the Vault

[Stephen Locke]

I made this grab with my computer. Storm Reports made this statement, "The storm also exhibits a hook echo near Selma and then wraps up into a complete circle shape, indicative of a bounded weak echo region. " Noaa Glossary says, "BWER - Bounded Weak Echo Region. (Also known as a vault.) Radar signature within a thunderstorm characterized by a local minimum in radar reflectivity at low levels which extends upward into, and is surrounded by, higher reflectivities aloft (Fig. 2). This feature is associated with a strong updraft and is almost always found in the inflow region of a thunderstorm. It cannot be seen visually."

Question; Why can't it be seen visually . . . doesn't it look like this?

Vault photo by Mike Hollingshead

 

[David Drummond]

That's exactly what it looks like.

You see it best on LP storms. Most Classic storms and almost never on HP storms.

 

[Stephen Locke]

Bounded Weak Echo Region (BWER)
(Also known as a vault.) Radar signature within a thunderstorm characterized by a local minimum in radar reflectivity at low levels which extends upward into, and is surrounded by, higher reflectivities aloft. This feature is associated with a strong updraft and is almost always found in the inflow region of a thunderstorm. It cannot be seen visually.

What is the meaning of the statement above in bold.?

 

[David Drummond]

BWER is something seen on radar that you would see in a cross section of the radar paint like this, not a single level scan: <clarified my wording there

I'm not entirely sure the visual "vault" and the radar "vault" they are talking about are the same thing. Maybe one of these schooled meteorologists around here can clarify.

The visual vault area like in Mike's pic, I can tell you many times is not as clear as it looks, and is often filled with huge hail.

 

[Greg Higgins]

I do believe that they are refering to the fact that you con not actually see the BWER if you were outside looking at the storm structure. It IS visual on radar (if you know what your looking for).

Greg Higgins

 

[Tyler Allison]

"can not been seen visually" means in person. If you were standing outside near the storm you could not tell if a storm had a BWER or not.

 

[Greg Stumpf]

I'm not entire sure the visual "vault" and the radar "vault" they are talking about are the same thing.

They are not the same thing. The radar vault is within the updraft of the storm - think about it. The updraft is suspending the precip particles. The "visual vault" (I term I don't like) is an optical illusion, and is in reality usually filled with precip - sometimes highly reflective (to radar) sparse large hail, thus it is visually translucent.

 

[Stephen Locke]

This is the report that raised the question for me. Is it correct that the radar vault should be visible on base reflectivity 1? If so, I'd like to see someone make a graphic that points to the vault area (on a base reflectivity 1 or similar) image.

 

[Dave Gallaher]

Thanks for posting that link--I clearly recall watching that storm on radar (and posting in the NOW thread) that I thought for certain it'd drop a tube. It's very fortunate it didn't, considering the route it took. Still, that was more like a TX/OK cell than what we usually get around here. I wonder if anyone got video or photos from in front of it?

 

[Stephen Locke]

That's a beautiful radar grab. I think this thread may have established that a radar vault and a visual vault are two different phenomena. Can someone take that image and define the radar vault area and the visual vault area?

 

[Chad Cowan]

This is the report that raised the question for me. Is it correct that the radar vault should be visible on base reflectivity 1? If so, I'd like to see someone make a graphic that points to the vault area (on a base reflectivity 1 or similar) image.

Here is a radar grab showing the reflectivity and velocity of the 1st (lowest) tilt and the 3rd (mid-level) tilt. Note the donut shape in the 3rd tilt, this is indicative of a BWER.

Here is what that type of storm looks like from the ground. This is looking due west into the supercell that just dropped an EF-4 near Blue Mound, KS on 2/28/07. On the left is the low-level meso and on the right is the forward flank core. The area between these two is commonly called the vault, even though it is a bit of a misnomer.

 

[Skip Talbot]

As David pointed out, the BWER is identified with a vertical slice of the radar. The region that is bounded is usually in the midlevels of the storm. Assuming you can see that part of the storm (low levels clouds/precip aren't in the way), you would just see the convective updraft tower where the BWER is right? Since the BWER represents the updraft of the storm, clouds should be condensing there. The BWER would look like a Cb tower if you could see it. Its going to be wrapped in portions of the tower that do have reflectivity though. So no, you can't visually identify the BWER from the ground because you can't see through the updraft tower like the radar can.

 

[Stephen Locke]

This was very helpful especially seeing the 1st and 3rd tilt simultaneously.
Thanks Chad.

-stephen