Wall cloud?

[Tyler Burg]

this is a wall cloud right? I think it is very hard to tell, thanks in advance.

 

[Brandon Sullivan]

Hmm.. Little hard to tell.. The 2nd image makes me think so. I am sure no expert either, which is why I am part of this group too.. lol.

it does like like it wants to have some inflow in the 2nd picture, which is why I am leaning toward a yes.. It is hard to tell with all the cloud cover however where it is relative to base/updraft of the storm...

I would say yes, but not the most defined thing however.. Nice catch though inside the cloud cover..

 

[Mike Peregrine]

It is a little difficult from these photos - the last one makes me think it possibly is. Usually they catch your eye for several reasons ... they form close to the intersection between updraft (rain free base) and downdraft. They are usually an abrupt and noticeable lowering in the cloud base. Wall clouds are attached to the cloud base and are persistent. Many wall clouds appear like a wedge-shaped block. They sort of slant down at an angle toward the downdraft. As they mark an area of strong updraft, visible condensate will often form in this triangular type shape as some of the rain cooled air in front of the wall cloud gets pulled up into the base of the storm. They look decidedly different from other types of lowerings in the cloud base, such as shelf clouds, etc.

Because of the angle we are looking at your photos, it is difficult to judge where the downdraft and RFB regions are located in this storm. But if you look at your prospective wall cloud here - up at the top, where it meets the rest of the cloud base on the right, you can make out a familiar little rounded notch that we often see on wall clouds. This makes it appear to me that this is possibly an area of rotation.

 

[Bill Hark]

It's difficult to determine from your pictures. From the last picture, "maybe".

I took the following description from the NWS glossary.

A localized, persistent, often abrupt lowering from a rain-free base. Wall clouds can range from a fraction of a mile up to nearly five miles in diameter, and normally are found on the south or southwest (inflow) side of the thunderstorm. When seen from within several miles, many wall clouds exhibit rapid upward motion and cyclonic rotation.

However, not all wall clouds rotate. Rotating wall clouds usually develop before strong or violent tornadoes, by anywhere from a few minutes up to nearly an hour. Wall clouds should be monitored visually for signs of persistent, sustained rotation and/or rapid vertical motion.

Over the years, I have found wall clouds to be fairly common on thunderstorms. The most important thing about wall clouds is the presence of rotation. A rotating wall cloud is important for chasing and for storm spotting.

Bill Hark

 

[Terry Tyler]

i dont know about that one, tough to be sure...things that support it being a wall is on the last two pictures...the cloud appears to be firmly attached to the rain-free base and it does have that "solid" look, which is good...and also like its trying to pull some inflow, it does also have some other visual clues that make it look like the real thing...

one thing that stands out to me though, if its not a wall is that alot of the other clouds are similar to that cloud and you really cant see any mid-level storm features to show how high the storm is...sometimes some heavy cumulus in dark light conditions can look ominous...also, i cant clearly define a downdraft in those photos...

if it was a wall cloud it would probably be something from some low-topped storm that just had some decent looking low-level structure...the most important questions though to help us find out for sure would be to tell us if you were under a warning, and what time, date and location these photos were taken for us to go back to the records and see whats up...

 

[Brian Stertz]

Looks to me like this is an updraft base forming, but would not say wallcloud because of the absence of a well developed core in its vicinity. Unless there was strong shear aloft to carry away the rain/hail away from the updraft area...I would say that this series of pics probably does not supply enough info to say this was a wall cloud.

 

[BKDPhillips]

6/3 KC Area wall clouds?

Hello,

I also have several pics (though of poor quality due to being taken on a modern day "instamatic" a Sony Cybershot) that I took on a impromptu yet very exciting adventure on June 3 in Johnson County Kansas then into Lees Summit, MO. I am confused as to what is a wall cloud and what is not (primarily because I see so many clouds called wall clouds in various pics/videos that I in my opinion would not have thought were wall clouds).

Please let me know which ones below are or are not wall clouds or funnels in your opinions from these poor pics of limited views. The times and some places are approximate because I was driving, shooting, and trying to tell a friend how to check radar on her laptop and having a fantastic time!

Looking West northwest from Blackbob Road in Olathe around 6pm

Looking West north west from either south of I435 on Holmes or Hwy 71 around 6:35pm (reported funnel/wall cloud but I couldn't see due to trees) I think, the part obstructed by the trees right 1/3 of pic.

Looking North while driving east on I435 or I470 around 6:45pm

Looking west in Lees Summit around 7pm reported wall cloud over Longview Lake which is approximately 4 mi west of our location - would this be it?

Not a wall cloud just thought I'd share since it was pretty as I drove home- looking north from 139th and Blackbob in Olathe around 8pm before the next storms arrived!

Thanks for your comments and to Eric F (and others) for his encouragement to post these pics. I have so much to learn!

Belinda

Mods: This is my first time to try and post pics.... please let me know if I did not follow the rules correctly because I am relatively new to using forums and posting pics compared to most people, thanks!

