Author Topic: VIC/NSW Severe Thunderstorms 27 - 28 February 2010  (Read 15900 times)

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Offline John Allen

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VIC/NSW Severe Thunderstorms 27 - 28 February 2010
« on: 28 February 2010, 11:48:22 AM »
Just had some very interesting observations from a chasing friend in North central Victoria, heres the radar loop from this morning to late this afternoon for Yarrawonga.

See :
See : 256km Radar Loop for Yarrawonga, 23:00 26/02/2010 to 09:00 27/02/2010 UTC


Obvious left mover formed near Heathcote, dies on Kyabrum. Very nice flying eagle structure, and very strong returns and good doppler returns for the later stage.

A right mover has formed to the west and is moving to the SE, its a split from the left mover moving N, west of Echuca.

Will continue to update.
« Last Edit: 28 February 2010, 03:58:44 PM by John Allen »
Explosive events coming to a weather system near you.

Offline Brad Hannon

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RE: VIC/NSW Severe Thunderstorms 27 - 28 February 2010
« Reply #1 on: 28 February 2010, 03:28:19 PM »
Impressive reports and pics coming in for this arvo's storms in the North Central region of the state.  Check out the pics from Rikki Pool at the top of pg14 - simply awesome  :evil: .  He is having one helluva season thats for sure!

http://www.theaustralianweatherforum.com/forum/viewtopic.php?f=16&t=206&p=9407#p9407

Update: Reports confirming tornado from this storm - video and photos taken but yet to be posted.
« Last Edit: 28 February 2010, 03:44:19 PM by Brad Hannon »
hmmm June 2nd......

Offline Michael Thomas

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RE: VIC/NSW Severe Thunderstorms 27 - 28 February 2010
« Reply #2 on: 28 February 2010, 05:03:29 PM »
Fantastic photos on that forum! Probably some of the best supercell structure I have seen this season. Really text book structure. The left mover was certainly the storm of the day. Interested about the tornado reports, looking forward to seeing the video. I don't find it hard to believe that the left mover produced a tornado based on what I have seen. As seen by the radar, the storm was a sharp left mover with no competition from other storms. Having a look at the surface obs, it seems that dew points were in the high teens (17-19C) with temps in the mid-20's so the LCL shouldn't of been too high. Finally, the photos show excellent structure. The earlier photos show what I believe is the RFD cutting in behind the base (4th photo is the best example). The last several photos then show a wall cloud almost scrapping the ground and you can see quite a bit of precipitation in the RFD making up what would have been a nice hook echo.

That is what I make it anyway. Others on this forum have far better knowledge than I do.

Michael

Offline Richary

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RE: VIC/NSW Severe Thunderstorms 27 - 28 February 2010
« Reply #3 on: 28 February 2010, 06:06:53 PM »
I noticed this storm on the radar as well. The Doppler wind plots from Yarrawonga certainly looked very interesting, I think it was the 0522 one that while showing most of the wind heading towards the radar had a very strong yellow spot right at the western edge of the storm that was west of Shepparton so certainly in the area. Rainfall intensity was very strong as well. It would be interesting to see some of the experts look at the doppler wind plots of this one.

Offline Brad Hannon

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RE: VIC/NSW Severe Thunderstorms 27 - 28 February 2010
« Reply #4 on: 28 February 2010, 06:38:50 PM »
It would be interesting to see some of the experts look at the doppler wind plots of this one.

Hi, I was hoping for some feedback/thoughts on exactly the same issue from the Avenel storm of 2 weeks ago which actually had 2 red returns on doppler wind!  ;)
hmmm June 2nd......

Offline James

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RE: VIC/NSW Severe Thunderstorms 27 - 28 February 2010
« Reply #5 on: 01 March 2010, 04:06:37 AM »
Wow! Now they are some impressive photos with some great classic supercell structure. Agree with MT, the photos show a classic example of a RFD (and clear slot). Probably up there as some of best storm structure photos I have seen from Australia this year. Head back home tonight so will have a look through radar and obs later.

Offline scottme

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RE: VIC/NSW Severe Thunderstorms 27 - 28 February 2010
« Reply #6 on: 01 March 2010, 08:41:43 AM »
There is a suspicious looking cell moving through Camden in Sydney now that is starting to show a v shape - possible supercell? Severe warning has just been issued at 14:32. A cell just exploded over Warragamba just to the northwest flank of the above storm.

The odd thing is, I can't really see much from in front due to the mist.

Offline Harley Pearman

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RE: VIC/NSW Severe Thunderstorms 27 - 28 February 2010
« Reply #7 on: 01 March 2010, 11:46:06 AM »
Some photos of the Sydney storm 28 February 2010

Below attached are three photos of the Sydney Storm. I am at Blacktown on Bungarribee Road. The storm moved in from the south west producing an interesting shelf cloud as well as new updraft towers and cloud formations.

