Stan Rose
EF5
No, that is not a debris ball. Its a cyclonic signature on velocity, debris shows up in reflectivity and CC (there was a small CC hole in this case as I recall, not sure if it was that scan or afterwards.)
-
While Stormtrack has discontinued its hosting of SpotterNetwork support on the forums, keep in mind that support for SpotterNetwork issues is available by emailing [email protected].
2015-03-25 EVENT: TX/OK/AR/MO/IL/IN
- Thread starter Adam Lucio
- Start date
Stan Rose
EF5
Thanks Zack--it's fairly clear early in the video, not so clear later when the multiple power flashes were occurring (which is what I saw on TWC). Looks fairly diffuse even in this video, almost like a strong gustnado.
calvinkaskey
Guest
- Joined
- Feb 17, 2014
- Messages
- 384
It is easier to see on that type of radar scan but it shows up well on regular radar reflectivity. Supposedly the first time it showed up was in 1985 in a huge F-4 (prob F-5) that travelled 64 miles in north central pa. Radar was not as sensitive or detailed back then either.
calvinkaskey
Guest
- Joined
- Feb 17, 2014
- Messages
- 384
Wow! Yeah just a little dust with the 100 mph winds of that dust devil. It makes me want to laugh and smack him at the same time. Whole pieces of roofing is flying around.
Jake Orosi
EF4
They did not seem to think so. Going back to Twitter again, around a half an hour before the Moore event, we have these:
Obviously I don't have the data NWS Norman had (nor the skill to interpret it if I did); but I see no reason to necessarily believe they made a mistake in their forecast. Sometimes a storm with low tornado potential produces a tornado; that's why it's "low" potential and not "zero" potential. But obviously something wrong happened in Moore during the event itself and while I'm not interested in finger-pointing or criticism, it does look like there's a lesson to be found somewhere in today's events.
Stan Rose
EF5
You may want to be a bit more clear in your future posts. I assumed you were referring to the velocity image that was posted by S Henry, since it was the last image posted before your question about debris balls. it then appears you went back and edited your post, so it appears you were asking D Robinson. And I'm not sure who you were referring to in the following post (someone you want to 'smack') but if it's me please be explicit, since that would be an inappropriate post
ChristianT
EF0
I was also somewhat discouraged by the lack of warning in Moore. Moore however was not the only spot that concerned me. There was also at least 1 cell in northern Arkansas that had a pretty classic velocity couplet on it and also just a severe warning.
Not sure what was going on in Norman but they flat out dropped the ball (unless there was some sort of glitch). That storm went up very rapidly west of OKC. There were a few wrap ups on radar but were obviously undercut by outflow. I get that. However, as that storm actually entered metro OKC the southern end of that storm surged east and latched onto a boundary. It developed a couplet very quickly. Looked pretty clear that an outflow dominant hailer had changed characteristics rapidly. The couplet was very defined. Then a report of a tornado came in and there still wasn't a warning. I know the situation was rapidly evolving but it was obvious it briefly at least became tornadic.
Jesse Risley
Staff member
I see both sides of the perspective from the Norman/Moore area.
I don't know what the internal NWS criteria is for issuing a tornado warning, or perhaps, more specifically, what OUN's individual threshold may be if a WCM at a specific office can have a somewhat unique set of criteria for that individual office.
With that having been said, monitoring the situation from home, the storms that fired west of OKC were within what I would argue was a justifiable blue box zone for basically a SVR threat. Hence, I see why the Tweet was posted regarding the tornadic threat being nullified, with the undercutting cold front and outflow dominant environment that was present. As others have noted, it appears that the situation changed rapidly with the interaction of an existing OFB. It's not uncommon to see storms with similar mid-level rotation in an environment that, for all intents and purposes, otherwise isn't conductive to tornadogenesis, thus the hesitation to issue a tornado warning. I can see where in this case a legitimate oversight from a warning forecast point-of-view is certainly possible, i.e., this isn't as clear cut of a "you dropped the ball big time" as other cases might be, or if nothing else is accentuates how fluid the atmosphere is and how quickly a situation can change where even a person with relative expertise cannot always be able to accurately issue tornado warnings with substantial lead times in certain environments where the threat may be far more dubious.
Since I don't know what the criteria normally is for a tornado warning vis-a-vis OUN, I can't really jump on the criticism bandwagon yet, although I did notice that the first warning was apparently a mistake and had to be re-issued for the Moore area. With that being said, there probably is cause for the NWS to re-evaluate what happened here and perhaps look at how the protocol could be modified in the future to try and issue a correct warning with more lead time in a similar environment. I'm also willing to bet that some of the damage reports, especially east of I-35, were in fact related to straight-line winds and/or gustnadoes, which, if the damage survey does confirm that was the case, were covered by SVR warnings relative to that specific type of damage.
If nothing else, aside from all of that, the standard caveat always applies: you were under a SVR thunderstorm watch, and in any such environment, tornadoes can develop with little or no advanced warning. Sometimes these things are going to happen and the NWS cannot always offer substantial lead time, but there is also room to learn from certain situations to prevent a future repeat from a warning standpoint too.