 

[Darrin Rasberry]

A rotating wall cloud is important for chasing and for storm spotting.

Bill Hark

With all the HP madness, I've been fooled quite a bit. Mostly, it's from lowerings on the leading edge of HP (not the shelf itself of course, but typically behind it) that appear to collect scud, and, when closer, display motion. One I saw a few days ago at the edge of Ames caught my eye for more than a moment, but I noticed after a while that its motion was vertical, and not in a gyre. From further away, it can be very hard to tell.

Many interesting "features" have also come (speaking of HPs) on the edge of whale's mouth-ish overhang. One of these on a different spot on the Parkersburg storm had a cheese-shape to it, as well as rotation and what appeared to be a clear slot - all, however, hanging off a cloud that appeared to be more of the aforementioned whale's mouth. I assumed with all the turbulence that day that it was indeed a wall cloud, but that it was too elevated to be any danger, but nonetheless it was warned and it cleared out a nearby town.

What makes me question the validity of my initial assessment, though, was a chaser video of this object taken at a different angle. From their POV, it was definitely IMO a wall with rotation hanging off of a good, solid base. From my POV it was as described. I'd estimate we were two or three miles to the south of its east-moving path, while the chasers were two to three miles north of its path. I wish I had bookmarked the footage to show you, and that I could figure out how to manage my programs and lift my own footage of it from my angle as well, but you'll have to give me the benefit of the doubt here.

Short version: how can you tell wall clouds from scud-collecting, vertically-moving, behind-the-shelf features on HP storms which are not yet entirely outflow-dom?

 

[mike scantlin]

all i can say is that every storm is different and no 2 storms are exactly alike. there can be many different areas of rotations, or just one solid area. it can look like crap, and produce tornadoes, or look like a wedge-producer, and not even touchdown.

the definition of a wall cloud is a lowered area of condensation with rapid upward motion, and persistent rotation. PERSISTENT rotation. i think the term "wall cloud" is waaaaay over-used(i know i'm guilty) and the more appropriate term would be "lowering" or "appendage" for one of these not wall cloud wall clouds.

 

[Bobby Prentice]

this is a wall cloud right? I think it is very hard to tell, thanks in advance.

Here are two definitions of "wall cloud."

wall cloud—(Sometimes referred to as pedestal cloud.) A local, often abrupt lowering from a cumulonimbus cloud base into a low-hanging accessory cloud, normally a kilometer or more in diameter.
A wall cloud marks the lower portion of a very strong updraft, usually associated with a supercell or severe multicell storm. It typically develops near the precipitation region of the cumulonimbus. Wall clouds that exhibit significant rotation and vertical motions often precede tornado formation by a few minutes to an hour.
Fujita, T., 1959: A detailed analysis of the Fargo tornadoes of June 20, 1957. U.S. Wea. Bur. Res. Paper 42, p. 15.

*Wall Cloud - A localized, persistent, often abrupt lowering from a rain-free base. Wall clouds can range from a fraction of a mile up to nearly five miles in diameter, and normally are found on the south or southwest (inflow) side of the thunderstorm. When seen from within several miles, many wall clouds exhibit rapid upward motion and cyclonic rotation. However, not all wall clouds rotate. Rotating wall clouds usually develop before strong or violent tornadoes, by anywhere from a few minutes up to nearly an hour. Wall clouds should be monitored visually for signs of persistent, sustained rotation and/or rapid vertical motion. See Fig. 7, supercell.

"Wall cloud" also is used occasionally in tropical meteorology to describe the inner cloud wall surrounding the eye of a tropical cyclone, but the proper term for this feature is eyewall.

I prefer the latter definition since I believe a wall cloud need not be associated with a supercell or organized multicell thunderstorm. Thus, the three pictures in question certainly appear to be wall clouds to me.

 

[Gene Moore]

Here are two definitions of "wall cloud."

I'd like to bounce off Bobby's two good examples with a few comments. If you buy the strict definition of either one there is a good chance you'll be missing important information. Many of these storm structure definitions came from the original chasers in the 70's and now they are dated. For example, "a wall cloud originates from a rain free base." Think about that for a bit, why does an updraft/wall cloud have to be rain free? This goes back to the old concept that updrafts (especially strong ones) hold precip and hail aloft, thus rain free. Rain is a downdraft event thus less likely to develop a wall cloud or tornado, again old thinking. Wall clouds, updrafts and tornadoes can and do form in the rain and can sustain for a long period of time.

As Mike points out and I agree, the term is overused. In a severe or tornadic situation every blocky lowering is a wall cloud. I don't think Fujita, who coined the term meant it to be used in that manor. Wall cloud was directly associated with tornadoes in his early writings. In later years the current wall cloud definition was loosened to teach spotters that a wall cloud was a precursor to a tornado. Well sometimes it is, sometimes not. Fact is a wall cloud associated with an RFD notch is certainly a better precursor to a tornado than some random blocky lowering. For example, in the colder air behind the gust front we often see very large block lowerings associated with updrafts that never produce tornadoes. When we use these terms to help us find tornadoes or predict their incipient formation we need to apply the whole package. That is, not single out or isolate one feature without looking at what surrounds it, or what might be causing it....if that makes sense.

