Vertical or Horizontal?

[John Hudson]

Seems one of the most common versions of mesocyclone formation and tornadogenesis has to do with horizontal wind shear - the "tube" forming in front of the advancing air mass that starts spinning, then gets drawn upright into the thunderstorm's updraft.

Isn't rotation in a mesocyclone just as likely to evolve from vertical shear, also? Or, is it possible that the jury's still out on which scenario is more common?

 

[Glen Romine]

John,

There is good consensus among meteorologists that the mesocyclone rotation is derived from the vertical wind shear, for tornadoes, far less is known. 0-3 km sreh is a good measure of the magnitude of vertical wind shear a storm might ingest (provided the background is favorable for organized storms). This rotation at midlevels is only somewhat associated with the rotation at ground level necessary for tornadoes. Certainly vertical wind shear alone can't get a vertically oriented rotating air mass at the ground. So, horizontal wind shear near the ground is the most plausible candidate, and there are a number of possible sources for that both internally and externally from the storm. As for why 0-1 km sreh is strongly correlated with tornado events, but not so much 0-3 km sreh (and both are measures of vertical wind shear), I think the easiest conceptual model to believe is that the lower the strong vertical shear, the lower the base of the mid-level mesocyclone.

An analogy might be to imagine having a large magnet, and iron filings like you probably used in a high school science class. If you want to pick up the filings, you could get the magnet closer to the filings, or the filings closer to the magnet. Pretend the magnet is the mesocyclone, and the filings are the horizontal wind shear at the surface. if you have lots of low-level horizontal wind shear at the surface, you can 'pile up' lots of the filings to reach closer to the magnet, and *if* the magnet is overhead at the right time and place, it will pick up the filings if it is close enough. Stronger magnets reach the filings from further away, or magnets moved closer to the filings could also potentially get the job done.

Glen

 

[Andrew Khan]

Most commonly what I have seen is, generally the horizontal spinning tube, like vortex, that is later brought into a vertical position in the atmosphere, due to the thunderstorms intense updraft. Isn’t this the only way mesocyclones can form, that was the illusion that I was under. Also, I figured that once the tube was turned vertical it immediately produced a tornado, as the tube became vertical a TVS became evident immediately.

 

[Brian Stertz]

I think chasers see different things dealing with tornadogenesis with each tornado...one trend I am becoming more and more convinced that it's necessary to have a good cascading warm and humid RFD (in most cases). I have seen so many updrafts look mean as hell..and pull everything but the barbed wire fence up into the rotating bowl and still no tornado. The missing element was the RFD...seen this time and time again. The RFD gives it that kick start to get things staying intact, focused, and strongly rotating.

 

[Andrew Pritchard]

Most commonly what I have seen is, generally the horizontal spinning tube, like vortex, that is later brought into a vertical position in the atmosphere, due to the thunderstorms intense updraft. Isn’t this the only way mesocyclones can form, that was the illusion that I was under. Also, I figured that once the tube was turned vertical it immediately produced a tornado, as the tube became vertical a TVS became evident immediately.

You mean.. like the pretty computer graphics we see on the television shows with the awesome life like arrows?

Personally.. I think the horizonizationalization of the verticalized parcel of the rotating vertical airmass contributes more to the lightning of the vaccuum and tornadoes.

 

[nickgrillo]

Well....

Most commonly what I have seen is, generally the horizontal spinning tube, like vortex, that is later brought into a vertical position in the atmosphere, due to the thunderstorms intense updraft. Isn’t this the only way mesocyclones can form, that was the illusion that I was under. Also, I figured that once the tube was turned vertical it immediately produced a tornado, as the tube became vertical a TVS became evident immediately.

You mean.. like the pretty computer graphics we see on the television shows with the awesome life like arrows?

Personally.. I think the horizonizationalization of the verticalized parcel of the rotating vertical airmass contributes more to the lightning of the vaccuum and tornadoes.

Nope... The horizonizationalization of the verticalized parcel rotation is actually for an undiluted column. You have to assume the vaccuum of the atmosphere is stronger than the ambient growth of a periphal air parcel of vorticity. For this, we use this:

<img src=http://ulcar.uml.edu/~iag/CS/FN-equation-GF.gif>

and plug it into the simple ascending invisible updraft code (Beavis and Butthead, 1995, hereafter BB95):


WI = 5[HMRQ(Γ2 − 30 + QL − 2QM)]0.5 = Ascending Invisible Updrafts

But, if we assume the vortex parcel is well approximated by the ageostrophic response of BuRp, then we'll use the following method to calculate super vorticity, which is considered the super-visualized Flux Capacitor in the A-Deloreon, where

<img src=http://astron.berkeley.edu/~jrg/ay202/img1803.gif>

is considered the point of traveling back to A-1955 and retrieving scopes of 89-M undiluted CPL and the Gigawat Budget. However, you should be VERY careful when using the Gigawat Budget equation... You will need to calculate nucleated agglomerative and lift the virtual TP and assume it equals the π/2 of,

<img src=http://astron.berkeley.edu/~jrg/ay202/img1787.gif>

Which when BB95 was trying to explain,

the area PQR is also formed by removing area updraft ascent from PT-inconsiderable mass equation for a TaCOO Bell

PQR = PCR - QCR

In which PQR is the equation of thermals, PCR is the equation of rotating vorticity in a bowl and QCR is the mass momentum of a flush, which we plug into the equation BB95 gave us, and we recieve = Mass Ascent of Vorticity stretched by a COLUMN of warm, moist vorticity.

I hope this clears ya'll up....

:lol:

 

[Tim Johnson]

Your problem isn't well defined. You must have implicitly assumed F_0 = 0 and F_1 = 1. Otherwise, F_1 = F_0 = 0. F_k = F_k-1 + F_k-2 is fine as defined, however for k > 1 (that is, if your series converges). Anyway, properly defined, this means F_k represents the Fibonacci sequence.

Yeah, I was going to point that out also, but Chris beat me to it...lol :lol: