Australian Severe Weather Forum

This report from the ABC quotes a BOM forecaster who said they had reports of hail to 20cm in size (yikes!). If that is true then surely is says something about the storm being highly organised and probably super-cellular?

Regards,
  Dave

Hail to 20cm i very much doubt, i believe as read on WZ that more like 20 cent piece sized hail. 20cm hail is unbelievably large...and would require far more powerful updrafts, together with perfect CAPE/Shear organisation for a LPstorm to generate. From the images presented by Jimmy im starting to have doubts about the validity of the storms existance as a supercell. The regenerating nature visible on radar agrees with Jimmy's assertion of a strong multicell.

Yes, 20 cm hail would require a special set of conditions indeed and, while probably not without precedent (largest I am aware of is around 19cm which fell in/around Aurora NE a few years back), would not occur with any of the storms in the environment we are talking about.

The hail report might have been logged by the same person as the tornado report (XXXX might have been the root cause), but more likely was just a misquote (ie 20mm).

David, your post above talks about some interesting scenarios and problems with warnings but little is said in regards to what you think about the validity of the tornado warning itself and reasoning.

I would not mind gathering your thoughts about whether you feel this is a supercell and also providing some reasoning be it radar or from a visual perspective.

Regards,

Jimmy Deguara

I saw this 20cm report too on wz , more chinese whispers i suspect , can you imagine the damage of 20cm hail on anything? dead cows etc and the hail would probably last to the next day , chasers would have shots of at least 10cm hail surely ,,

sorry to interrupt ,

go for it dave

Hi Jimmy,

The validity of a tornado warning comes down to the reasoning behind it being issued and to some extent whether it was verified, especially since this was based on a spotter report only. Remember tornado warnings are issued for 'landspouts' in the USA, so it is a separate issue to the storm being a supercells.

Regarding supercell:
I have no idea on what grounds these Queenslanders claim this storm to be such an obvious example of a supercell -- but it's not the first time and it wont be the last! Yes the storm tracked north but you will note other storms develop in this manner near Clifton at 8:30UTC and again near Glenelg following a storm split at 8:50UTC.

Looking at the radar loop the storm looks 'most' interesting from 6:30 through to 7:00UTC, although the visually unimpressive structure was apparently around this time too, ie according to the photo.  Well the echo seems rather discrete but that is only a 40 minute timeframe. There really is nothing to suggest that the storm is a supercell and this is only strengthened when you look at the  photograph at the time. That is all we have to go on!  Later on when the supposed 'meso' occurred (see photos) near Esk, the storm is a mess on radar and is clearly multicellular.

So, no I dont think the storm was a supercell based on available evidence and hence any 'tornado' was almost certainly not spawned by a mesocyclone.

Tornado:
One cannot rule out a 'landspout' and i would not be surprised at all if this is what was seen by the local spotter. Quite often when you have some boundary lurking favourably in the vicinity of updrafts/storms you will see landspouts in numbers (most recently in Orange a year or so back). Dalby is some distance way from Laidley (and looking at that storm might weel have been straightline winds) but this must be considered. I also found it funny how some of the storms developed in little arcs tracking NE, N and then NW over a few frames. There may have been something interesting going on, but we'll have to await the BoM analysis (if it is to exist) and also hope that a photo will come out of the woodwork.

Just reading the replies to this interesting event.  I was just wondering that even though the spotter reported 'seeing' a tornado, my query is this; with all the technical data and instruments etc that the BoM have at their disposal wouldn't the radar and sat pics indicate to them of such a pending storm?

 It seems from the postings that BoM was a little hasty in their issuing of a possible tornado?  Surely they just wouldn't post a warning like that if they weren't sure of its severity?  Or is it that there 'was a possibility' and they posted the warning anyway - which would seem okay by me as if i was a member of the public and there was the chance of something very severe, i would like to know about it beforehand.

I think it far better for the BoM to cover their butts - not for insurance reasons and not a knee jerk reaction to a spotters sighting (albeit true perhaps)  - but for a public responsibility to do so.    The bureau uses information that spotters give them as well as their own information, they're the experts aren't they? 

 If they got it 'wrong' well then many would be relieved - especially those people living in the affected area.  It's a two sided argument - better to err on the side of caution than have the storm pound some poor area and everone up in arms and sue the BoM for negligence for not issuing a warning of any sort at all!

 I can't comment on it too much due to lack of experience of such storms, but it just seemed to me odd that the BoM would issue this type of warning without some facts to back it up?

Mike :\

Hi Mike,

I concur to your that the Bureau had to act on the information and provide a warning. There are at least two factors to consider here: public liability and repsonsibility as compared to public confidence. The outcome thus far is that we, and I assume the rest of the public, did not see evidence of the tornado. So what has been done to public confidence? the warning was too general given we rarely get to observe tornadoes, forget about knowing the various types that could occur.

For instance, in a warning in the US a couple of years ago, the warning was put out for tornadoes. As the information unfolded, the warnings provided further desciptions about the short lived nature and the fact they were weaker as well as not necessarily occurring as normally anticipated with supercells. The warnings were eventually removed.

Regards,

Jimmy Deguara

Hi David,

Definitely one cannot rule out a landspout but my belief is that although there was a boundary in this case, it seemed that the boundary was not so tight. Also, I would have thought that landspouts tend to favour steep lapse rates - not sure what the case was here. I also think that boundaries become important in producing multiple instances of landspouts as you and I observed here:





For more check here 7 landspouts and 3 mesocyclonic tornadoes:
http://www.australiasevereweather.com/video/stills/2004/20040524.html

Regards,

Jimmy Deguara

Hi guys,

I quote Andrew MacDonald who wrote this on StormTrack


Say no more! Just another example of wishful thinking. Chasers or spotters that are hoping they were the ones to see the illusive tornadoes given our sparse population density!

Regards,

Jimmy Deguara

Can you follow up with Macca as to where this photo is located so we can all have a look ?

MB

Hi Michael,

You may have more luck tracking this down as I would say this person may be guarding it given the anticipated conversy that followed. David suggested that it may have been a chaser who made the report and would curl up afterwards.

Oh well, it is documented to have at the end of the all of the type of warnings that if a tornado is sighted, that a tornado warning will be issued - well this was in the days when I attended my last spotter training session which was quite a few years ago. Hell, I have been a storm spotter since February 1989!

Regards,

Jimmy Deguara

Storm Track thread
http://www.stormtrack.org/forum/showthread.php?t=10801

I have spoken to Macca about this and the photo in question is by Chrissy. I have the whole sequence of photos by Chrissy that she emailed, and at the time I thought scudy hailstorm look. She has not claimed any sighting of a tornado.

Some comments sent to me by Macca: "The only thing in the image I sent you that *could* be something is there is a lowering in behind a rain curtain.  There is a very small chance this could be a rain-wrapped wall cloud which could've been where the tornado was and that would've prevented Chrissy et al. from seeing it.  But as you mentioned, conditions were not favourable for tornadoes really so I have doubts about the above. "

The pic Macca saw had been enhanced to make it look meaner:

I feel it is time for BOM to start to take responsibility. We are constantly bombarded with many people in the public thinking  "we don't get tornadoes in Australia", TV reports are "it was like a Mini Tornado", etc etc. Never admitting it was a tornado, even when someone has captured the funnel and a touch down on video and it is played on the news only to disappear from further viewing. I strongly feel the problem lies with the fact that they will have to admit they needed to take the responsibility for the lack of education and communication between the public and the authorities involved as to the severity and intensity of the storms and the fact that we are frequently hit with tornadoes.

There is the issue of our building code and standards as regard to homes and buildings to withstand these storms, and more importantly the fact that our homes are not constructed with storm shelters. I am a builder, and the relevant costs to bomb or storm proof your laundry area (enough room for a family) is minimal  in comparison with the other changes taking place with our energy efficient/ sustainable housing programme. Interesting though after the Nov 16th storm, The CYCLONE TESTING STATION School of Engineering, James Cook University, Townsville  did an Investigation of performance of housing, in Brisbane, following the storms of 16 and 19 November 2008. There is rumoured that changes have to, and will take place.

(I found it amazing that approx. 1990 our cyclonic wind rating was changed from North of King ST. Caboolture QLd to around the Rockhampton QLD area.
Someone has the power to tell a cyclone it is no longer allowed to pass Rockhampton. Therefore this led to our tie down method being downgraded. What a mistake.)

Then you have the argument that it was not a tornado but a Micro burst, It was amazing that no one lost there lives in that storm of Nov 16th 2008. Honestly sit down and look at the many hundreds of pictures and see how many houses were severely or completely destroyed by a micro burst.