Finally, it helps to remember that a wall cloud is more than likely caused by a localized reduction in temperature as cool (near saturation) outflow air mixes with warm inflow air under an updraft. This combination lowers the cloud base LCL at or near the updraft. It's also why a true wall cloud is often lower on the side closest to the precip, commonly the north side, but not always.

As for the images posted, some are certainly wall clouds, some are suspect. One thing that helps sort out this dilemma is to watch tropical storms in a non-jet stream environment. Non-rotating wall clouds or wall cloud looking features are very common because of the high moisture and low cloud bases, yet most do not produce rotation much less tornadoes.

 

[Eric Flescher]

awesome write up Gene about wallclouds

Many years ago when I first heard about wallclouds, their genesis seemed very confusing as to their creation/appearance from the rest of the cell. Your provided information Gene is very well done indeed.

Below two pics

I have one of my favorite pics of 6/3/08 Overland Park , KS looking west over I-35 from 95 street. I like that little downwards projection from what looks like a wallcloud (I could not tell from the video whether there was actual rotation as this storms was moving south (left).

Also zooming out , there were two other like projections. The one on the left looks like a wallcloud or a wanabee?
One looks definitely like a tail cloud but the one on the right not sure
what do you all think?
::

I'd like to bounce off Bobby's two good examples with a few comments. If you buy the strict definition of either one there is a good chance you'll be missing important information. Many of these storm structure definitions came from the original chasers in the 70's and now they are dated. For example, "a wall cloud originates from a rain free base." Think about that for a bit, why does an updraft/wall cloud have to be rain free? This goes back to the old concept that updrafts (especially strong ones) hold precip and hail aloft, thus rain free. Rain is a downdraft event thus less likely to develop a wall cloud or tornado, again old thinking. Wall clouds, updrafts and tornadoes can and do form in the rain and can sustain for a long period of time.

As Mike points out and I agree, the term is overused. In a severe or tornadic situation every blocky lowering is a wall cloud. I don't think Fujita, who coined the term meant it to be used in that manor. Wall cloud was directly associated with tornadoes in his early writings. In later years the current wall cloud definition was loosened to teach spotters that a wall cloud was a precursor to a tornado. Well sometimes it is, sometimes not. Fact is a wall cloud associated with an RFD notch is certainly a better precursor to a tornado than some random blocky lowering. For example, in the colder air behind the gust front we often see very large block lowerings associated with updrafts that never produce tornadoes. When we use these terms to help us find tornadoes or predict their incipient formation we need to apply the whole package. That is, not single out or isolate one feature without looking at what surrounds it, or what might be causing it....if that makes sense.

Finally, it helps to remember that a wall cloud is more than likely caused by a localized reduction in temperature as cool (near saturation) outflow air mixes with warm inflow air under an updraft. This combination lowers the cloud base LCL at or near the updraft. It's also why a true wall cloud is often lower on the side closest to the precip, commonly the north side, but not always.

As for the images posted, some are certainly wall clouds, some are suspect. One thing that helps sort out this dilemma is to watch tropical storms in a non-jet stream environment. Non-rotating wall clouds or wall cloud looking features are very common because of the high moisture and low cloud bases, yet most do not produce rotation much less tornadoes.

 

[Gene Moore]

Hi Eric, the first image certainly looks like a wall cloud, I can't tell with the second. The size of the images came out very small on my monitor keeping me from seeing much detail. If possible it's better to capture the storm structure around the suspect wall cloud in order to get a clear picture of what else is going on. Storms with multiple flanks can be the most difficult to sort out.

If the base of the storm is very low there is a reasonable chance there will be no wall cloud. A wall cloud is not a requirement for a tornado to form. That is, the tornado will likely come out of a low "sagging" base. This is more common in areas where the temperature/ dew point are close as the storm goes into tornadogenesis. It's also seen during outbreaks east of the Mississippi where not all of the classic supercell structures are evident.

On the other hand the most dramatic wall clouds are likely when there is a high LCL or sometimes called CCL. Where the ascending parcel must rise all the way to the environmental temperature before a cloud forms. This is most common in the high plains of eastern Colorado or western Nebraska during the late season. In those situations the difference from the original cloud base and the base of the wall cloud my differ by 5,000 feet.

On board radar, especially level II products are good for determining if our wall cloud is associated with a circulation aloft.

 

[Tyler Burg]

so the first one, Im not convinced its a wall cloud, though, I took a time lapse with the camera with a frame every few seconds, and there was quite a bit of inflow...problem is with me, is that I saw many "lowered clouds with inflow" this summer, mainly being in a stationary location, only got to go out a few times. So I dont beleive its possible for one area to see so many storms like this, either that or this was one crazy summer here. probably saw 5-6 storms with lowers and inflow.

the second one, that rain shaft, started that small and grew huge! what is happening there?

thanks in advance guys.

Tyler