Connecting Funnels/Tornadoes

Originally posted by Dave Kaplow
Why couldn't this be a single U-shaped vortex hanging beneath the cloudbase? The middle part between the funnels is the lowest, so maybe they're connected from the beginning but at first there's no condensation in the lower middle portion of the vortex. As the vortex intensifies, the condensation fills in, and the funnels appear to join up. Not suggesting this is necessarily what's going on, but it seems one possibility.

Alternatively, if you have 2 funnels hanging next to each other, and one is cyclonic and the other is anticyclonic, wouldn't the natural tendency be for the funnels to merge at their ends? I don't know enough about vortex dynamics to know if this is true or not, but I have a vague memory of reading somewhere precisely this explanation for the merging funnels.
Click to expand...

This theory sounds pretty good, and quite logical. I should have thought of something like this before...I mean it would make since, that they WERE connected to begin with, but just haden't rendered a condensation apprearance yet. Why do I here poeple saying 'Classic' video footage? Was this like a video out or something?
 
Originally posted by Andrew Khan+--><div class='quotetop'>QUOTE(Andrew Khan)</div>
<!--QuoteBegin-Dave Kaplow
Click to expand...
Why couldn't this be a single U-shaped vortex hanging beneath the cloudbase? The middle part between the funnels is the lowest, so maybe they're connected from the beginning but at first there's no condensation in the lower middle portion of the vortex. As the vortex intensifies, the condensation fills in, and the funnels appear to join up. Not suggesting this is necessarily what's going on, but it seems one possibility.

Alternatively, if you have 2 funnels hanging next to each other, and one is cyclonic and the other is anticyclonic, wouldn't the natural tendency be for the funnels to merge at their ends? I don't know enough about vortex dynamics to know if this is true or not, but I have a vague memory of reading somewhere precisely this explanation for the merging funnels.
Click to expand...

This theory sounds pretty good, and quite logical. I should have thought of something like this before...I mean it would make since, that they WERE connected to begin with, but just haden't rendered a condensation apprearance yet. Why do I here poeple saying 'Classic' video footage? Was this like a video out or something?[/b]
Click to expand...

They are referring to Tornado Video Classics... A trilogy documentary series by the Tornado Project: http://www.tornadoproject.com
 
Originally posted by Mike Hollingshead
Roger, do you recall if this storm was a prolific anvil crawler producer? I remember a storm in that direction around that time frame viewed from Blair. It was far enough away we couldn't really see much of it but what we were seeing was some super long crawlers flying overhead. I remember that and the very strong southerly winds. Interesting, I am wondering if this was that storm.
Click to expand...

Mike et al.,

No, I don't recall an unusual profusion of crawlers, but that doesn't mean there weren't some. Another supercell blew up shortly before sunset just W of that long-lived one, but quickly formed a deeply wrapped, "Figure-9" bears cage with arching rear-flank gust front. By about an hour after dark a few more cells had formed hither and yon, profusely sprinkling the area beneath the resulting MCS' anvil canopy with updrafts, cores and gust fronts. There was lots of LTGIC and in cores, but I don't recall anything extraodinary, crawler-wise.

Could the storm you remember be from the same date one year before, but farther S (near Central City)? I wasn't on it (evening shift), but Jim Leonard was...the 12 Jun 93 storm was briefly/weakly tornadic early then wound itself up into a very thick, brutish barber pole of an HP storm with numerous striations. It resembled a somewhat smaller and murkier Kress/Turkey appearance. From Jim's video there were tons of "zits" and crawlers spewing forth at some point just before total darkness.
 
Could the storm you remember be from the same date one year before, but farther S (near Central City)?
Click to expand...

Hmmm, no it wouldn't be that. I wish I had video and a date now, lol. That is really odd that I clearly remember it and even some of the people from town up on this hill watching it and yet I can't remember the year and surely nail it down. I could drive so I know it is after 92. Most of my storm video around town started in 95 as I can't recall having any storm video before that. I'm pretty certain it was between 93 and 95 and it was exactly where your storm was because West Point is probably 30 miles in a straight line due nw of Blair(where this was being seen...best guess). It was far enough away the only info you had it was there(other than these amazingly long crawlers) was the darkness way off. Also what makes it seem pretty 'special' was not just the length and frequency of these crawlers but the fact they were downstream of the updraft. It seems typically they are seen upstream. Then again maybe that isn't the 'norm'. I have always noted them while driving home behind an mcs, more so than inbound to intercept a storm to the west.

When I think back about very local storms that were memorable I've always had VERY few that came to mind. This area of extreme eastern NE has always sucked in my mind because of this. There was this one:

http://www.extremeinstability.com/june_20,..._supercells.htm (boy I should re-write old accounts). I believe the DOWs were on these. I wish I knew more about photography back then. That second supercell could still be the "best" supercell I've seen, hard to say.