Whether it be a Microburst or tornado is relevant, when in fact, either has the potential to take many lives. A warning system needs to be put in place, maybe even a siren system similiar to USA. Most people take the storms here in Brisbane so casually, thinking nothing will happen to me. Then they are horrified after it hit, and how lucky they were to survive.

An education on the part of BOM and the public has to start, there has to be an education that there will be false alarms, an education that mistake will be made, an education that storms are unpredictable but take the precautions necessary and an education of what people need to do to protect themselves where ever they may be at the time of the storm.

Storms are gaining strength, but an attitude of "she will be right mate" may just costs many lives.

It is a serious Question and important one. Someone has to start the ball rolling. I am trying my bit, but with the information and pictures people associated with this forum have, and their knowledge of storms, could it start here, whether it is a microburst, a tornado or severe weather pattern etc.

Saving lives is important. Our climate is changing or shifting, who really knows what we are in for. The movie "The day after tomorrow" , 2 disc version has some very important documentaries to the movie, intersting viewing.

Cheers.

All I've read thus far on this subject certainly makes sense to me and regrettably we have many, many people out there who don't take the technical or scientific attitude to chasing to gather information so that we, as chasers, can relay the information back to BoM so they can correlate all this info. 

Do BoM simply take it as a given that when they receive a report of something severe or tornadic from someone 'out taking photos and claiming to be a storm chaser' thus giving them very bad information that leads to knee-jerk advisories?  The liability subject has been covered and BoM has that responsibility naturally for all our safety in mind, but what really angers me are those that repeatedly call up BoM during their 'localized chase' and having no experience / knowledge of storm structure during its lifecycle and blurting to all and sundry that storms are this or that when in fact they are not.  Indeed, with supercells - there's no way I would attempt to report anything supercellular here or interstate because I just have not seen them regularly enough to determine what makes a supercell!  People up here always report severe storms as 'rotating and appearing supercellular in structure' and that's just a blatant, outright lie!

I agree with Nick that perhaps there should be some type of educational tool available that gets to the 'essence' of what is deemed tornadic with supercells here in this country.  But whilst there are those of us that take chasing seriously (whilst enjoying the ride) and gathering data for feedback to BoM and actually taking photos of the severe indices of a thunderstorm, the number of rednecks screaming around claiming to be chasers may impact on who BoM takes seriously!  Just because a person is a BoM storm spotter says nothing about their experience - perhaps they should give an online test to anyone wishing to become a serious spotter so it eliminates or weeds out the radar chasers, at least that way they would have a pool of names which they can confidently rely on as giving correct information and adjust their advisories accordingly.

We see it all the time on other forums - continually giving misinterpretations and bad observations to BoM and others and this has a domino effect though the ranks and makes it extremely difficult for seasoned, experienced chasers to argue their point across. The numbers are against us but all we can do is try and formulate something with the bureau to co-join forces when relying on accurate observations whilst out in the field - how do we do this - well, meeting with BoM senior forecasters for a start i suspect and brain storming issues?

With all these storm chasing docos on the television it's no wonder there's so many out there destroying all the previous good work that serious chasers have accomplished and we're continually having to argue and correct misinformation to others because 'they heard this and that and well, I 'chased' a storm and it showed blah, blah, blah'

I shake my head in frustration continually - it's an epidemic I see every day up here also.

On BoM's time management for damage assessment issues:  I agree that they should take the time to go out to these reported sighting locations and check for themselves to confirm that phoned in report of a tornado. It's no use waiting weeks later when it's all been cleaned up because you need the 'signature' from the tornado or microburst - it's forensics people!  And I pooh, pooh those that claim to be chasers yet don't provide any photographic or video evidence so that at least it can be dissected by BoM for analysis - we can't always get to the exact location, but we certainly can take multiple shots to at least show progression of a severe storm.  Don't BoM view images people send them (from credible chasers) and then assess the obs and soundings to determine what went on?

Even with my tornado here - BoM have not even bothered to send out an observer or part time officer to check the area.  If I had a GPS I would at least get the coordinates from the radar loop of that storm in Humpty Doo and trudge through the bush with it until I found the area - at least I'd find any damage or nothing to confirm what I photographed and reported!!!  I can see the checklist of severe storms in this year's spotters newsletter...'Tornado sighted Humpty Doo'  and that would be it.

I think I'll go out and borrow a GPS, at least I'll get something before it all gets burnt away from fires or another gusty storm which would obliterate my tornado signature....

A bit long winded but I hope my thoughts are agreed to in some way.  Cheers all.