Author Topic: NSW / SE Qld Severe Storms 7th - 9th October 2011  (Read 8539 times)

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Offline nmoir

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NSW / SE Qld Severe Storms 7th - 9th October 2011
« on: 09 October 2011, 08:40:49 AM »
Now thats an interesting radar signature ....hook echo people? its one of the last frames , after its gone off the coast

See : 128km Radar Loop for Gladstone, 04:00 07/10/2011 to 04:00 08/10/2011 UTC
« Last Edit: 09 October 2011, 08:46:57 AM by nmoir »
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Offline Michael Thomas

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RE: NSW / SE Qld Severe Storms 7th - 9th October 2011
« Reply #1 on: 10 October 2011, 03:56:39 AM »
Here's something I posted on the WZ forum-

"I think these were the storms of the day (though I am partial to a nice bow echo). Beautiful cell split south of Calliope with a nice strong left mover taking off. The left mover then merged with another cell to produce what looked like a pretty big HP supercell off Gladstone. This storm then transition into a bow echo near Heron Island. What a storm!

A few obs from Gladstone-
08/12:30pm 31.0/19.4 N 22 39 (wind speed average and gusts in km/hr)
08/12:00pm 31.4/17.7 NNW 15 30
08/11:30am 29.3/17.2 NNW 13 28
08/11:00am 29.3/19.6 NNW 19 35

They are some pretty decent obs considering 500 mbar temps were around -14 C at the time. Also, 500 mbar winds were around 45-50 knots from the WSW.

I have some photos from which I guess are of the storm that passed just west of Heron Is. It looked very strong from what I could see, big overshooting top, back sheared anvil (may post some photos later, not very interesting though). I wouldn't be suprised if that storm was dropping some bombs."

The scan at 11:40 am shows an interesting feature. The Gladstone radar unfortunately doesn't have the resolution of the newer doppler radars. To me that looks like a possible hook echo though.

Offline Jimmy Deguara

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RE: NSW / SE Qld Severe Storms 7th - 9th October 2011
« Reply #2 on: 10 October 2011, 12:50:12 PM »
Hi,

I am finding it difficult to know which frame is the one of interest? 11:40am?

It looks like to me there is an inflow notch and then the cold outflow pushes out with core closer to the foward flank. Would have had an impressive shelf cloud - very nice storm. Probably hailstones would have been at least 5 to 7 cm in diameter out there.

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Jimmy Deguara
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Offline Jimmy Deguara

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RE: NSW / SE Qld Severe Storms 7th - 9th October 2011
« Reply #3 on: 10 October 2011, 05:08:07 PM »
An upper trough was progged for some time to surge through the eastern states of NSW and across the border to south central Queensland coastline. On the 7th October, storms developed across the NSW coastline and south central Queensland. A storm went severe in the greater Sydney region. Overnight more storms developed including a band of severe storms that congealed into a major squall line in SE Qld including a HP supercell near Gladstone. A spectacular event!

Storm Chase 7th October 2011

I decided to remain in Sydney to watch storms that might develop locally. Given the windshear profile and particularly the lower 3km level shear between 06Z and 09Z was favourable for interesting lower level features.

One storm in particular developed over the eastern ranges with more cells developing closer to Penrith. This partiuclar cell eventually tracked northeast towards Colo Heights. I intercepted the cell near Windsor and then gradually found a position near Glossodia. The cell exhibited intersting base features and become more electrically active than most other cells. Very heavy rainfall fell from this cell that eventually collapsed to produce a cell along the forward flank that went severe.

Near Windsor


From Glossodia









Storm Chase 8th October 2011

Once again, I had decided to remain in Sydney for this event given the deep moisture had already built in the Sydney basin. As the morning wore on, a few showers developed around the Sydney basin. The cold air axis with -20C nearing Sydney/Wollongong was meant to pass over between 03 and 06Z (2pm to 5pm). Almost on cue, the atmosphere began to organise with a boundary between Camden and Penrith being the focus for the first main development. David C and I were in contact all morning and David once again alerted me to the Horsley Park cell developing. Another cell which was the one I was watching had developed near Blacktown within the unstable air environment. This cell had a sufficient rainfree base for me to position myself slightly closer. After brief stop near Quakers Hill, I headed into the storm to see if any hail may have been falling though mostly expecting heavy rain from this development. the heavy rain was in the region near Parklea and further east and south nearer Blacktown. Shortly after, I turned for home. The continuous build up of electrical activity towards the Rouse Hill area lured me to the storm once again. Interestingly, the rain was so focused that a creek separated the heavy rainfall from lighter rainfall.

It was chaos on Windsor Road. Cars were stopped along the side of the road. Suddenly a barrage of pea sized hailstones near the intersection of Windsor Road and Old Windsor road - lightning bolts could be observed through the rain core to the east. After making Castle Hill, I headed north along the Northern Road. David C and Nick Moir confirmed this decision. I was fully aware of the difficulty to photograph in this region but you forget just how many trees there were and of course it also depended on the direction. I eventually recalled one spot north of Dural where I coudl photograph the base structure. By this time it seemed the storm had either dumped heavy precipitation or from the core or redeveloped further north. This storm was once again into the marginally severe criteria but moreso multicellular in behaviour. After venturing up to Maroota, and a few more pictures of the shelf cloud/base, I finally photographed hailstones washed into piles on the side of the road near Maraylia.















Regards,

Jimmy Deguara
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Offline enak_12

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RE: NSW / SE Qld Severe Storms 7th - 9th October 2011
« Reply #4 on: 10 October 2011, 08:27:31 PM »
Driving home from a friends house tonight (9th Oct) I saw some lightning out to sea and so went down to the Jetty to investigate. There was a fairly lightning active storm off the coast making its way past Coffs after forming offshore of Nambucca. I took some shots for about half an hour on the beach, I love shooting storms at night with a bright moon, It makes for a brighter scene.



