Storm Australian Severe Weather Forum
Severe Weather Discussion => Australian Severe Storms, Weather Events and Storm Chasing => Topic started by: Brad Hannon on 15 January 2011, 04:34:38 PM
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Hi all, despite a somewhat lacklustre radar return for these days John and I hit the jackpot again with 2 very rewarding days chasing amidst recordbreaking dew points!
Wed 12th Jan, HP Supercell near Bundure (north of Jerilderie):
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Thurs 13th Jan, Classic supercell Deniliquin to Heathcote (pics shown from Deni to Mathoura):
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And one more that I couldnt squeeze into the previous post :)
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Brad,
Can you point out the supercells on radar? I've looked at the yarrawonga radar and I'm not sure where you are talking about the supercells are on the 13th?
Jeff.
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Hi Jeff, as inferred in my initial post the radar return is not exciting and we noted that at the time. There were not supercells plural, just one on the north-eastern end of a cluster of cells that all produced low bases and tried to organise in the surface northeasterlies. This is yet another example of how inadequte our radar system is and a real worry when you have a surface based rotating storm heading towards Echuca-Moama and there is no severe warning on it. At least there is some coverage there however, as other areas we chase have virtually no radar coverage at all. Yarrawonga 128 shows the cell develop north of Deni at 12.40'ish and it tracks south to Echuca. We were on it from Deni where it developed a phenomenal wall cloud in front of us which is the first pic. It's development and motion was very fast as you can see from the times in my pics, and this may have affected radar tracking of the cell I guess.
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Now i've had some time here are some more images from the 13th Jan:
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And some more images from the 13th Jan:
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And a few more images from the 13th Jan:
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This is yet another example of how inadequte our radar system is and a real worry when you have a surface based rotating storm heading towards Echuca-Moama and there is no severe warning on it. At least there is some coverage there however, as other areas we chase have virtually no radar coverage at all
There is no problem for our new doppler radars in picking up supercells at a distance 100km. You infer that the yarrawonga radar is somehow inadequate and yet it is the same new model as the Sydney and Brisbane radars which both easily pick up supercells at 100km. See attached images. Yarrawonga to Deniliquin is also very flat. This radar is not inadequate.
Looking at the images you posted of the 13th and using the radar images one can only assume that these were weak cells that were outflow dominant. There is no indication otherwise such as cell intensity or deviation on radar or doppler wind field evidence. Why would the BoM put a warning out for them?
I do like the cells however on the 12th, they look far more impressive structure wise.
Regards Jeff.
P.S in this first radar image from Sydney there is a right mover near kandos about 140km+ from the radar over mountains and through other storms and yet still very obvious. The other images speak for themselves.
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sorry there seems to be a glitch in posting multiple images
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last post with the yarrawonga return on the 13th at 1:20pm for comparison.
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Yeah you must be right Jeff :rolleyes:, and very predictable, it was obvious from your first post where you were heading. Little point entering another discussion with you but..... It would seem you infer that the 13th was not a supercell, and if so you are wrong. The definition of supercell is clear and in the conditions we are getting down south this season the occurence of supercells has been quite regular. This day was another where the conditions were right, add to that the heating that occured at midday and the very high dew points that were present. This cell cycled and rotated strongly and persistently for at least an hour (being very conservative there mind you) producing a number of iterations of an impressive, low and clearly rotating wall cloud with funnels which almost rain wrapped several times. We also had strong rotation and an RFD cut with funnel occur as we stood and watched north of Echuca. We have full video coverage too. If you cannot or choose not to see the obvious rotation in the shots and call it outflow so be it, we expected that. If you dont call a storm with a persistently rotating updraft a supercell thats your call. Otherwise you must think this cell was not rotating and that we are making it up and again you are wrong. If you rely on radar alone and discount any storm that isnt large with a dark core and deviating I think you are kidding yourself. The radar was inadequate in my opinion - the reflectivity did not convey the nature of this storm, period. I'm sure John will have an opinion on that as he is well versed in that topic which I am not.
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Without wanting to get involved in the technical details which I'm not qualified to do, as I understand it the radar is mainly showing rainfall (as well as wind). If the cells you were seeing showed supercell characteristics as described is it possible that the actual rainfall dump wasn't that heavy at the time for whatever reason? Which would explain the difference between the on ground observations and the radar returns.
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Hey Guys,
Hope all is well. Richary, I was thinking the same thing. I also don't have the experience either, but as the radar shots are showing rainfall, I wonder if a LP SC would still show up on rainfall radar with the same pattern/features as a SC that is dumping loads of rain?
Very nice shots Brad and John, the wall cloud is very impressive.
Regards,
Chris
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Yarrawonga is NOT the same type of weather radar as the capital city Dopplers - eg. Sydney/Brisbane/Melb
Yarrawonga: WSR 81C C Band
http://www.bom.gov.au/weather/radar/info/VIC.info.shtml#49 (http://www.bom.gov.au/weather/radar/info/VIC.info.shtml#49)
Sydney (Terrey Hills): Meteor 1500 S-band Doppler
http://www.bom.gov.au/weather/radar/info/NSW.info.shtml#71 (http://www.bom.gov.au/weather/radar/info/NSW.info.shtml#71)
Melbourne: M1500-S1, 1º S-band Doppler radar
http://www.bom.gov.au/weather/radar/info/VIC.info.shtml#02 (http://www.bom.gov.au/weather/radar/info/VIC.info.shtml#02)
So you cannot directly compare the resolution/sensitivity of images.
cheers, Michael
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Michael,
I don't believe that the Yarrawonga radar understimates the echoes that much that a supercell at 100km would look smaller than the echo of a weak shower. The BoM would not install a radar that doesn't pick up severe storm echos in that region when severe storms there are frequent.
