Odd sighting.

[Bryce Stone]

Okay, can anyone help me with this? This picture is from last Tuesday (what, the ninth?). It was taken about two miles west of Stringtown, OK on Highway 3, looking back to the SE. I noticed this feature, and wondered if it might be light coming from inside the mesocyclone. As you can see in the picture, the sky was dark everywhere except for the center of whatever feature this was. Any thoughts? Is it possible for there to be a hollow center in a storm where light comes down from higher elevations? Thanks in advance for any replies.

 

[Jeff Snyder]

Okay, can anyone help me with this? This picture is from last Tuesday (what, the ninth?). It was taken about two miles west of Stringtown, OK on Highway 3, looking back to the SE. I noticed this feature, and wondered if it might be light coming from inside the mesocyclone. As you can see in the picture, the sky was dark everywhere except for the center of whatever feature this was. Any thoughts? Is it possible for there to be a hollow center in a storm where light comes down from higher elevations? Thanks in advance for any replies.
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What time was it taken? I was on the same storm, and we saw a ton of intracloud and anvil-crawling lightning with that storm. As we were driving back to Ada (and eventually OUN), it was quite an impressive site at times. I just wish I hadn't had a lot of stuff to get done the next day (e.g. 8am final exam), as I would have liked to have stopped for 20-30 minutes for some lightning photos.

If it was after sunset, I'd guess it'd be lightning. The 'feature' resembles an RFD clear slot and possible wallcloud, but that's very difficult to ascertain without knowing exactly what part of the storm you were in. Looking at radar at like 8:30, I remember seeing at least one decent area of rotation from TLX, but that was heavily embedded in a 50-60dbz core. Regardless, I believe the covnection down there had firmly transitioned to MCS, so that would essentially eliminate the RFD possiblity. I know when we drove to from the convection west of McAlester to the Coal / Atoka co storm, it was looking like it was gusting out (looked likes the typical 'wales mouth' / underside, backside of a shelf cloud), so it may have just been some random cloud formation of little consequence.

 

[Bryce Stone]

It definately wasn't lightning. The light was persistent (lasted about two minutes). I took one other pic, but it didn't come out well at all. I honestly have no idea what time it was, but I know it wasn't dark yet. I'd say maybe about 45 minutes before sunset (?). I felt fairly confident at the time that it was a wall cloud, but I can't say so with 100% certainty. There was incredibly rapid scud motion all around the area I was, but there was no organized rotation. I've seen plenty of wall clouds, but never one with light coming out of it.

 

[Brian Stertz]

That looks like the RFD "donut hole" as the supercell was collapsing. I was talking with Jeff Piotrowski at the time, and he said that was what he was watching happen. The brightness is the sun shining on the big updraft tower as it looks to me.

 

[Bryce Stone]

That looks like the RFD "donut hole" as the supercell was collapsing. I was talking with Jeff Piotrowski at the time, and he said that was what he was watching happen. The brightness is the sun shining on the big updraft tower as it looks to me.
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That's kind of what I figured it was. So I assume that means that there is a relatively cloud-free column in the center of a supercell which extends up far enough to channel light downwards? I guess I'm kinda fuzzy on exactly what processes allowed this light to extend downwards from (presumably) the top of the cell to the ground. Could it be similar to the eye of a hurricane? I know in a couple of first-person reports I have read, observers looking up into a funnel have reported being able to see very far up.

So anyway, when I saw this light in a place where there should not be light I immediately thought of those stories and wondered if that was what was happening. Obviously there was no funnel here, but am I correct in what I think happened? If so, why have I never seen this phenomonon before? Like I said, I've seen literally hundreds of wall clouds and associated cloud features, but have never seen something like this before. I guess the pic doesn't quite do the thing justice. It was really neat in person.

 

[Stan Rose]

That's kind of what I figured it was. So I assume that means that there is a relatively cloud-free column in the center of a supercell which extends up far enough to channel light downwards? I guess I'm kinda fuzzy on exactly what processes allowed this light to extend downwards from (presumably) the top of the cell to the ground. Could it be similar to the eye of a hurricane? I know in a couple of first-person reports I have read, observers looking up into a funnel have reported being able to see very far up.

So anyway, when I saw this light in a place where there should not be light I immediately thought of those stories and wondered if that was what was happening. Obviously there was no funnel here, but am I correct in what I think happened? If so, why have I never seen this phenomonon before? Like I said, I've seen literally hundreds of wall clouds and associated cloud features, but have never seen something like this before. I guess the pic doesn't quite do the thing justice. It was really neat in person.
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Bryce: impossible to say exactly what the pic represents. If you had your precise location and a corresponding set of all the radar tilts at that time, that might be a start! Sounds like you're thinking of BWERs (bounded weak echo region) that can result from a strong updraft, but if i had to guess id go with something like the rfd explanation already offered. Just remember that the storm probably isnt vertical, it's tilted so dont assume that light is extending from the "top" to the ground. It was probably extending from a very peripheral "side" to the ground, even if it seemed like you were near the "center" of the storm.

 

[Mike Hollingshead]

Odd, I figure such lighting is at least as common as real wall clouds. That happens often unless you have a massive anvil sheild.

Wait till you see it like that but have it extremely violet or pink and covering a much larger area.

 

[Jeff Snyder]

BWERs are radar features that indicate that intense upward motion is prohibiting the development of larger raindrops and hailstones (and the larger drops and stones are being lofted away from that area). That said, BWERs are not areas where the air is subsaturated (actually, it can be quite supersaturated), so it's not the case that the area is "cloud-free" (e.g. there's not a cloud-free area in the center of the updraft). RFDs are often found on the very backside of the updraft (and, actually, it's a downdraft by definition, so it's isn't found in the updraft). That storm did not have much (if any) in the way of "post-storm stratus", since we had an awesome view of the backside of the updraft and backsheared anvil after driving just a little ways away from the storm. So, it may have been sunlight hitting off the back of the updraft tower, reflecting down into the clear slot made by the RFD.