Author Topic: NSW Coastal Rain Event (incl Lennox Head tornado) : 2-5 June 2010  (Read 21907 times)

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Offline Mathew Townsend

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RE: NSW Coastal Rain Event (incl Lennox Head tornado) : 2-5 June 2010
« Reply #15 on: 04 June 2010, 02:58:43 PM »
Some more astonishing footage from Lennox Head from NBN news (apologies if someone has posted this already haven't looked through all the pages). Truly an amazing sight and its a miracle that no-one was killed given the destruction.

http://www.nbntv.com.au/index.php/2010/06/03/lennox-head-tornado/

Click on the video player to view

Do you mind have that as on youtube? Im having trouble downloading it off NBN website because the picture tends to freeze.

Offline Harley Pearman

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RE: NSW Coastal Rain Event (incl Lennox Head tornado) : 2-5 June 2010
« Reply #16 on: 05 June 2010, 03:03:42 PM »
Sydney's Rainfall for 4 June 2010

Further to Troy's post, Sydney has had some significant rainfall including some local flash flooding especially across Sydney's East and North. Up until 9 am, some rainfall totals exceeded 60 mm. Even in some western suburban areas, rainfall totals were quite significant. The Bureau of Meteorology rainfall plot for Sydney till 9 am for 4/6/2010 is attached below. Since 9 am, further significant rainfalls have occurred and cumulative falls in some areas exceed 100 mm.

This morning 4/6/2010, I decided to drive to Bathurst and take a look at the weather west of the Blue Mountains. Interestingly the eastern slopes of the Blue Mountains has also had significant rainfalls and water has ponded in many areas along roadsides and significant runoff was evident. I found that the downpours are not penetrating west of Mt Lambie. The weather was fine and partly cloudy in Bathurst and clear sunny conditions prevailed further west. Driving back to Sydney, I experienced increasing low cloud around Mt Lambie, then drizzle at Lithgow, light rain and low cloud at Katoomba and moderate to heavy rain and showers descending the Blue Mountains to Penrith and heavy rain by the time I reached Parramatta at around 4 pm.

The heavy downpours / flash flooding scenes and severe weather is not penetrating too far west of the Blue Mountains. A range of weather features associated with the east coast low was evident through this 170 km cross section I did.  


Harley Pearman
« Last Edit: 06 June 2010, 12:41:52 AM by Harley Pearman »

Offline Richary

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RE: NSW Coastal Rain Event (incl Lennox Head tornado) : 2-5 June 2010
« Reply #17 on: 05 June 2010, 04:16:57 PM »
I spent the morning in the office at Chatswood, before heading to the eastern suburbs in the afternoon. Some very heavy but brief downpours for most of the day, with 61mm recorded since 9am at Observatory Hill.

News reports tonight indicated another tornado (obviously still getting over yesterday) that was almost certainly a waterspout that crossed the coast at Bronte severely damaging one house (roof ripped off) with no other damage in the area, though 10 reported it had also caused damage at Maroubra - but that could have been a separate event and they had no pictures backing up the damage reports there.

There was no lightning activity anywhere near Sydney on stormtracker that I saw, and the wind/rain radar obs showed nothing out of the ordinary that would have been a supercell to give rise to an actual tornado.

Offline Harley Pearman

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RE: NSW Coastal Rain Event (incl Lennox Head tornado) : 2-5 June 2010
« Reply #18 on: 06 June 2010, 12:59:32 AM »
Sydney's Rainfall for 5/6/2010

Sydney's rainfall for 5 June 2010, is consistent with the cross section drive I did from Bathurst to Parramatta on 4/6/2010. Light falls observed in far western Sydney to quite heavy falls east of Blacktown to the coast as shown in the rainfall plot for 5/6/2010 (BOM 5/6/2010).

Only 8 mm at Penrith to 73 mm at Hornsby 70 mm at Terrey Hills, 61 mm at Sydney Observatory Hill and 42 mm at North Parramtta which is where I finished my drive. This morning the rain and showers have eased considerably.

Richary, I was aware of another report of wind damage and flood damage in Sydney's east because I was listening to Radio Station 95.3FM there and back so I knew what was happening. This is the first time, I have driven a cross section of an east coast low from its outer edge back into Sydney and it makes driving quite interesting at times.


Harley Pearman

Offline Michael Bath

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Re: NSW Coastal Rain Event (incl Lennox Head tornado) : 2-5 June 2010
« Reply #19 on: 06 June 2010, 03:18:14 AM »
Another clip of the Lennox Head tornado

Lennox Head Tornado - Exclusive Footage Only On 7

Attached are the Brisbane soundings, obviously they don't show the low level shear in place at Lennox Head but the rest of the profile is ideal for thunderstorms.