Do you think the storms on the 13th are supercells? What is your opinion?
Regards Jeff.
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Brad,
Why don't you post this rotating evidence and shut me up? Go for it as I genuinely want to see supercells but if you or anyone elses posts images that don't look all that impressive and claim supercell status I will question it. Please post this awesome cyclical supercell evidence.
If you don't like that than don't post publicly? :rolleyes:
BTW did you see that I complimented the storms you chased on the 12th? I like them and think that they are definately severe storms. You chose to ignore that and take offense instead, and that is not my problem.
And if you think my post was somehow a personal attack you are dead wrong as I only questioned the storm from yours and the BoM's evidence and not your intent. Your response towards me in reply however strongly questions the integrity in my response to you which is not warranted and uncalled for.
Jeff.
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Michael,
I don't believe that the Yarrawonga radar understimates the echoes that much that a supercell at 100km would look smaller than the echo of a weak shower. The BoM would not install a radar that doesn't pick up severe storm echos in that region when severe storms there are frequent.
Do you think the storms on the 13th are supercells? What is your opinion?
Regards Jeff.
Jeff, Firstly Michael made no comment about the radar underestimating anything, simply pointed out your assumption about the radar specs was wrong. Secondly and not for the first time I will point out we saw a supercell, not multiple.
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Hell. I have not posted much in the past few months but this discussion, whilst informative and offers many opinions has probably gotten a little heated. Please guys, let's just keep things on a level heading. I know little about supercells so I will never post any information about my discection of such things, but there seems to be some friction between what someone interprets and what someone replies to here. You are both seasoned chasers and yes, you both have differential views on what one sees.
The amount of information just in the replies re the supercells and conditions is so informative that any new person reading this would be astounded by the descriptions of events, but having said that there has to be some medium when replying. Sure, look where i am up here in Darwin there are so many that have views on storms and set ups that beggars belief and I for one do not post for fear of retribution (probably something I should change given the comments well made here!) and set things right!
There's a few questions that obviously need to be answered here:
(1) Are they supercells and if so what type?
(2) Live observation and chasing does hold credance because the chaser in question obviously knows what he is seeing or not?
(3) MB posted the radar links for each site....perhaps some interpretation of the three can be organised and agreed to?
From my knowledge of storm set ups and supercells the blatent thing that sticks out is wind shear. They alone would dictate the storm character so what do the doppler and base reflectivity show given the wind shear properties and conditions?
I read the comments with personal interst, but as a mediun even in the heat of the moment try and remain calm and give as much factual evidence as possible (although it seems it is already given!) and let's have a discussion. Like i mentioned, you guys are the ones that see supercells often so giving the information as such given is a learning experience not only for myself but newbies..
I do respect everyone's opinons and yeah, some have more Met experience and chase experience than others....so share it and if someone is wrong or misguided (I've found my own niche of people up here beleive me) then as a forum members need to channel this frustration for the betterment of the education value of the forum and not make attacks....
:) Mike
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Why don't you post this rotating evidence and shut me up? Go for it as I genuinely want to see supercells but if you or anyone elses posts images that don't look all that impressive and claim supercell status I will question it. Please post this awesome cyclical supercell evidence.
If you don't like that than don't post publicly? :rolleyes:
BTW did you see that I complimented the storms you chased on the 12th? I like them and think that they are definately severe storms. You chose to ignore that and take offense instead, and that is not my problem.
And if you think my post was somehow a personal attack you are dead wrong as I only questioned the storm from yours and the BoM's evidence and not your intent. Your response towards me in reply however strongly questions the integrity in my response to you which is not warranted and uncalled for.
I have posted sufficient pics and dont intend to post any more on this storm to satisfy you. As I have been informed, a number of well-reknowned US chasers have commented on the same pics you claim to be unimpressive as evidence of a left moving supercell - go figure.
Not sure who has used the descriptive term awesome, dont think it was me.
Obviously it goes without saying, you can question all you like whenever you like but the reality is you wont accept the answers from me. On the topic of questions, Im fairly confident from previous experience that I wouldnt get a straight answer to any question directed at you, hence this time I havent asked the pertinent question of what is a supercell? If you subscribe to the commonly accepted definition it wouldnt suit your apparent position to answer.
I am open and respond to any reasonable questions and comments on public posts - see my first reply. I dont however accept what appears to be a considered attack on my integrity in your second post where you discount my observations, ignore them completely and deride the storm as weak and outflow. It seems to me you always intended to go down that path and I've seen it before. I expected it.
Did I see you commented on the 12th? yes and I replied as such - read my subsequent post! In my opinion perhaps you could adjust your posting style, post more in context to others posts and read details closer and that would help but hey thats just my opinion....I wonder if anyone else thinks the same.
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Noted Mike and agree with you.
The info MB posted, while mildly interesting, is completely superfluous to this discussion, as I can't see that attenuation would be an issue with only weak echos around.
Jeff's questions are fair enough. The radar stinks. This is a BoM radar. If this doppler radar is so crap that HPs look like stuff I would not bother opening the blinds for then the BoM have a problem. There is nothing of note in that radar on either velocity scans or the base reflectivity.
Regarding the pictures. 12th - there is a developing shelf cloud which reaches its apogee in pic 3798. Pic 3763, in particular, has what I would call inflow stingers, but this suggests nothing other than the presence of a fairly deep inflow layer. The precip looks consistent with radar, nothing that seems particularly visibly intense. Was there any large hail reported? The pictures, IMO, don't show anything that looks obviously HP. Such a claim would rely on you guys seeing, and preferably videoing, clear rotation (on a tripod). There is nothing circular about the formation that would suggest strong rotation, which can be quite dicernible to the naked eye in such cases.