I don't know what the internal NWS criteria is for issuing a tornado warning, or perhaps, more specifically, what OUN's individual threshold may be if a WCM at a specific office can have a somewhat unique set of criteria for that individual office.
With that having been said, monitoring the situation from home, the storms that fired west of OKC were within what I would argue was a justifiable blue box zone for basically a SVR threat. Hence, I see why the Tweet was posted regarding the tornadic threat being nullified, with the undercutting cold front and outflow dominant environment that was present. As others have noted, it appears that the situation changed rapidly with the interaction of an existing OFB. It's not uncommon to see storms with similar mid-level rotation in an environment that, for all intents and purposes, otherwise isn't conductive to tornadogenesis, thus the hesitation to issue a tornado warning. I can see where in this case a legitimate oversight from a warning forecast point-of-view is certainly possible, i.e., this isn't as clear cut of a "you dropped the ball big time" as other cases might be, or if nothing else is accentuates how fluid the atmosphere is and how quickly a situation can change where even a person with relative expertise cannot always be able to accurately issue tornado warnings with substantial lead times in certain environments where the threat may be far more dubious.
Since I don't know what the criteria normally is for a tornado warning vis-a-vis OUN, I can't really jump on the criticism bandwagon yet, although I did notice that the first warning was apparently a mistake and had to be re-issued for the Moore area. With that being said, there probably is cause for the NWS to re-evaluate what happened here and perhaps look at how the protocol could be modified in the future to try and issue a correct warning with more lead time in a similar environment. I'm also willing to bet that some of the damage reports, especially east of I-35, were in fact related to straight-line winds and/or gustnadoes, which, if the damage survey does confirm that was the case, were covered by SVR warnings relative to that specific type of damage.
If nothing else, aside from all of that, the standard caveat always applies: you were under a SVR thunderstorm watch, and in any such environment, tornadoes can develop with little or no advanced warning. Sometimes these things are going to happen and the NWS cannot always offer substantial lead time, but there is also room to learn from certain situations to prevent a future repeat from a warning standpoint too.
Skip Talbot
EF5
What a tragic and fascinating event Moore was. This is going to be a great one for a case study. After a few brief glances at the radar it looks like a QLCS mesovortex tornado after an outflow boundary interaction. Snyder and others have pointed out that complex certainly had an embedded supercell in it and also suggested the tornado was supercellular, but it looked like the area that I'm calling a mesovortex occurred in a bowing portion of gust front. You can see the complex propagates rapidly to the south toward that outflow boundary, like it's reach out for it, and then that boundary gets pulled right in. The other cells in the line remained behind the outflow boundary, but this storm extended noticeably further south. You can trace that outflow boundary on the radar and see the inflow notch kink it makes.
Here's that embedded supercell complex showing the double hook. The mesovortex looks like it's coming off a bowing portion of the RFD gust front or flanking line.
Here's that embedded supercell complex showing the double hook. The mesovortex looks like it's coming off a bowing portion of the RFD gust front or flanking line.
rdale
EF5
To clarify OUN's twitter / Facebook post... One of the local TV stations was getting reports of gustnadoes along the surge in SW OKC and breathlessly issuing their own Tornado Warning for Oklahoma City itself. Their post intended to clarify why a TOR wasn't being issued for a gustnado.
Based on the limited number of tornadoes - a blue box was appropriate. But that also brings a question better served in a another thread
But why bother differentiating SVR/TOR boxes? Both can cause the same type of damage, so why do we tell the public the different meteorological causes?
Based on the limited number of tornadoes - a blue box was appropriate. But that also brings a question better served in a another thread
But why bother differentiating SVR/TOR boxes? Both can cause the same type of damage, so why do we tell the public the different meteorological causes?
TiffanyR
EF0
- Joined
- Mar 14, 2013
- Messages
- 12
Release from OUN: http://www.srh.noaa.gov/media/oun/releases/20150325-MooreRelease.pdf
Jake Orosi
EF4
Neat! So it seems as if Norman didn't misidentify the event after all - it actually started out as a straight-line gust front, which logic says should undercut any possible tornado inflow; and since they already expected the gust to be damaging, the inevitable damage reports just seemed to support their initial interpretation. In the 2333z radar image Skip posted, the inflow notch looks VERY subtle to my (untrained) eyes. I daresay the only reason we can even identify it now is because we know where to look for one, because of what we know happened later - information the NWS of course didn't have at the time.
The fact that the television station's live picture seems to show characteristics of both a straight-line gust and a tornado makes more sense now too.
The fact that the television station's live picture seems to show characteristics of both a straight-line gust and a tornado makes more sense now too.
chrisbray
EF4
So I have a question, and I don't mean to call out specific people or teams in a negatively light but I want to see it addressed. On the tornado video of the Sand Springs area from basehunters that has become quite popular on social media, the intro the video states they don't condone hiding under an overpass to ride out a tornado, but it was a "very special set of circumstances" that led them to do just that. But what was the special set of circumstances other than them wanting to catch up to and document a tornado?
James Hyde
EF0
This is a quick gif from the TDWR just S of Moore via Kiel Ortega at the NWC. The C-Band characteristics make the outflow boundary clear as day and how it interacted with the parent cell. I hope to get a similar loop together tonight with a street map.