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Offline Mathew Townsend

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Re: NSW Coastal Rain Event (incl Lennox Head tornado) : 2-5 June 2010
« Reply #20 on: 06 June 2010, 04:29:56 AM »
Wow thanks MB, that is so awesome video clip. Certainly EF2 rated nado. Cant believe so much debris in sky!

Offline Michael Thomas

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Re: NSW Coastal Rain Event (incl Lennox Head tornado) : 2-5 June 2010
« Reply #21 on: 06 June 2010, 05:35:32 PM »
John,

I did not suggest that the Lennox Head tornado was a ‘cold core tornado.’ The author of the paper put a link to even mentions that the term ‘cold core tornadoes’ is a bit problematic-

http://davieswx.blogspot.com/2010/03/cold-core-discussion-and-comments-38.html

I agree with you that this event is not a typical cold-season tornado. These typically occur (as you know) in SW WA and southern SA in association with strong mid-latitude lows. Here I would suspect 500 mbar winds to be in the 50 to 70 knot range and 850 mbar winds to be also very strong (30 knot + ???).  I am not too familiar with the conditions for these typical cold-season tornadoes so I will leave it at that. I did look up the paper by Kounkou et al 2009 and they did discuss these conditions in detail.

I will agree that there are difficulties in determining actual CAPE in the absence of a real sounding. I still believe that surface-based CAPE was safely below 1000 j/kg. The T/Td was only 18/15 in the general area which is very low. Plotting these values in Brisbane sounding only gives a CAPE of 460 j/kg. I am inclined to believe CAPE was much higher than this since due to the slightly warmer mid-level temps at Brisbane compared to Lennox Head. By replotting a model-derived sounding with 18/15 I get a surface-based CAPE of 870 j/kg. This probably is not very accurate but I think a sbCAPE of 870 +/- 100 j/kg should be fair enough. Given the conditions though, this is actually not too bad.

Regarding the hail production, certainly the storm was an example of deep, moist convection. There was never any doubt of this in my mind. I would think though that the hail was generally quite small. I did hear a report of hail of ‘marble size’ which I would guess is referring to hail around the 1-2 cm mark. Due to the relatively low CAPE, I would be surprised if this storm produced large hail (say greater than 3 or 4 cm).

Finally, I am interested that you believe the tornado was the result of a shear dominated tornadic environment. I cannot see the evidence for this. 500 mbar winds at the location of the tornado were only 20 knots and 700 mbar winds were almost dead calm (2-3 knots) according to GFS. Admittedly, these values are from a computer model and are therefore not absolute truths. Looking at the Brisbane sounding, 500 mbar winds were 30 knots whereas GFS had them at 20-25 knots so it is possible that the wind speed at 500 mbar was slightly greater than 20 knots. At the surface there was an easterly at 20-30 km/hr (at Byron Bay anyway) so I would say 0-6 km shear was at best 40 knots. This a far cry from the conditions often seen in the US in early spring where you may have a 50-70 knots low-level jet being overrun by a 60-80 knot mid-level jet.

I believe that the tornado at Lennox Head was largely the result of favourable surface boundaries. To the south of Lennox Head there was a mass of non-severe convection which may of resulted in the formation of an outflow boundary orientated E-W. Drier air wrapping around the surface low would have formed a boundary of some sort running roughly N-S. The storm may have formed on the intersection of these two boundaries. Clear skies to the north of the rain to the south of Lennox Head would have allowed for at least some surface heating steeping low-level lapses rates. In addition, being so close to ocean probably also provided some heat (no morning inversion as may be expected at 7:30 am). Despite, the low temperature and dew point, instability was sufficient due to the cold temperatures aloft (courtesy of the 500 mbar low).

This a bit more detailed than I wanted to go into, or should go into for that matter. As always, if I am wrong please say so. This is a discussion forum after all. We are all here to learn, the weather is always doing things that we don’t always quite expect.

BTW According to the Kounkou paper, a tornado occurred on the NSW east coast which I am guessing is case 24 which occurred on the 25/7/2001 (http://soundings.bsch.au.com/skew-t.html?source=wyoming&lat=-32.7939&lon=151.8386&gribdate=&month=07&day=25&year=2001&hour=00&window=on). This may have been a similar setup as the Lennox Head event. Interestingly, the authors do note “To diagnose suitable environments for the other (eastern) regions, it was found that thresholds had to be set at very low values – considerably lower than for WA and SA (Kounkou et al., 2007). This appears due to the fact that the CST (cold season tornadoes) in this region is frequently associated with weather systems which have a small lateral scale.”

Michael

Offline Michael Thomas

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Re: NSW Coastal Rain Event (incl Lennox Head tornado) : 2-5 June 2010
« Reply #22 on: 07 June 2010, 10:21:18 AM »
Hi John,

Thanks, that clears things up very nicely. A bit of misunderstanding on my part. Might have to read about Mesoscale Convective Vortexes because honestly I know nothing about these.