As the shelf cloud passed over, a strong south to south west wind ensured for a period of time before easing. While interesting cloud formations were observed and photographed, no damaging weather occurred. The storm system did produce two bursts of light to moderate showers and thunder was audible for a period of time before waning.

Harley Pearman

Offline vrondes

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Re: VIC/NSW Severe Thunderstorms 27 - 28 February 2010
« Reply #8 on: 01 March 2010, 03:37:06 PM »
Good to see you get some captures of the leading edge of that storm this afternoon Harley. The underbelly of that shelf cloud displayed
some dramatic whalemouth features when I went out to a Golf driving range near Cowpasture rd and Horsley drive around 3pm.
. Nice dark clouds with filtered light coming through before rain and  cloud to cloud lightning with the odd cg took over.
Cheers, Con.






Offline Richary

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Re: VIC/NSW Severe Thunderstorms 27 - 28 February 2010
« Reply #9 on: 01 March 2010, 04:21:58 PM »
You guys a bit further west certainly got a better view of it than I did at Rydalmere. I had been up to Wyong during the day and on the drive home about 2pm could see some thunderheads way down to the south trying to be visible through the lower layers of clouds that generally blocked views from home.

As the storms were heading around Camden things were looking promising enough for me to set the lightning trigger up on the camera but after about Oatley it all seemed to fall apart in intensity. We ended up with a bit of thunder, 2 visible bolts and 6mm of rain. The shelf cloud was falling apart by the time it hit here with lots of outflow scud.

On other storms, the lower Blue Mountains looked like it might have copped a nice left mover, another formed near Bilpin later. There was also one near Mangrove Mountain that caused a severe alert for the Hunter but fell apart shortly after. And another one down south near Point Perpendicular that from the radar images I am surprised didn't get a severe warning with a nasty deep red line in it for a while.

Offline Harley Pearman

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Re: VIC/NSW Severe Thunderstorms 27 - 28 February 2010
« Reply #10 on: 02 March 2010, 12:51:53 AM »
Possible Funnel cloud photo (Blacktown 28/10/2010)

Further to my earlier post while watching the shelf cloud pass overhead, I captured this image attached. A new updraft tower seemed to develop just to my north. When watching it, I noted a formation under its base and it appears to be a funnel cloud however I seek clarification. However, I would be most happy to receive any comments on this. This formation lasted no more than 20 seconds and I watched it dissipate quite rapidly.

The photo is taken on a reserve off Bungarribee Road Blacktown and I am looking north although I have focused in on the subject. While it was projecting below the cloud I must stress it did not extend any lower. The subject is centre of the photo and I took every effort to ensure I placed the subjet to the centre for best viewing.


Harley Pearman

Offline Jimmy Deguara

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Re: VIC/NSW Severe Thunderstorms 27 - 28 February 2010
« Reply #11 on: 02 March 2010, 11:30:01 AM »
Hi Harley,

If I am mot mistaken, that is a base funnel - hard to tell but these are not too uncommon with rapid developing updrafts. Well spotted.

Regards,

Jimmy Deguara
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Offline pingtang

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Re: VIC/NSW Severe Thunderstorms 27 - 28 February 2010
« Reply #12 on: 02 March 2010, 12:08:33 PM »
My friend Andrew got onto a severe storm on the southern outskits of Nowra yesterday afternoon. There was plenty of leaf litter in a very localised area thanks to the 3-4cm hail. Strong winds and torrential rain were also a feature of this storm,with gusts of 87km/h and 2.4mms falling in a minute. The storm weakened somewhat as it crossed Nowra, but it somehow made it Gerringong but in a more elevated state. The storm had quite a strong base with nice inflow. A very nice storm!!!! Heres the link to the footage.

severestormnowra.wmv

Offline Jimmy Deguara

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Re: VIC/NSW Severe Thunderstorms 27 - 28 February 2010
« Reply #13 on: 02 March 2010, 11:55:46 PM »
Hi,

Andrew that is a nice cell - enjoyed the hailstones as well. I wished you had shown just a touch more timelapse of the base to see what was happening overall. I think you would need to have been a little more distant to get some perspective of what was happening to the structure. Love the hailstones though! Good storm event.

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Offline Macca

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Re: VIC/NSW Severe Thunderstorms 27 - 28 February 2010
« Reply #14 on: 03 March 2010, 03:13:59 PM »
Congrats to all who chased Saturday with some amazing photos across various forums which contain almost anything anyone could want on a chase (note the term almost).

