TVS/ETVS question

[Dean Baron]

I am wondering what the difference is between a TVS and an ETVS is? both signify strong rotation but whats the difference (or is there really a difference).

 

[mikegeukes]

Some Definitions: I found in some literature and online.

A Tornadic Vortex Signature, TVS, is defined as a TVS
3-D circulation with a base located on the 0.5°
slice or below 600 meters ARL (above radar level)

An Elevated Tornado Vortex Signature, ETVS, is defined as a 3-D
circulation with a base above the 0.5° slice and above 600 meters ARL

TVS - Tornadic Vortex Signature. Doppler radar signature in the radial velocity field indicating intense, concentrated rotation - more so than a mesocyclone. Like the mesocyclone, specific criteria involving strength, vertical depth, and time continuity must be met in order for a signature to become a TVS. Existence of a TVS strongly increases the probability of tornado occurrence, but does not guarantee it. A TVS is not a visually
observable feature.

Mike
http://stormchasingweather.blogspot.com

 

[Laura Duchesne]

It means Elevated Tornadic Vortex Signature. Basically when the radar is at its lowest tilt, the circulation is not as strong as on other tilts from higher parts up in the storm, but it can become a TVS.

Edit: Looks like Mike posted at the exact time as me, but his is much more detailed.

 

[rdale]

ETVS's are pretty much useless, most NWS offices have turned them off entirely.

 

[Dean Baron]

ah, i see. makes more sense now. thanks guys!