Thunderstorm size and tornado production

[calvinkaskey]

Is a larger thunderstorm more likely to produce a tornado due to more latent heat energy and or insulation from dry air?

 

[rdale]

It depends. Sometimes yes, sometimes no.

 

[James Gustina]

It depends on the overall environment. Its all about downdraft interactions and size is not necessarily a major factor so much as baroclinic vorticity generation in the downdraft (i.e. temperature and moisture content).

 

[Jeff Duda]

I don't think there is any correlation between the physical size of a thunderstorm and its frequency/likelihood of producing a tornado. As James alluded to, tornado production in a thunderstorm is much more dependent on sub-storm scale activities and features such as the generation of horizontal vorticity and a mechanism to tilt and stretch that into the vertical. Size has really nothing to do with a storm's ability to do that (to a point within scientific/physical reason, of course).

 

[calvinkaskey]

?

It seems like the most powerful tornadoes occur in large thunderstorms or are large tornadoes usually more powerful and larger tornadoes occur in larger thunderstorms?

 

[Kevin Rimcoski]

Still not necessarily right or wrong. Like said previously, it depends on the conditions. Why do some supercell thunderstorms produce tornadoes and others don't?

 

[James Gustina]

It seems like the most powerful tornadoes occur in large thunderstorms or are large tornadoes usually more powerful and larger tornadoes occur in larger thunderstorms?

Generally yes, but that's not always the case. There have been low-topped supercells two miles across that produce EF2+ tornadoes down south while an HP monster 9-10 miles across in SE CO near Lamar produced a small EF0.

 

[Wxradar12]

It always depends so yes and no. Sometimes thunderstorms are big like a squall line, but don't produce tornadoes. Sometimes they do produce tornadoes, it all depends on the storm and the right ingredients size doesn't really matter.

 

[John Olexa]

Still not necessarily right or wrong. Like said previously, it depends on the conditions. Why do some supercell thunderstorms produce tornadoes and others don't?

But when supercell's do it usually spawns the strongest tornadoes.

 

[Kevin Rimcoski]

But when supercell's do it usually spawns the strongest tornadoes.

No. You can have a monster of a supercell dropping grapefruits, 50k plus top and still no tornado, whereas you can have a 28k top like the recent outbreak in Louisiana and Mississippi that produced a few just based on wind shear

A supercell is just the strongest classification of a thunderstorm. But they do not always male tornadoes or the strongest. They can still drop very weak tornadoes but the storm is still a monster. The question is why

 

[Brian G]

Of some relevance is that updraft diameter seems to be an important part of a thunderstorm's evolution. I'm going through the book Mesoscale Convective Processes in the Atmosphere and Robert Trapp derives an entrainment rate formula from one form the vertical momentum equation. He comes up with E=C*1/R where E is entrainment, C is a constant, and R is the radius of the updraft. So environmental entrainment is inversely proportional to the size of the updraft. Big updraft = Little entrainment and vice-versa. I suppose that isn't surprising for those familiar with the "square cube law" as it would seem there could be a loose application there. Anyway, the text also seems to confirm that bigger updrafts help "insulate" the core from turbulent eddies that might otherwise act as a braking mechanism for updraft velocities. It is thought that the depth of the PBL plays a role in the updraft size. How this relates to tornado production rates...I don't know...but I did find it interesting!