« Last Edit: 13 October 2011, 01:59:41 AM by Michael Bath »

Offline Michael Bath

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RE: NSW / SE Qld Severe Storms 7th - 9th October 2011
« Reply #5 on: 11 October 2011, 04:57:14 AM »
Hi,

Jason Paterson and I chased Saturday 7th Oct. The sky was very uninspiring when we left the Lismore area with high cloud persisting and not much to see at first. Temps didn't get too high either, perhaps to 23-24 as a max. Radar indicated some cells gathering on the ranges surrounding Grafton from S - SW -W so we headed there via the Summerland Way.

Weak activity was observed from Grafton before one cell started to dominate just south of town:




The storm passed through South Grafton and was heading slowly NNE at this point. We decided to brave the Pacific Highway traffic and drove into the storm. There were bursts of very heavy rain and strong winds. Some small hail just northeast of town before the sky darkened even more and hail to 2cm hit near Ulmarra. The winds were quite violent and most other vehicles had parked on the side of the road, including the usual dummies under large trees. The temp was now hovering around 14. We could see the leading edge of the storm but it took until nearly Maclean to get out of it.





This looking back near Tyndale:



The view from Chatsworth Island north of Maclean was pretty good. The storm was looking very outflow dominated with a whales-mouth type gust front







The storm was certainly moving quite fast now so we shot north to Woodburn. Despite travelling 35km north at 100km/h or so the storm was still almost on us at Woodburn:





The features here were still very nice. No hail at this point but some very heavy wind-blown rain.


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Offline Paul D

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RE: NSW / SE Qld Severe Storms 7th - 9th October 2011
« Reply #6 on: 11 October 2011, 03:34:14 PM »
Had a few commitments on the 8th but I managed to get out early and watch the main gust front cross the coast didn't encounter any severe conditions locally but the guster was photogenic





Paul D

Offline Harley Pearman

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RE: NSW / SE Qld Severe Storms 7th - 9th October 2011
« Reply #7 on: 12 October 2011, 02:00:30 PM »
Storm chase Saturday 8 October 2011

Its been a while since my last report but on Saturday, I also did a storm chase around Castle Hill to Windsor and north to the Wilberforce / Ebenezer area. I had worked out that storms would develop between 2 and 5 pm across Sydney Saturday afternoon. Just before 2 pm, I went to a lookout at Bella Vista where I saw the first storm develop over Blacktown. I soon discovered the storm was building over me so I had to hurry back to the car for shelter. I had planned to photograph lightning but never had the opportunity as the storm was too close.

I made it back to my car just in time as the storm broke with very heavy rain and cloud to ground lightning. I decided to head north west along Windsor Road where I found myself driving through very heavy rain and some outflow winds (SE Winds). Driving was treacherous and I saw people slowing down, stopping or trying to get out of the rain. I did see waterlogged creeks but did not encounter any hail fall. I broke clear of the storm around Rouse Hill. I drove to Windsor and then to Macquarie Park where I observed another storm building just to the NE of me.

I then proceeded to Wilberforce then Sackville and Ebenezer closing in on the second storm and stopping to take the ocassional photo of the cloud structure. I closed right in on that second storm which was by now dumping very heavy rain with the ocassional thunderclap heard. I watched a shelf cloud break free from the storm as it passed over me. The storm seemed to weaken and I stayed and watched the spectacle for a time to see what would happen. After a while, I left and returned home. I watched another cell to the west but I decided not to chase it along Putty Road because there are too few opportunities for photos.

I chose to go this way as I was after cloud structure and contrasts using my new Canon camera.

Jimmy, I read your report and noted that you encountered small hail near the corner of Windsor Road and Old Windsor Road. I was at that intersection for a short time during the event but did not observe any hail. Instead I encountered strong SE winds in that very area and some very heavy rain.

I only took a small number of photos but it is good to see storms in the Sydney region again.

Harley Pearman

Offline Richary

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RE: NSW / SE Qld Severe Storms 7th - 9th October 2011
« Reply #8 on: 12 October 2011, 05:19:53 PM »
I picked up the same storm as others on Saturday afternoon. I wasn't expecting a storm so hadn't taken the camera etc with me as we went up towards Seven Hills for some geocaching. As we got out of the car the thunder was getting closer and wind stronger so we decided standing in the bush wasn't the best idea.

We drove back to Baulkham Hills shopping centre where we had intended to be anyway afterwards and parked on the roof to get a view. Quite a lot of good lightning strikes were seen, with some rather close flangs as well. No hail at that spot but it certainly bucketed down quite heavily for a while. Looking at the radar track I thought it had missed home at Rydalmere but there was about 1mm in the guage and the cat had gone into hiding under the house so home must have caught the edge of it.

Offline Pete

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RE: NSW / SE Qld Severe Storms 7th - 9th October 2011
« Reply #9 on: 12 October 2011, 06:57:15 PM »
Now thats an interesting radar signature ....hook echo people? its one of the last frames , after its gone off the coast

See : 128km Radar Loop for Gladstone, 04:00 07/10/2011 to 04:00 08/10/2011 UTC


Looked to me like the radar was indicating rotation in that cell as it heads off the coast? Or is that just me?  :-\

Offline Jimmy Deguara

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Re: NSW / SE Qld Severe Storms 7th - 9th October 2011
« Reply #10 on: 13 October 2011, 02:48:18 AM »
Pete,

Rotation is one thing - hard to tell from radar but it looks like a supercell - "tailend charlie"! The question asked was there a hook echo - hard to tell from the resolution and type of radar but I think it was a nice HP supercell probably with a nice beaver tail off the coast in particular.

Regards,

Jimmy Deguara
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