13th: How can this possibly be a classic supercell when the precip is on the right side, where the RFD would be if it was a supercell? I am assuming that lowered area is regarded as the wall cloud(?), in which case inflow would be in behind that with the RFD; ie very wet, wrapping around the back side? -- flip this structure and imagine what would the radar echo would look like? Or, are you saying it is anti-cyclonic? As it view them, I interpret the images as a shelf cloud developing from a near, side-on perspective, and the sequence of events (via the pics) reinforces this. This is a pic-based interpetation - if you have video that might reveal a different story but that is not up yet.
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David, I am astounded at your post for various reasons. First I think you should show some more respect when you enter a discussion. You come across in a very condescending and disrespectful way IMO and Ive seen it and called you on it before. Michael posted info in response to an incorrect assumption by Jeff, simple. If you read the thread it was not superfluous at all.
I dont think anyone has said Jeff's questions are unreasonable. It is the manner in which they are asked, the apparent lack of acceptance of the response and the apparent complete ignoring of field observations that is the problem. For whatever reason you are communicating in a similar fashion and have done so before. This is one reason why there is very little posting on this forum anymore and it is not the forum it could be.
No one has said anything about the radar return of either day being great, in fact I said is was lacklustre in my first post so no need to slam it like there is some discussion about how good it is. However, John has added his technical interpretation and with his training and skills in that field it should be respected. Apparently you see nothing so it seems you are at opposite ends of the spectrum on this one and once again in this overall discussion someone's observation is completely ignored and utterly dismissed. Dejavu anyone.
Re the 12th. There was no hail where we were and Im not aware of reports but so what, we were in a sparsely populated area, close but ahead of the storm and since when is hail essential in defining a supercell. Again the definition is ignored with a personal adaptation to suit a position. The storm had a distinct green tinge to it at times but as we know that is no guarantee of hail but a fair hint and I've seen enough big hailers to know. We have already stated it was a HP but that has been discounted and our obs ignored so why hint that a claim would be reliant on us seeing what we saw. Yet another clarification is required to point out that no one has described strong rotation (I know what strong rotation is) - you introduced that description. There was some rotation in the base feature and some curvature in the inflow discernable to the naked eye but Im guessing you wont accept that observation so again whats the point in you suggesting it as a possibile way of satisfying you.
Re the 13th. I cannot enter a technical discussion on this and wont pretend to. All I can stick to and reinforce again is that this was not outflow dominant but an organised updraft that was rotating and cyclic over a long period. Again you choose to ignore and dismiss our observations completely as incorrect or lies (not that you've said that but suit yourself) and use selective interpretation of stills to suit your position.
There is nothing wrong with wanting to know more about a storm we saw but the way you guys go about it is atrocious.
Further, I think you would regret the bone-headed comment David if you knew who the reference was made to. Just not necessary.
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Whilst the comments have been somwwhwat heated, I trust the three of you have vented your frustrations out and can now rest in peace.
I must admit that the technical aspects of the discussion has been very enlightening to say the least. As an outsider to supercell thunderstorms per se it has proven to me that all is not what it appears when commenting on such things. You see guys, this is why I have stayed with this forum for so many years. The information obtained is second to none. I have found no other forum in Australia that has the type of in-depth information and - sometimes colorful critique - on storms, particularly supercells.
I could see from the very first posts that this would open a hornet's nest once it gathered momentum. I'm not backward in coming forward if there is subject matter than I am experienced in and can back it up with facts, and I think that those members who disbelieve or critic any explanations should take a deep breath, ask a few questions first (particularly if any person was not actually chasing any particular storm I, they or you had for discussion topic material). So for perhaps this purpose it is unappropriate to grab each other by the throats and defame each other. If you're wrong then admit it, if the facts add up and the explanations are correct then accept it and move on. I've found it's better to discuss the events and indeed, there can be healthy debate - even heated which actually is a healthy thing in some respects - but let's go with the facts and learn from it. If these same facts prove down the track to be wrong - by some explanation from other resourced areas and resubmitted - then great everyone learns from it.
I'm waving the white flag atop a hill here....don't let the keyboard be your agressor...I do it sometimes when confronted with dimwits arguing against something to which I have experience and I fully understand that if those folk have the facts that shoot me down in flames, then hell, I have to accept it because they have the Met knowledge and education to back such things up, but I will stand my ground - as any of the members have the right to - to voice their opinion. Remember that if you openly debate subjects pertaiing to the technical aspects of Meteorology and you don't have the qualifications to concur...you leave yourself wide open to replies from those that do have the expertise!
Okay...now back to those discussions because I'm finding them highly informative and educational!
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Wow! So much discussion going on here. Don't mind a good old fashioned science discussion but I can't see the need for insults from anybody. Needless to say, I am staying out of this one except for one thing. The whole east Australia vs elsewhere pops up every now and again. As an east coaster I must say that I appreciate a good storm setup anywhere in the country. Certainly been some excellent storms in Vic, SA, WA and NT (as I just found out) this season. As for the NE NSW/SE Qld season, yes it has been poor but I saw probably one of the best structured storms I have ever seen. One good storm is enough to keep me happy for a while and is enough to keep jealously at bay :)
Michael
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Hi,
I go away for 24 hours without internet coverage, and WOW as Michael Thomas suggested. I agree with what Michael also suggests lovely pictures of nice storms on a flat landscape. Does a storm have to be a supercell to enter the hall of fame? I have seen and taken nice images of non-supercells including with and without lightning.
