Vault, Vault area?

[Glen Romine]

You sat under the vault. To be in the vault, you would need to be aloft, with precip surrounding you on all sides and on top.

I think most people think of the vault as the weak echo region - not the BOUNDED weak echo region, which is the 'official' AMS certified definition of a vault. Still, a BWER could extend to the ground, we just don't typically have the ability to sample it. Airborne and mobile radar observations have gotten pretty close, and seems reasonable there can be short transient times in some storms when there is precip wrapping completely around a portion of the updraft. Clearly there is no way to tell from the photo if he was in the vault or not - but visually it does show what is likely a weak echo region from the left edge of the wall cloud over to the main precip core on the right. If folks want to call that area the vault - I don't see how this negatively impacts the community. Apparently Roger Edwards agrees as well based on the previous link in the thread, so maybe there could be some looser interpretation.

 

[Greg Stumpf]

I guess it's probably enough to know what it visually looks like and that it might not be precip clear(but still called the vault by chasers). Is there some name chasers use for when it's not completely free of precip, but appears so? I bet it's "vault"....but probably should be "visual vault". But I'm sure that's not acceptable enough.

The orignal poster asked about the "vault". You pointed out something in your picture that is technically not a "vault" as defined by radar. As for a "visual vault", I have never heard that term used before in chaser parlance. Rather than not confuse the original poster, and make up "new" chaser terms, why not use the commonly accepted term for "vault" as I have done?

You can find the official definition here (with images):

http://www.srh.noaa.gov/oun/severwx/glossary.php#BWER

 

[cdcollura]

Good day all,

First of all, I cannot even describe any of Hollingshead's supercell photo work as anything but awesome!

Anyway, the true vault region is basically precip (or almost) precip-free. It bounds the "surface" of the updraft tower and hail / precip falling from the forward flank of the storm.

In Hollingshead's photo, the arrow is actually pointing to the edge of the (huge) hail shaft just right of the vault, if you were to be really nitty-gritty on where the precip-free (or least precip) area is in the vault.

On radar, the vault appears as a weaker (or nothing) echo "notch" extending from the east into a supercell (N Hemisphere with a cyclonically rotating storm). This is called a BWER, or bounded-weak echo region.

This area can be (visually) clear upwards of 20,000 or 30,000 feet AGL, providing a spectacular view of the updraft forming a "vaulted ceiling / cathederal" type appearance. This is common with LP supercells, less with Classic, and often hidden by precip in HP storms. Many times, the vault is not visually discernable (weaker supercells with weak BWER on radar).

Only in extreme cases, like LP / Classic storms do we actually see the BWER as a vault!

Above is a picture of an LP supercell in Colorado in May 2005. The view is WSW, with NW flow aloft, so the vault is more on the NW side of the storm than the N side. The vault is in the exact center of the picture. Right of the vault, you barely see anything, even though large hail may be falling.

Above is another vault in Colorado in June 2005. This one was loaded with large hail, so it was not exactly "precip-free". Note the narrow area between the updraft tower (left) and the baseball hail shaft (right) with twilight peeking through!

The view is due west. This storm produced a tornado 5 minutes after this picture was taken (from the lower cloud feature to the lower-left in this picture).

Hail does not attenuate light as much as rain does, however, if you were unlucky enough to be right under the vault, the hail will attenuate you and / or your vehicle!

One final "vault shot", looking more NNW than WNW into this cyclic supercell's vault (note the "stair step") of the June 12, 2005 Kent County (near Spur) storm in TX that produced nearly a dozen tornadoes. A 1/2 mile wide tornado was in progress when this picture was taken (see below)...

No, this is not considered a "vault" as some may call it (as the "RFD vault") to the left of the tornado. The clear RFD has wrapped all around the meso (and wedge tornado under it) and cleared any clouds blocking its view. This eroded clear slot allowed a view from the tornadoes base and "barber-pole" meso above it to about 30,000 feet.

 

[Robert Dewey]

Actually, the OP said "vault area" which could mean a certain perimeter around the actual vault itself. If there is hail falling anywhere within that certain "perimeter", then Hollinshead would also be correct. Now, it's up to the OP to decide such a perimeter (it's ambiguous right now), but I think Hollingshead's photo pretty much answered the question.

Sorry, I find semantics to be pretty funny.

 

[David Drummond]

One final "vault shot", looking more NNW than WNW into this cyclic supercell's vault (note the "stair step") of the June 12, 2005 Crosbyton storm in TX that produced nearly a dozen tornadoes. A 1/2 mile wide tornado was in progress when this picture was taken (see below)

No, this is not considered a "vault" as some may call it to the left of the tornado. The clear RFD has wrapped all around the meso (and wedge tornado under it) and cleared any clouds blocking its view. This eroded clear slot allowed a view from the tornadoes base and barber pole meso above it to about 30,000 feet.

A little correction Chris, that storm happened in Kent County, an entire county and a good 60 miles south of Crosbyton.

 

[Brian Emfinger]

As for a "visual vault", I have never heard that term used before in chaser parlance. Rather than not confuse the original poster, and make up "new" chaser terms, why not use the commonly accepted term for "vault" as I have done?

You can find the official definition here (with images):

http://www.srh.noaa.gov/oun/severwx/glossary.php#BWER

Roger Edwards seems to know the phrase "visaul vault" (as previously linked):


http://www.stormeyes.org/tornado/SkyPix/dayvault.htm

 

[cdcollura]

Good day,

A little correction Chris, that storm happened in Kent County, an entire county and a good 60 miles south of Crosbyton.

Yeah that was some supercell - Just corrected the county on it. I was not sure of the county but I know it was not far from Spur / Jayton.

Thanks...

 

[Greg Stumpf]

Roger Edwards seems to know the phrase "visual vault" (as previously linked):

http://www.stormeyes.org/tornado/SkyPix/dayvault.htm

I didn't catch that link the first time - it was at the bottom of the post, and appeared to be part of the .sig. So, yes, another chaser has used that term.

I'm fairly certain that Roger is using that picture as an extreme example of how we might visualize an echo-free vault - as defined by radar. But if there is precip falling into it, especially large hail stone, a vault it is not. The vault (BWER) is caused by the updraft, air rushing upward pushing precip out of the way (or precip not having yet condensed). Much of the echo free region is actually within the boundaries of the updraft cloud (probably straddles the cloud and cloud-free areas).

I would certainly not tell folks that they are "in a vault" when their windsheilds are being pummelled by grapefruits!

 

[Brian Emfinger]

I dont think there will be many times where the BWER/Vault area is completely echo free... which is probably why its called BWER (Bounded Weak Echo Region) not BNER (Bounded NO echo region).

 

[Jeff Snyder]

I dont think there will be many times where the BWER/Vault area is completely echo free... which is probably why its called BWER (Bounded Weak Echo Region) not BNER (Bounded NO echo region).

Many supercells have true, completely echo-free vaults. However, the "echo-free" is also colocated with cloud water in the updraft, so you just can't "see" the echo-free area. If we go off the visual definition of the vault (which I think many, if not most, chasers use), then I agree with you -- many of the visually transparent areas between the front-flank precipitation and the updraft (the area many would call the vault, which I'll call the "visual vault", and that area shown in photos throughout this thread) aren't likely to be entirely echo-free. This would be particularly true in the lower portions of the updraft, where there isn't much in the way of echo overhang sometimes.

Of course, we could beat this radar definition further, since what's "echo free" on a standard S-band 88D may not be echo free on an X-band or W-band radar. So, your mileage may vary, since the presence or absence of "detectable echo" depends on the sensitivity of the radar, radar wavelength/frequency, and other factors.