How does a tornado dissipate?

[crimsone]

So, I've just been considering some of the big F5 wedges in the last couple of decades, having been watching some youtube videos. We've all seen footage of a tornado touching down before it grows...

... but how do they typically dissipate? Presumably it's a boring process, as nobody ever shows it on video... but what's happening? Do they get separated from the main cell and just kind of peter out once the energy driving them isn't there anymore... do they thin again and rise back up into the clouds as a disappearing funnel? Or do they just sort of thin out like an evaporating windy mist?

Obviously I'm referring to the big ones here, but what causes them to finally give up, and how do they end?

[Marko1690]

Im no meteorological buff but i would say there's lack of the energy to feed it, whether it be heat, inflow wind etc 

[crimsone]

OK, so I just watched a recording of the KFOR live broadcast of the Moore (OK) tornado.

In that case, in no time at all it just went from a black dot on the doppler radar to a purple dot, within a cell that had hooked from the main storm and separated off. Just after the change in colour in doppler, it was heading into an area with nothing but trees and grass, and also a lake. The extensive debris cloud cleared, the wedge took on more of a barrel shape, the barrel got thinner and thinner, and it finally "roped out"... ie, turned into a twisting and turning rope-like vortex, which finally just dissipated as the tight circulation broke down despite the feeder bands still feeding, and the storm above stil rotating.

So now I know. I don't know if they all end this way, but it's an answer and I'm satisfied.

[Methuselah]

38 minutes ago, crimsone said:

OK, so I just watched a recording of the KFOR live broadcast of the Moore (OK) tornado.

In that case, in no time at all it just went from a black dot on the doppler radar to a purple dot, within a cell that had hooked from the main storm and separated off. Just after the change in colour in doppler, it was heading into an area with nothing but trees and grass, and also a lake. The extensive debris cloud cleared, the wedge took on more of a barrel shape, the barrel got thinner and thinner, and it finally "roped out"... ie, turned into a twisting and turning rope-like vortex, which finally just dissipated as the tight circulation broke down despite the feeder bands still feeding, and the storm above stil rotating.

So now I know. I don't know if they all end this way, but it's an answer and I'm satisfied.

I'll take a guess, Crimsone:

A tornado will dissipate once the energy due to atmospheric rotation is exceeded by the friction caused by the Earth's surface?? 

[Mokidugway]

Cold air outflow from ppn or downdraughts  to low level generally kills their unstable environment on which they thrive

[Freezeflake]

I believe when the RFD or forward flank down draft begins to cut the warm inflow off from the circulation. Same reason outflow dominant storms rarely produce tornadoes. happy to be corrected on this however 

 

[Jordan S]

On 4/9/2018 at 19:57, Freezeflake said:

I believe when the RFD or forward flank down draft begins to cut the warm inflow off from the circulation. Same reason outflow dominant storms rarely produce tornadoes. happy to be corrected on this however 

 

You are somewhat correct on this basically a tornado can dissipate for several reasons if any ingredient suddenly goes missing it will die.not just that but a tornado will always eventually die even with the ingredients because nothing can last forever it has a lifespan just like us humans.