There are some pretty nice hail photos (on another forum) showing 4-5cm hail with a wide spread cover of 2-3cm hail with those larger stones and more recently reports of much larger hail! Very nice indeed (I’m a hail fan so kudos to that particular chaser).

There are also some AWESOME structure photos showing near text book supercell structures (particularly the Echuca (?) storm from later). The updraft photos from Jane/Clyve are some of the best I’ve seen in a long time (from anywhere) and the radar imagery clearly shows strong left movement from the initial storm over north central Victoria. In fact I think these are probably the storm/s of the year/season for the whole of eastern Australia.

What I’m going to say now is no doubt going to make me more enemies than friends and I’m not posting this through jealousy (although I’m spewing I wasn’t there) or any sort of interstate rivalry (I’m a Victorian a heart although I now live in Queensland and still dislike NSW when it comes to sporting events).

I think there is some confusion about who has dubbed what a tornado and also some inconclusiveness as to whether and what is a tornado. This is in reference to the first storm (the earlier left mover).

In Rikki’s chase report, there are three photos which are described as being a tornado (“The speed in which was moving was very surprising and I had to get out of there quick smart. I am 100% sure that is a Tornado. No ladspouts, no Scud, a fully fledged tornado.”). This is a text book RFD and associated clear slot wrapping around a wall cloud which is hugging the ground. It is quite plausible that there was a tornado in/under that wall cloud and a damage assessment in this area would reveal whether/where a tornado occurred if this was the case (more on the damage assessment later).

http://i14.photobucket.com/albums/a318/rikjpool/storm2feb27th08_1.jpg

Slightly after this, there is the next series of photos/video grabs from Rikki and Jane/Clyve (and associated videos from Rikki which are both from this phase). These photos seem to be when the storm is in a weakening/outflow dominated phase – as was stated by Rikki in his chase report. I’m not sure if this dusty phase is what Jane and Clyve are referring to as the tornado that they saw – perhaps they could clarify? If so, the photos of the “tornado” don’t look quite right to me – the dust seems to be kicking up on the RFD outflow area as opposed to where the RFD is interacting with the updraft/inflow area. I’ve tried to put together a rudimentary diagram over the top of the imagery to depict what I mean – I hope this helps explain what I’m getting at here.

http://macca.bsch.au.com/gallery2/d/5642-1/270210jon385tv2.jpg

The video grab also doesn’t look quite right with the “funnel” appearing somewhat ragged. Nearly every example I’ve seen (in photos and personally) of tornadoes, the funnel has been a very sharply defined on its edges (due to the steady state of the near tornado environment). A very similar feature also appears to be in one of Rikki’s photos from a more “front on” angle – refer below again for more rudimentary drawings. Without seeing any motion, they both just look to be some interestingly shaped scud as opposed to a genuine funnel.

http://macca.bsch.au.com/gallery2/d/5647-2/2702corop01v.jpg

http://macca.bsch.au.com/gallery2/d/5652-2/storm2feb27th03_1.jpg

There is definitely clear evidence of a supercell and there is definitely clear evidence of a mesocyclone (both through Doppler radar imagery and through the photos provided) but there is no clear evidence that there is a tornado. Conditions were not unfavourable nor favourable for the development of tornadoes but without further video evidence showing rapid organised rotation or video/photographic evidence showing a more defined funnel, this would have to go down in my book as a “maybe”.

To further support this, the damage assessment done has revealed very little damage (although has potentially uncovered some massive hail). Shear was definitely adequate for supercells but tornadoes...I’m not so sure.

The early images posted by Rikki (first link above) are similar to plenty of supercells I’ve seen (again personally and in photos) from the USA which have produced tornadoes, but without someone being in there under that mess, it makes it hard to conclude. The later images are similar to plenty of supercells I’ve seen here in SEQ and in northern NSW (and southern NSW and Victoria for that matter) – outflow dominated but just not as much dust – probably due to not having been in a drought for 10 years.

Like I said at the start, this has/will probably make me more enemies than friends but I think its really important that this discussion takes place – for several reasons. Firstly to discuss and investigate and arrive at a conclusion as to what has happened here after taking out the emotion associated with such an awesome, high-paced chase, and secondly (and probably more importantly), to assist people who read the forum and aren’t able to chase (and even those who are) to better understand the dynamics associated with supercell thunderstorms and tornadoes. I’m happy to be shown more evidence that this was in fact a tornado (and looking at the structure – particularly of the Echuca cell – it probably deserves one) but until then, this/these tornado claims are a “maybe” in my book.

Again I want to re-iterate what I said at the start of my post – I think this is one of, if not THE best storm day/storms of the season for the whole of eastern Australia and no matter the outcome of this discussion, my opinion of that will not change.

Macca