Thunder/Hail Storms for Sth Is. - Sunday, Mar 25

[Lacertae]

Looking at the radar sequence I would expect Southbridge or a spot a bit closer to the Rakaia for funnel activity, especially around 16:22/16:30 ...

[Thunder]

Thanks for those radar images Nev, does look some hail in there for sure. Dam should've followed it.

Thankyou for the clarification Brian.

[mikestormchaser]

Interesting to read those posts, here a few of my pics i thought id share, although not as good as Aarons, still something

[NZ Thunderstorm Soc]

Here's from this morning's Christchurch's THE PRESS from Paul Gorman.

Experts not sure tornado occurred
By Paul Gorman - The Press
Last updated 05:00 27/03/2012

Was it or wasn't it a tornado that hit Leeston on Sunday afternoon? Storm chasers and weather watchers are still not sure exactly what brought down trees in the area about 4.30pm that day.

A line of thunderstorms developed and moved across central and South Canterbury with a southerly wind change on Sunday afternoon, bringing heavy rain, high winds and hail up to 15 millimetres in diameter. The clouds then passed out to sea to the east of Banks Peninsula, missing Christchurch and North Canterbury.

Leeston farmer Alan Manhire said extreme winds brought down a large willow tree, snapped branches and threw them 50 metres, and seemed about to overturn his car. He estimated the winds, which died down after three minutes, reached 200 kilometres an hour, while MetService forecaster Hordur Thordarson thought there could have been gusts of up to 100kmh.

Christchurch storm chaser Aaron Wilkinson tracked and photographed the thunder clouds across the Canterbury Plains. He could not be sure the spectacular formation over Leeston that caused the damage was a tornado rather than a squall line, he said. "[We] really need someone to say they saw the actual funnel and all. Hopefully someone did and a report comes in soon," he said. "I was out chasing and got the storm just south of Ashburton. "It moved north and we figured we wouldn't be able to catch it as initially it seemed to move fast. It seemed to stall a little as it moved north, then moved east slowly offshore." During the evening he experienced gale-force or stronger winds from the cloud at Birdlings Flat.

MetService spokesman Dan Corbett said a tornado could have occurred, but a squall line could bring winds of a similar strength. Radar images had shown "a couple of hook echoes" suggestive of tornado activity, but there had been no reports of a funnel. The atmospheric conditions had been right for tornados, with cold temperatures aloft and winds from different directions at different heights, Corbett said.

© 2012 Fairfax New Zealand Limited

Source: http://www.stuff.co.nz/the-press/news/6 ... o-occurred

[mikestormchaser]

Yes i saw that!! lucky Aaron again getting into the paper!! good stuff man! i do still do feel proud of standing right next to you Aaron when u took that photo lol

[Storm Struck]

I actually found out i know the guy who's farm was hit so ill get in contact with him and find out what he really seen, he does tend to exagerate abit i think one of those people who has a batch in the far high country where he goes to stay for roughly 2 months then comes back out east again for more part time work.
Very efficient saved money grows alot of his own food etc, but his batch is a second retreat should further quakes or a tsunami so he thinks swamp the plains .
So i think the 200kmh is certainly over estimated, if winds were that strong we would be looking at a supercell status which would have covered much of the canterbury region including christchurch and even thats very rare.
We can get a smaller but simular form to a supercell but its very rare more so a mesocyclonic storm like 27th october 2002 when several tornado's touched down that day with golf ball hail.

[mikestormchaser]

Hmm I think we could get a supercell here, everything would need to be absolutly spot on with conditions but it could happen, Yes that meso storm in oct 2002 was an absolute beauty!! remember it well and John gaul chasing up on the port hills in mr morris

[Storm Struck]

I had a chat with his Mrs he seems to think it came through when there was alot of heavy hail so it sounds like a local squall line or downburst perhaps gusting over 100kmh briefly.
Uploaded a video to you tube of the hail we encountered west of Ashburton, no lightning as it was behind us but thats because of the precip and hail falling at the time made it hard to film without getting the camera wet.
Still you get an idea for the hail size and the rumbling thunder.
http://www.youtube.com/watch?v=Zk02YuTz ... e=youtu.be

[NZstorm]

Thanks for the you tube clip, great to see the hail storm!

The radar images point to a squall type set up with a SE running into a NW. The hail echoes look to be on the inland side of the precip suggesting its the warmer NW thats providing the instability, in which case it certainly couldn't be a tornado.

[Lacertae]

Is your video from the main cell or the one just before we caught up ?

[Storm Struck]

It was from the first main cell Lacertae filmed as it passed overhead, i think we caught the hail core edge to the west but were just far enough east to be in the action.
To note there was no real surface NW that day however we did come across a NWer when we stopped in Rolleston on the way south as it was Easterly back in Christchurch.
Elsewhere was E-SE winds and southerly with the isolated cells, but the wind in the upper levels would have certainly been NW.

[Orion]

Neat video, thanks, Jason.

[mikestormchaser]

Great video jase!! alot better then my clip, although i need more practive filming with time and the excitement really gets to me lol.

[Thunder]

I'll really have to set you guys up next time to get the best out of your videos, I've still got to give you some good basic storm educations Mike which we'll do soon! Promise. Mind you my video hasn't been the best recently trying to operate it and a digital camera at the same time, I need another tripod for the video camera or to pick and choose more when I do one or the other.

Interesting that with these new HD cmos video cameras when lightning flashes the sudden change in brightness causes all this horizontal banding on the image which I find unfavourable, especially at night. Where'as my older CCD video camera videos lightning perfectly but just not as good quality, with video however perhaps I feel the quality isn't a major aspect unless it's really bad, more I'm interested in what is happening in the video itself. Still, a nice new video camera would be good!

Good to get that info on the storm Jase, does indeed sound like it wasn't a tornado. Surely would have been great to experience that down draft though!

Cheers
Aaron

[Lacertae]

It's possible the size of the pixels on your old CCD is bigger than on your new CMOS, meaning you won't get blooming so easily. Or the default quality/sensitivity of more recent sensors induce blooming more often ?

[03Stormchaser]

20120325_isb01.jpg

Offshore Lightning

20120325_isb02.jpg

Storm front approaching

Video still to come

[spwill]

Nice shots there

[03Stormchaser]

Full report up here now:
http://www.stormchasers.co.nz/fastpage/ ... x/1/link/1