Michael

Offline Jimmy Deguara

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Re: NSW Coastal Rain Event (incl Lennox Head tornado) : 2-5 June 2010
« Reply #23 on: 11 June 2010, 02:42:31 AM »
Hi,

Me thinks that the damage looks high end F1 low end F2 damage. You look closely at the damage, large less supported roofs as well as regions where verandahs allowing for leverage of front structures.

I don't believe this to be your atypical waterspout making landfall - it looks to have had a mesocyclone and merely by its behaviour of a tight vortex.

There was a similar type scenario a few years back where a tornado touched down over water and remained there off Newcastle, NSW and in the same shot, another waterspout was observed. You could see the difference in vortex structure.

Anyway, very interesting debris in the footage clearly shot by somoene in position other than a chaser. Not bad for early in the morning.

Regards,

Jimmy Deguara
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Offline Mathew Townsend

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Re: NSW Coastal Rain Event (incl Lennox Head tornado) : 2-5 June 2010
« Reply #24 on: 11 June 2010, 10:28:55 AM »
Lennox Head needs help


 JOHN and Heike Murray, along with their two children, are homeless.


But the Lennox Head family is not alone – there are 31 people who are without a home after last Thursday’s tornado which ripped through Lennox Head.


Six families have been put out of their homes by the storm.


And now the Ballina Shire community can do its bit to help those victims of the violent winds by donating to an appeal set up by the Lennox Head Chamber of Commerce.


As of Tuesday afternoon, the appeal had raised $12,000 for the victims of the tornado.


President of the chamber, Louise Owen, said ‘reality was sinking in’ for the Lennox community, and praised the community for coming together to support each other.


Mr Murray, standing outside his home of 15 years as workers in protective suits cleaned up asbestos, said it was a time to take stock and look to the future.


On a short-term basis, that means finding rental accommodation, and salvaging what belongings they can from their insured home, which had its roof ripped apart during the tornado.


He said the family wanted to stay in Lennox so schooling for 10-year-old Yani and eight-year-old Hannah wasn’t disrupted.


But the shock of the events last week, he said, meant they will be trying to live away from the area affected worst by the storm.


For the longer term, it’s a matter of waiting for the building assessors to check the home, and then look at rebuilding.


Mr Murray was away working at the time of the storm, but said his wife, Heike, had to throw herself over their two children to protect them when the storm – which sounded like a jet – tore its way through the northern part of Lennox Head.


The couple hasn’t been able to get back into their house to get clothes and other belongings since the storm – Heike, Yani and Hannah left with what they were wearing.


Mr Murray said he has been overwhelmed by the support of neighbours since, and also the Steiner community in Byron Bay.


They have had offers of accommodation as well as donations of food and clothing.


The family is currently staying in Ballina at the Ramada Hotel and Suites.


Ms Owen said Lennox Head as a community was now looking to the future – and the village is open for business and keen to get visitors back into town.


There will be some high-profile visitors coming this week.


The NSW State of Origin rugby league team will be visiting the Lennox Point Hotel for an autograph session from 5.30pm today, June 10.


And Fatty Vautin and The Footy Show team will be pre-recording the popular Channel Nine show at the pub from 6.30pm tonight as well, and it will air at 9.30pm tonight.


The event will kick off from 5pm.


The Lennox Head Lions Club members will be passing a donation bucket around to go to the Lennox Head Tornado Appeal.


Byron Street and Pacific Parade will be closed as punters gather at the park across the road from the pub for the event.


There will be specific areas for victims of the tornado and the volunteers who helped them, and those attending are asked to respect those areas.


The All Girls Surf Showdown on June 12 will take locals back to the beach at Lennox to catch some up-and-coming surfing talent.


And on Monday, June 14, there will be a community barbecue from 2.30pm across from the Lennox Point Hotel.


There will be a fundraising auction with local businesses donating vouchers, The Footy Show team will be bringing autographed footy jumpers, there is a soccer ball signed by the Matildas and a pumpkin is the novelty auction item.


Lions club members will be turning the snags.


To donate to the Lennox Head Tornado Appeal, deposit into Southern Cross Credit Union account: BSB 802185, Account Number 137897.

They have recorded that 150km/hr winds damaged the caravan park but winds may have exceeded 250km/hr inside the tornado.

Offline enak_12

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Re: NSW Coastal Rain Event (incl Lennox Head tornado) : 2-5 June 2010
« Reply #25 on: 11 June 2010, 12:55:27 PM »
Hi guys this was quite an event! I got sent some photos from my girlfriend who was sent them by a friend of her dads. Im not sure if this guy took the photos or not but I wanted to post them as I havent seen them anywhere else online. They seem to show a clear slot and satelite tornado.

Note these photos aren't mine..