When I think back about local stuff only that one and the one up towards West Point come to mind. That is how impressive the one seemed up that way back around the time of yours and in the same location. I couldn't even see structure, but the wind blowing into it and the crawlers coming from the one location, I just knew it was some amazing supercell up there. So I thought I'd try and find out if it indeed was yours shown here. I will say this display seemed to be happening just before sunset. The time would even match with your storm. Location and time seem to be spot on, lol. The lack of nice supercells in memory right around here really made me think these were the same storms.

Whatever it was, it was after 92 and before 95 and right there. Fun thinking about the storms. Btw, amazing supercell you caught there.

Edit:

Now that I think about it, if Jim's storm moved ne and was near West Point shortly before dark it very well could have been the same storm.
 
I apologize for resurrecting this old thread, but after searching the forum looks like this is adequate.

Yesterday in Catalonia, Spain, this phenomenon of two connecting funnels was recorded on video. Video only shows the phase when they seem connected but there were initially two different funnels:

http://www.youtube.com/watch?v=oQstlPTksnU
 
Wow. This is an old thread. I think the cyclonic and anti-cyclonic flow makes the most sense. I know that when the horiz. vorticity gets tilted into the updraft you get a cyclonic flow and an anticyclonic flow. In general, most supercells in north america have the cyclonic flow become dominant because of wind shear but this doesn't have to the be the case. For example:
updraft.png
which can look like this with condensation:
vort.jpg


If you expand the last picture out on a larger scale in a large scale updraft, i'm thinking that a downdraft in the middle of the vorticity circulations could push the circulation out of the cloud and make it visible. This would appear as if it was two funnels but in reality its one connected circulation the whole time.

Just a thought.
 
The video Mike Hollingshead mentions (shown in the YouTube link in the preceding post) is a great example of this phenomenon. I think what's happening in such cases is, what looks like two separate vortices are in fact just visible sections of a single vortex loop that arcs down from and then back up into the cloud base. Because the bottom part of the loop hasn't condensed, what you see are two separate funnels pointed toward each other. In the case of the Nebraska video, the bottom part of the loop fully condenses, so that the two funnels appear to connect and form a single unit. In reality, though, they were always a single unit, and the final filling in of condensation just made that fact apparent.

Notice that in these instances, the funnels are quite close to each other, suggesting that they are "Siamese twins," so to speak--conjoined, not individual entities.

ADDENDUM: I just noticed the date when this thread originated. It's way old. What I've written above applies to the kind of vortex originally cited, which extends downward from a cloud base, rather than to horseshoe vortices, which can appear in clear air. The two phenomena may be related, but they are distinct, and the former seems to be far more rare.
 
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Just wanted to thank all for this thread and to say its good to know that others are as intrigued by this as I am.

I saw the TVC "Nebraska" video years ago and thought that there must be something going on - more than just
a cyclonic / anticyclonic couplet.

The Vortex Ring idea seemed logical, and the idea that the lower portion - penetrating denser/warmer air - would be less visible
since there is less condensation - this seemed to make a great deal of sense to me. I have seen the same behavior in
the clear-air "horseshoe vortices" - the thicker parts seem to be the ones that are higher up - but its very hard to tell.

Vortex rings are very stable structures - did you ever see the video of the tiny smoke ring blowing out a candle
20 feet away ?

Glad to know others were thinking along the same lines - but this raises a question.

What is generating the ring vortex ???

The video from Spain seems to show a precip shaft penetrating the cloud
just behind and above the loop - is that part of the cause ??

The Nebraska video shows big hail just "behind" the vortex, but it is not clear
that there is any connection. Of course, hail would be expected in that part of the storm.

Any possible connection to microburst or RFD ??

Again, thanks to all for this great thread... (don't get me started on ball lightning - lol !!)

-T
 
Michael Thomas said:
What about this recent event in Canada-

http://www.stormtrack.org/forum/showthread.php?29196-2012-07-03-REPORTS-SK&p=324560#post324560

Looks like an interesting horizontal funnel there. It is a bit hard to clearly see what is going on in the video though.
Click to expand...

Yeah I noticed that too. Looks to me like the video shows a tornado and a bowtie funnel occurring simultaneously. Although it's hard to tell exactly what's going on from the video, it appears to me that the bowtie is a completely separate vortex from the tornado.
 
Dave Kaplow said:
Yeah I noticed that too. Looks to me like the video shows a tornado and a bowtie funnel occurring simultaneously. Although it's hard to tell exactly what's going on from the video, it appears to me that the bowtie is a completely separate vortex from the tornado.
Click to expand...

Yes the horizontal vortex was completely separate from the tornado. The storm had also produced several funnels before hand, some of which looked like they were 'orbiting' around each other. The tornado was also initially horizontal before tilting vertical.
 
sept2512a.jpg


Apologies for the necropost, but I wanted to post an example of one of these that I observed on Tuesday in Okawville, Illinois with by a supercell that would produce a tornado a couple of minutes later. I'm fairly positive this is a 'bowtie funnel' in which the anticyclonic side (on the left) briefly condensed back upward into the cloud base. The main tornado circulation was about a mile or so to the west of this feature. A video is here: http://www.youtube.com/watch?v=u81Jd42oNps
 
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