Supercells? - can we say possible - probable or is it not warranted this time? After all, it is suggested the radar was useless in this case for whatever reasons. And now video is not required to show a deep rotating updraft - so what evidence do we look for then? Hail - you had a green tinge - and yes Brad that is not absolute evidence or should I say not for hail size at least. I have seen many green tinges produce nothing at all! So what evidence should you provide to indicate these are 'definite' supercells. For instance, I intercepted a 'probable' supercell yesterday near Dorrigo as Jeff pointed out with interesting behaviour.
What really makes me wonder was a classic supercell claim by Brad! Brad this in my opinion is a structure what they coined as a classic supercell:
http://www.australiasevereweather.com/video/movies/flash_video/2006-2007_stormchasing.htm (http://www.australiasevereweather.com/video/movies/flash_video/2006-2007_stormchasing.htm)
http://www.australiasevereweather.com/video/movies/2007/classic_supercell_rotation_february_7_2007.wmv (http://www.australiasevereweather.com/video/movies/2007/classic_supercell_rotation_february_7_2007.wmv)
(http://www.australiasevereweather.com/photography/photos/2007/0207jd19.jpg)
You say you have video, post the video and if I can see strong rotation on video, then I may become more convinced. I will be posting my video perhaps tomorrow evening. As we have suggested in the past - you guys have made the claim. We are not totally convinced and have asked for some evidence. You can also ask for more evidence if you so wish of our storms if we claim supercell status.
As to the classic supercell Brad, you are the one who suggested such, I don't agree I'm afraid.
And for the record, Jeff is a respected chaser with many years of experience who has a good eye for detail. I often ask him for opinions - I always consult with someone for an opinion on something as we know this is all part of a continuum.
Regards,
Jimmy Deguara
EDIT - Changed 'Michael Thompson' to 'Michael Thomas'
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I dont think anyone has said Jeff's questions are unreasonable. It is the manner in which they are asked, the apparent lack of acceptance of the response and the apparent complete ignoring of field observations that is the problem.
I am saying that I think Jeff's question were reasonable both in content and ‘tone’.
Re the 12th. There was no hail where we were and Im not aware of reports but so what, we were in a sparsely populated area, close but ahead of the storm and since when is hail essential in defining a supercell. Again the definition is ignored with a personal adaptation to suit a position.
Thanks for the clarification, but how do you extrapolate my 'definition' of a supercell from me asking such a simple question.
Yet another clarification is required to point out that no one has described strong rotation (I know what strong rotation is) - you introduced that description.
and
There was some rotation in the base feature and some curvature in the inflow discernable to the naked eye but Im guessing you wont accept that observation so again whats the point in you suggesting it as a possibile way of satisfying you.
And once again, I did not that say you claimed seeing strong rotation for crying out loud. :rolleyes:
My general query is on what grounds are you claiming that these two storms 12th/13th were supercells?? Some cases are visibly obvious of course, I don't think that on the photo evidence available here, that either of these storms are in that category. So:
- We have no radar to go by.
- You did not see strong rotation.
- You say it was 'inflow dominant but that mans nothing in the context of this discussion? (Also, how do you observe this inflow dominance, how can you confirm this. There is clear evidence of a gustfront in your pics).
- You say that there was 'rotation', in the 'base features'. I say, in the context of supercell definition, that this is not evidence of anything.
- Curved inflow bands – sorry, I just can't see them in your pics, but, yes, I agree it is not common to see curved inflow bands unless the storm has a meso.
Re the 13th. I cannot enter a technical discussion on this and wont pretend to. All I can stick to and reinforce again is that this was not outflow dominant but an organised updraft that was rotating and cyclic over a long period. Again you choose to ignore and dismiss our observations completely as incorrect or lies (not that you've said that but suit yourself) and use selective interpretation of stills to suit your position.
This is not a technical question!! I am asking you how you can reconcile your photo with the precip. Think about it, it’s a simple question!
Also you categorise storms as HP, classic etc based on field obs. How can you do this if you don't understand my question? The delineation of these 'storm morphologies' is based on radar criteria. That means you must essentially have a good field example (and understanding thereof) to make such a claim. Yet you are saying this is too technical? I normally don't start classifying storms until I have seen radar, although, yes, it is obvious in many cases.
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Does a storm have to be a supercell to enter the hall of fame?
Supercells? - can we say possible - probable or is it not warranted this time? After all, it is suggested the radar was useless in this case for whatever reasons. And now video is not required to show a deep rotating updraft - so what evidence do we look for then? Hail - you had a green tinge - and yes Brad that is not absolute evidence or should I say not for hail size at least. I have seen many green tinges produce nothing at all! So what evidence should you provide to indicate these are 'definite' supercells. For instance, I intercepted a 'probable' supercell yesterday near Dorrigo as Jeff pointed out with interesting behaviour.
What really makes me wonder was a classic supercell claim by Brad! Brad this in my opinion is a structure what they coined as a classic supercell:
http://www.australiasevereweather.com/video/movies/flash_video/2006-2007_stormchasing.htm (http://www.australiasevereweather.com/video/movies/flash_video/2006-2007_stormchasing.htm)
http://www.australiasevereweather.com/video/movies/2007/classic_supercell_rotation_february_7_2007.wmv (http://www.australiasevereweather.com/video/movies/2007/classic_supercell_rotation_february_7_2007.wmv)
(http://www.australiasevereweather.com/photography/photos/2007/0207jd19.jpg)
You say you have video, post the video and if I can see strong rotation on video, then I may become more convinced. I will be posting my video perhaps tomorrow evening. As we have suggested in the past - you guys have made the claim. We are not totally convinced and have asked for some evidence. You can also ask for more evidence if you so wish of our storms if we claim supercell status.
