoes no matter what. These people require a fully condensed funnel cloud. That of course isn't correct, but it is how so many in the community see it. Basically there are little to no bragging rights in the chaser community for F0's. They are better than completely busting though, because you actually pulled something out of it. Don't expect everyone to believe you though. So many will just say it wasn't a tornado, or it was a gustnado.

I hope all that from definition and my experience helps.

 

[Nicholas_Scherber]

I am just speculating of course, but it seems to me that there is a lot of scud in that picture, mostly along the same basic line, which leads me to assume that this is where the RFD is pushing through. Which direction are you faceing? It sort of looks like there is a clear slot behind it, but to me this apears to be on the back side of the clear slot, which once again leads me to believe that it is RFD pushing through. I have next to none working knowledge on this however and am just going off of what makes sense to me.

 

[samuel stone]

thanks guys for the feedback. bill- a video would be nice! but i just had my digital still camera. but from what i remember there was little to no visible rotation. maybe slight rotation in the cloud appendage but hard to say for sure. being able too speed up a video of it would certainly help as you stated. but i dont have that luxury and the fact that the dust cloud was breif and showed no real rotaion or even upward movement i would have to take the conservative route and say it was no tornado. like you said it wouldnt be much to brag about anyways! but thatnk you for the information and feedback MUCH appreciated, i am glad we have guys like you on stormtrack willing to give more experienced feedback on these types of questions.

Nicholas- you may be onto something as there were some really crazy strong rfd winds with that storm. i got flat latter during that chase and watched as barn was ripped apart right next to me as the rfd moved in. that was approx. 7-8 miles se of mulvane at that time.

also of note with this storm was the crazy amount of damaging very large hail that fell over wichita with the hail core on this thing. the largest hailsone in kansas history fell on this day 7.75 inches in diameter!!!! HOLY NUTSNACK!!!!! anyone interested in severe weather will appreciate this link from ict nws! http://www.crh.noaa.gov/ict/scripts/viewstory.php?STORY_NUMBER=2010091902

once again thanks guys check out the link!

 

[Skip Talbot]

Although its possible its a tornado, this looks very much like outflow to me. A quick check for inflow/outflow features is, "Which way is it pointing?" Inflow features like wall clouds tail clouds point toward the rain, while outflow features like shelf clouds point away. You're looking northwest so these pointed clouds are pointing south/southeast, away from precip core/storm. The clouds here are being shaped by outflow. Its entirely possible to get a tornado on the gust front of an outflow dominant storm. However, in the absence of strong rotation, I'd say this is much more likely to be dust being kicked up by outflow. The cloud feature above the dust is probably what I've heard referred to as a "whale's tooth" Behind the gust front, looking straight up and to the east you see the "whale's mouth" These pointy lowerings on the leading edge are the "teeth." They are outflow driven features and, in the absence of strong rotation, are not funnels or tornadoes. There are similar, but smaller looking features to the left, which comprise the rest of the shelf cloud, and there is also dust to the left, although its less pronounced, which marks a long gust front.

 

[samuel stone]

Skip- your probably right, what you explain makes alot of sense. the question that arises to me is (if you take a look at the link i put up from ict nws) were these other tornadoes wich were confirmed with this storm(pics of them are on the link) do you think these were probably mostly just "outflow driven gustnadoes"? i will say that i was chasing this storm for its enitre duration of when those tornadoes were photographed and i did not notice these other ones. its probably hard to say without having seen it all your self but maybe those pics and radar images will help. THANKS SKIP

edit; the tornado reports to the SE of mulvane i would not have been in position to see at that time. as i was enduring 80 mph winds with a flat lol

 

[Skip Talbot]

Skip- your probably right, what you explain makes alot of sense. the question that arises to me is (if you take a look at the link i put up from ict nws) were these other tornadoes wich were confirmed with this storm(pics of them are on the link) do you think these were probably mostly just "outflow driven gustnadoes"?

Well, I wasn't there and without taking too much time to research this I can only make crude guesses based on these photos. Those pics by Jim Reed are interesting. That first shot looks like a nice little funnel. The others could be anything from outflow to gustnadoes to tornadoes. Its quite hard to judge from the photos alone. The key is identifying rotation that extends from the feature on the ground to the base of the storm. Storms that put down a large gust front like this one, produce A LOT of gustnadoes and outflow driven severe wind damage. An indicator of this is the radar image which shows a very large, fat, and bowing hook with a broad, but strong area of rotation aloft. There's probably a very powerful RFD associated with that supercell which is fanning out in broad arc along that bowing hook. Supercellular tornadoes are more than possible with a storm like that, but I'd expect a bunch of straight line wind damage and gustnado activity with that gust front.

Defining a tornado is not black and white. The line between tornado and not is fuzzy and grey since wind speeds, height, and tightness of rotation can vary across the spectrum. This storm reminds me of one I chased near Kinsley, KS on June 15, '09. The storm was very much outflow dominant and was kicking up a ton of dust, gustnadoes, and yet we counted a tornado. We initially dismissed the feature as a large gustnado/outflow, but there was indeed some (weak) rotation aloft in the form of a nub funnel and the circulation on the ground almost had a multivortex type nature to it:
http://skip.cc/chase/gallery/pages/090615ST01_jpg.htm
http://skip.cc/chase/gallery/pages/090615ST02_jpg.htm

That tornado was definitely in the gray area and there was some debate as to what it actually was. Collaborating with other chasers in the area we were able to come to a consensus that it probably was a weak tornado. That storm was kicking up a ton of dust and other interesting features though like this probable gustnado, behind the nice tail cloud above it:
http://skip.cc/chase/090615/09061508.jpg

More interestingly, the storm did go on to produce a large cone shaped supercellular tornado after we fell behind the core of the storm and thus we missed seeing it. When you fall behind large outflowy HP storms like this, a mile makes all the difference in the world between seeing the tornado and seeing only a precipitation core. While your storm may very well have produced large supercellular tornadoes, they can be easy to miss in these conditions even if you are quite close.

 

[samuel stone]

thanks for the insight skip, btw i loved looking through all your chases on your website