Author Topic: NSW and VIC supercells 12th & 13th Jan 2011  (Read 23600 times)

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Offline Brad Hannon

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Re: NSW and VIC supercells 12th & 13th Jan 2011
« Reply #30 on: 22 January 2011, 06:52:30 AM »
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.
hmmm June 2nd......

Offline David C

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Re: NSW and VIC supercells 12th & 13th Jan 2011
« Reply #31 on: 22 January 2011, 07:46:06 AM »
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.

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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. 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?

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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.

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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?

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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.

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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.

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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.

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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

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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.

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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.
« Last Edit: 22 January 2011, 08:01:52 AM by David C »
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Offline David C

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Re: NSW and VIC supercells 12th & 13th Jan 2011
« Reply #32 on: 22 January 2011, 07:55:39 AM »
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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Offline Jimmy Deguara

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Re: NSW and VIC supercells 12th & 13th Jan 2011
« Reply #33 on: 22 January 2011, 04:19:05 PM »
This topic is locked. No further discussion will take place.

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Jimmy Deguara
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