As to the classic supercell Brad, you are the one who suggested such, I don't agree I'm afraid.
And for the record, Jeff is a respected chaser with many years of experience who has a good eye for detail. I often ask him for opinions - I always consult with someone for an opinion on something as we know this is all part of a continuum.
Regards,
Jimmy Deguara
Hi Jimmy,
Re your hall of fame query - no absolutely not! I agree and let me say that these were no hall of famer storms in my book - never said they were. Others have attributed the terms awesome and strong to this discussion, not me nor John. Now you are adding Hall of Fame. Please let that be noted. This was not even one of my favourite storms of this season for structure or photographic beauty but it still did what it did.
Of course the words possible or probable have an important place in storm description but I am sorry, if a storm has a rotating updraft that persists for a long period of time and I observe that entire period of storm behaviour, I will call it a supercell. No visible hall of fame structure necessary, no large hail, possibly even regardless of a perfect radar (as in this case), no other extra provisos. I learnt the definition via you and other chasers initially and I subscribe to it. Perhaps you cant confirm a persistent rotating updraft in your cell yesterday? If you can (and hopefully you were able to) then that is sufficient evidence for me to accept a call of supercell. If it was persistently rotating but you choose to use the term probable, then that is just sugar coating to appease who and pointless so I hope that is not the case.
The radar was uninspiring to me as a novice in radar and of course does nothing to convince sceptics that anything great occured but if you read Johns information and interpretation of the radar, especially for the 13th it was not useless. There is no monster return thats for sure but according to him it clearly shows sufficiently that a supercell is not a wild concept for this day. I'll take that advice from him and respect it for what it is.
We have video, it was running most of the time. When I have time I will watch it for my own interest but I have no intention of posting any clips here or on any other forum. If I got a great tornado on video and it was good enough footage I would consider that for sharing on a forum but nothing more. We have posted pics, we have provided obs and John has provided sufficient technical opinion on both storm structure and radar. These have either been ignored, dismissed or misunderstood but we've been down this track before so Im not surprised.
Re your comments about my claim of classic supercell. Lets just say for a moment that people can accept our observation that a supercell occured then it has to fit somewhere in the continuum of the supercell spectrum doesnt it! This was clearly not a HP and was not in my observation an LP either. I understand enough to know that storms can transition or sit somewhere along that continuum at a given time. During the chase I discussed the nature of the storm with John and he was adamant that it was a classic and he noted the structure and separation of the updraft/downdraft regions at the time. So in my post I called it a classic. Add to that (as has been mentioned) several reknowned US chasers have commented on the images (and perhaps radar but Im not sure) that this was a left moving supercell so its type has to be classified and I feel comfortable despite your query/comment which you are entitled to make.
Your image/video doesnt add to my understanding of supercell structure Jimmy please, give me some credit, although I did enjoy seeing that video again! If you note our pics and consider the conditions on the day incl the surface dews, low cloud mostly obscured our view of structure above what is shown in the pics so the comparison doesnt help, not to mention we were much much closer to the base than your example so its not relevant IMO.
We are not totally convinced you say? Thats an understatement regarding Jeff and to some degree David so I guess you can speak for yourself on that. They have completely dismissed the event as uninteresting, showers and various other slights and inferences. By extension it seems reasonable to assume they think we are liars or fools.
I note your comment re Jeffs experience and know very well that he chases. Doesnt change anything I have said or what my expectations are on a forum. Regarding consulting, I agree but dont forget John and I chase together most times and discuss these things at great length on long road trips and in this case and indeed others, other reknowned chasers have been consulted which has already been mentioned.
The lack of verbal reports from me in an exceptional southern season is no coincidence. After simply trying to share a storm experience photographically with other forum users I am exhausted with this outcome and unimpressed with the blunt, rude and unidirectional mode of communication that has yet again reared up on this forum again. If you think it isnt noticed by those reading the posts I suggest you are wrong and that is only detrimental to the forum.
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My general query is on what grounds are you claiming that these two storms 12th/13th were supercells?? -
You say that there was 'rotation', in the 'base features'. I say, in the context of supercell definition, that this is not evidence of anything.
could you please explain David how a wall or shelf cloud may be rotating without a rotating updraft above it. I imagine the point you are making is that the base itself (or a visible updraft) needs to be persistently rotating to indicate a supercell.
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Great Pics! :)
A couple more pics from the same cell.
(http://img843.imageshack.us/img843/1694/deniliquinsupercellweb2.jpg)
(http://img220.imageshack.us/img220/3339/deniliquinfunnelweb.jpg)
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Here we go again Brad.
Based on your response, I cannot clearly answer your questions because I require you to answer a few key questions and take a few key actions in order to do so. So don't take offense if I don't answer the questions you have asked. But never mind I doubt you will anyway.
Brad wrote: I learnt the definition via you and other chasers initially and I subscribe to it.
Then why don't you accept my judgement of, based on your weak evidence here, use of the terms possible or probable at the least if you were able to accept what I suggested back then. Quite frankly, I don't think based on photographs posted there were any supercells but I have to give you benefit of the doubt because you were there. But you have written and argued a strong statement that requires some clarification. That is the whole crux of the argument here. I personally and neither does Michael Bath like incorrect titles on threads.
If you do not show more evidence of supercell as claimed I have to change the name of the title of this thread to possible supercells at the least. I hope you don't mind just for future readers' sake. It seems you are unwilling to show video that you have. It is so easy these days to download the video, shove it on a timeline, speed it up, render it, place it on Youtube and post the link. I have gone to great lengths and research to be possibly the first one to place a plugin on any of the weather forum that plays a wide range of videos from within the forum.
Brad wrote: Perhaps you cant confirm a persistent rotating updraft in your cell yesterday?
And probably never will. I will post what video I have and pictures of the hail size and people can make their own judgements. I don't think with the word probable, people are going to come at me for any form of inaccuracy or misreporting. They are welcome to do so including yourself! Will it take away from the excitement or beauty of the storm - not in my opinion.
Brad wrote: Of course the words possible or probable have an important place in storm description but I am sorry, if a storm has a rotating updraft that persists for a long period of time and I observe that entire period of storm behaviour, I will call it a supercell.
Yes you can call it be a supercell and you definitely have and it must make you feel better, but obviously to those for whom you have posted, they seem as I browse through posts, once again, unconvinced. Do you think we take lightly to spend a lot of our precious time to write posts on this or any other forum for that matter to try and educate you (Jeff has a family, David runs a business and I also have a growing family) to sit down and post these 'hard to convince you guys' posts? You know I do believe you guys 'know' it is a supercell and it must be hard to come back, post your fantastic pictures and then have a thread like this arise. This was not my intention even if you do not agree. Notice I commented on the supercell in Central Victoria and congratulated you. That was a supercell - in my opinion - I would put my money on it. But I was forced to intervene this time for obvious reasons - I am a moderator.
Brad Wrote: I'll take that advice from him and respect it for what it is.
What? You take his advice and not from any of us? Not even consider our experience in the field? Remember, we have to go with visual clues here. You have decided to omit radar as usless this time round.
Brad wrote: We have video, it was running most of the time. When I have time I will watch it for my own interest but I have no intention of posting any clips here or on any other forum.
Why not? I thought you learned this from me by now having chased that video on tripod is a great tool. I learned this when I stuffed up tornado footage in 1992! I promise you - Pintang, David, myself and other chasers who take video post it more often than not. They receive a far better response because you can see the dynamics in play better than in photographs don't you agree? You don't even need sound. We promise we will not comment on the quality of the video itself unless it becomes difficult to use it for evidence. Please provide more evidence such as video if you have any and we can comment on that. If you do not have timelapse on tripod, just say so! We will accept that.
Brad: These have either been ignored, dismissed or misunderstood but we've been down this track before so Im not surprised.
Don't use this line of attack once again. You are also ignoring ours - we stick to the point of asking for the evidence which you have ignored. So it is on par here.
Brad Wrote: I understand enough to know that storms can transition or sit somewhere along that continuum at a given time.
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Your image/video doesnt add to my understanding of supercell structure Jimmy please, give me some credit, although I did enjoy seeing that video again!
Of course you do and who taught you that first? I am telling you that the accepted classic supercell definition visually is similar to what I have posted. I can ssure you US chasers did not doubt that from a visual perspective. Note there is no shelf cloud but clean organised structure! You have chased Tornado Alley with me at least 4 times now and you cannot see from the image I posted that it indicates classic supercell structure by definition? There has been nobody around that has required to question it including a forum of US chasers! From the images you have posted, I do not see a classic supercell. We agree to disagree.
Classic supercells are generally rare from what I have seen in the literature in Australia. So are supercells may I add. Classic supercells do tend to have remarkable clean and organised structure. If you are no closer to the definition from a visually perspective and from what I have tried to portray in this image, then you should not be advocating yours as a classic supercell Brad.
Brad: During the chase I discussed the nature of the storm with John and he was adamant that it was a classic and he noted the structure and separation of the updraft/downdraft regions at the time. So in my post I called it a classic.
Yes I also get excited on the chase and sometimes call something a supercell or has supercell characteristics whatever, it is in the excitement heat of the chase and often in our forecasts, we do tend to try and formulate what may occur on the day. This is one of the reasons I look for video clues on top of the photographic evidence as well radar and other pieces of evidence on the day as well as adivce from others who may or may not have been there but still can offer there insight. I often ask David Croan (his scientific skills are second to none amongst the weather community) and Jeff as well as others for their opinions given they look for the signs that will convince them or not. It is ok to debate these points. Then further down I look for the typical types of behaviour, storm splits, deviant motion visually and on radar, distinct wall clouds, evidence of hailstones either from within or after the storm has passed. Once you have hail greater than 5cm, the odds increase dramatically!
Brad suggested: If you note our pics and consider the conditions on the day incl the surface dews, low cloud mostly obscured our view of structure above what is shown in the pics so the comparison doesnt help, not to mention we were much much closer to the base than your example so its not relevant IMO. We are not totally convinced you say?
The conditions on the day don't always provide evidence of what happened. For instance, there have been many predicted tornado outbreaks and conditions that indicate there would be a tornado outbreak but they congeal into a squall line.
Brad suggested:...not to mention we were much much closer to the base than your example so its not relevant IMO. We are not totally convinced you say?
Wrong here!
http://www.australiasevereweather.com/photography/photos/2007/0207jd48.jpg (http://www.australiasevereweather.com/photography/photos/2007/0207jd48.jpg)
http://www.australiasevereweather.com/photography/photos/2007/0207jd53.jpg (http://www.australiasevereweather.com/photography/photos/2007/0207jd53.jpg)
And how about from under it!
http://www.australiasevereweather.com/photography/photos/2007/0207jd56.jpg (http://www.australiasevereweather.com/photography/photos/2007/0207jd56.jpg)
Note the circular base - this was spinning overhead. 1100 metres above sea level, I think we were closer!
Brad Wrote: By extension it seems reasonable to assume they think we are liars or fools.
Now now - let's not go that far - you seemed to indicate similar again last year but certainly ask them directly if you wish. Because on the evidence provided by most other chasers, there is a certain level of trust, judgement and confidence you have in a chaser. Consider chasers such as Pintang, David Croan, Jeff Brislane, Michael Bath, Michael Thompson to name a few who always post what they see and are careful to describe what they see. If they are unsure, they will say that. They are also willing to accept constructive criticicm if need be - that's part of the learning process. We are all learning here! There are others I lack trust in based on what they report. They come post on here and I do not agree, I will challenge them. But that is simply my right to post an opinion. That is why we are here debating this long pain-staking and probably pointless thread. All because you have posted classic supercell and supercell on the thread! We strongly disagree.
Brad Wrote: Add to that (as has been mentioned) several reknowned US chasers have commented on the images (and perhaps radar but Im not sure) that this was a left moving supercell so its type has to be classified and I feel comfortable despite your query/comment which you are entitled to make.
If you are unwilling to share what someone wrote, then I cannot comment on it nor even consider it unfortunately!
Finally,
Brad Wrote: If you note our pics and consider the conditions on the day incl the surface dews, low cloud mostly obscured our view of structure above what is shown in the pics so the comparison doesnt help,
and
Of course the words possible or probable have an important place in storm description but I am sorry, if a storm has a rotating updraft that persists for a long period of time and I observe that entire period of storm behaviour, I will call it a supercell.
Brad, you seem to indicate ... "low cloud mostly obscured our view of structure above"
and then suggest you were able to confirm without doubt "...a rotating updraft that persists for a long period of time and I observe that entire period of storm behaviour".
In my opinion, these two are strong and almost certainly contradictory statements. Perhaps late night/early morning jitters.
I can assure using the Dorrigo example, since you make reference to it, probable supercell, I was in the cloud and could not see the structure at all, so I can assure you I will not be using timelapse to suggest I saw a deep rotating updraft. We will just have to rely on radar behaviour, deviant left motion, the 5.5cm hail (measured with calipers), the video footage of the rounded base which although shaky, will be evident, that it could provide clues to indicate probable supercell. The Bureau of Meteorology occasionally make statements about a storm being a supercell but I would not think this will be the case as relatively few people would have been affected. Conditions on the day if you would like to include them were deep layer shear, sufficient instability (model and soundings CAPE in the vicinity of about near 2000J/kg.
Another important attribute I have noted with a few supercells developing with low cloud obscuring view is that the supercell environment cleans the air locally because it tends to at least partially based on current understanding of supercell dynamics is able to drawn in its own inflow rather than being totally force fed. This was evident in this Dorrigo case as the low cloud suddenly is drawn in and the fact I could clearly see the base with low cloud surrounding it. Mesocyclone perhaps?
Regardless of the fact what I have tried to portray in this post, I doubt you will ever be convinced. Quite frankly I am not really interested whether you will accept what I say. But as I said I will have to change the title of the thread if all you will be showing us are these photographs. I asked for video if you don't mind and we will go from there if you wish. Do you have timelapse video of one or both of these events - yes or no?
Otherwise, I will likely not be responding from here.
Regards,
Jimmy Deguara
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Hi David and Jimmy,
I have read both your posts and can say I somewhat agree with some of your points and disagree with others. I do believe firmly that context has been blurred in some of your posts which can confuse readers and angles have been taken that are not relevant and dont need to be brought up in order to discuss this issue. There is little point persisting with this and referencing each one individually anymore. It is clear that you will not be convinced from my response and I will not be satisfied with yours.
Rather than inferring my chase experience and forcasting ability (which is totally irrelevant) is lacking and appearing to attack that, perhaps you can absorb the tech information and pics posted by John and respond to that although it seems that his contributions are being systematically ignored. I hope that is not the case.
In the interest of not being or appearing hypocritical I will acknowledge David I couldve addressed my 2nd post to Jeff in a different manner so I will apologise to him for that.
Jimmy, re you storm example and another example of where this discussion loses context - you seem on the attack like I have denigraded that storm - that was a ripper storm, no doubt a classic and I know you got under it and close. My comment was in reference to your image example that shows the vertical storm structure from long distance compared to our chase which was close the entire time. I dont think it was helpful that's all.
You want to see tripodded video and I can understand why but there isnt any. The chase was 95% on the road with storm motion not allowing that luxury. The video is dashmounted with very little timelapse per se and im fairly certain it wont change anything so that's that.
Re the title thread, I was actually going to suggest that the mods can change the title if it is their preference. Not that you need my blessing but go ahead thats fine. In fact, I realised afterwards that I shouldve posted in the existing thread for those dates.
Finally, Jimmy you say you possibly wont post on this anymore and thats your call. But why would you enter the discussion, address only posts by me and ignore any information provided by John? That could appear very selective so hopefully you will consider discussing some of the technical info, evidence or advice presented by John previously and today.
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John,
btw this post was made in response to your first post to me. You have moved things along, provided more photos so I will need some time to catch up.
This may be part of the problem, radar can lie...for various reasons which have been already stated here. It would not be the first time a storm in this area has not conveyed a true return. http://www.theweatherchaser.com/radar-loop/IDR493-yarrawonga/2010-12-08-00/2010-12-08-11. (http://www.theweatherchaser.com/radar-loop/IDR493-yarrawonga/2010-12-08-00/2010-12-08-11.) Watch closely any behaviour west of the NS part of the border form storms forming in this region, either miraculously ever storm strengthens as it approaches yarrawonga, or the radar misreads in this area, possibly due to beam interference along the murray (maybe trees near the radar site). This being said the storm in question on the 13th actually shows an orange core for part of its lifecycle, so perhaps its a little less showery than some may interpret.
and
Finally on the attenuation point David are you aware of the refractive index of air with a minimal dewpoint depression and tropical drop size. It wouldn't be the first time a particular radar is found to have a weakness due to beam width/location.
Re the 2nd para, these are nebulous comments! Please provide some more data on this! How significant are these effects,vis-à-vis attenuation within 100km? What is the relationship between dewpoint depression and attenuation.
Yes, what you say is one explanation. Or might it just be that the storm that you chased, which produced no hail, no documented intense rainfall was a photogenic but ordinary thunderstorm. That is, the much maligned Yarrawonga radar was in fact depicting precipitation rates with acceptable accuracy. Surely this is a more parsimonious explanation?
Regarding the second point I draw to your attention the following from the official bureau information on doppler performance: Rapidly translating mesocyclones
John, yes, this is all common knowledge to chasers, so point out where the strong inbounds are (as opposed to a gustfront), which is what I would expect to see here. It appears that there are none.
Given the flow velocity on the day this is likely to mean that any mesocyclone is difficult to detect with full vertical doppler velocity, between lone minimum scan height as occurs in this situation.
Not sure what you saying here? I chased cells on May 10 that were racing @ > 100km / hour to the north-NE towards Tulsa. No problems with seeing mesos that day! Out course you will have asymmetric in- and out- bounds, but so what? Surely any difficulty in meso detection in this situation would ultimately relate to the strength of the storm circulation against the speed or propagation, yes?
Lets look at the position of our chase vehicle relative to the storm, we are relatively speaking behind and slightly in front of the curvature arc. There is no precipitation to our west, this is completely clear air (you would note the exposure increase). The storm is moving roughly south while we look SW.
Sure, but I’ll use Brad’s pics since they are time-stamped and there are more of them; just makes it easier.
Inflow above is curved in towards the storm from the NE vectors in the 1km layer (3919,3934,pic 1 from me).
[Surely, with your configuration, and a sth moving storm, your inflow at the sfc would be out of the east or south east?]. Also, I have posted a photo (see attachment below) from a broadly similar perspective, given the orientation you suggest, ie kind east of the flanking line and RFD; usually prefer to get much more east and closer in, but that was 1o years ago. btw, photo is flipped so as to appear as it would here.
The schematic of your positioning, which I’ve pasted on to the better diagram (again, see attachment below), clearly show that you should see a wall cloud (I am assuming that’s what you are thinking here with that cloud feature) and precip in behind that. That’s not what is in the picture below. Indeed, your ‘clean air’ is where I would expect the heaviest precip to occur. How can you explain this? If I flip my storm back to reality there would be more similarity than what we see below. This photo simply does not match up with your schematic.
The other thing I would point out is how exactly do you get a shelf with no precip/outflow behind it other than RFD, and to be orientated NE to SW with a lower section if the storm is moving S? It makes no sense, not to mention going against observation.
This happens all the time. I saw a nice shelf come right over my house a few weeks back, with nothing behind it. There was some thunder but the storm has bacially gusted out. You do have precip behind it in the first pic, so there’s the likely culprit.
This also displays the distinct curvature of a rotating updraft in a HP (that being precip outflow to the left of the tail which resides in front of this feature, and to the right also, however this may be a result of distortional correction confusing the issue, I will attempt to rectify this.
I really cant see this so will look forward to your rectification J
Finally I point out that the repeated blind faith in any supercell reported on the NSW east coast vs the heated questioning on any cell in the Southern Riverina/Victoria is utterly obvious on this forum, and speaks volumes towards the jealously over the seasonal performance of this area.
Seriously, we’re deviating here. My simple suggestion to you.....…is move up here! Australia is a big country. One would assume that supercells have occurred over much of the country. Year in, year out eastern Australia from about Sydney north to the sunshine coast and inland to Dubbo and up from there, is Australia’s version of the Great Plains. No one questions this. Other Vics, including Clyve and Jane who do these extended long haul chase expeditions regularly almost always end up in this broad region. Harald Richter posted something more detailed along these very same lines. You would also note that the strongest Australian tornadoes and the biggest hail reports have come from this region. Sydney and Brisbane, both in the ‘zone’ are the only two cities that regularly record giant hailstones within their metropolitan areas. That said, Southern NSW, Victoria and South Australia, and elsewhere, can get severe weather when the PBL moisture gets in; as has happened this season quite frequently.
I would like to point out that if NE-NSW really does take storms "to the next level" then it must have started particularly lowly given the poor record this season, and last season. Realistically your jaded views of the season should have no influence on your attitude to anything else. I wonder the reaction if the same disbelief and question was posted in every singe thread from there. Regardless of the bias, the supercell police need to remember that NSW does not own rights to it or its definition. If we are to continue this debate such disbelief and querying of moral integrity must be raised on every single storm claimed on this forum, not just those posted by myself and Brad.
haha, this is going way off in another direction. I will say that if this forum is home to the supercell police, I have heard whispers that you are the tornado governor J.
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btw, good to see more posts. For my part, I'll read them tomorrow since I intend to be pleasantly inebriated tonight. Remembering that insults are the first refuge of the ignorant, I really hope people from all corners of the discussion can debate the issue and not the person. Have not had a good discussion for a while and this is a good warm up with the US season only several months away :)
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This topic is locked. No further discussion will take place.
Regards,
Jimmy Deguara
Forum Moderator