NZ Geographic article on weather radar

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NZ Geographic article on weather radar

Unread post by Weather Watcher »

For those that are interested, the latest issue of NZ Geographic (Number 81, September-October) has an interesting article written by Erick Brenstrum on weather radar at MetService. The article has a few images from the upgraded radar system as well as a radar vertical cross-section through a supercell which brought large hail to South Canterbury in December 2001.
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Unread post by Storm Struck »

Will keep an eye out for it but a Supercell :? impossible we don't get them in New Zealand the land area's simply are not big enough.
Mesocyclones yes.
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Unread post by Willoughby »

Weather and impossible are never to be mixed! :twisted:

Would like to see the satellite from that day. There was a possible supercell east of Northland and Bay of Plenty not so long ago.

Thanks WW, must go and check that out. :)
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Unread post by Weather Watcher »

By definition, a supercell is a severe convective storm that possesses a deep, persistent mesocyclone.

Supercells can come in all sizes, and don't necessarily have to be the size of mid-west US storms and produce large tornadoes. Supercells are occasionally observed in NZ, and the hailstorm of South Canterbury on December 28 2001 was one of these.

There are many references on the internet defining a 'supercell'. Here are a couple...

http://www.cimms.ou.edu/~doswell/Confer ... rcell.html

http://en.wikipedia.org/wiki/Supercell

Also, take a look at the radar image in the NZ Geographic article. I think it's an impressive image. There is a very well defined Bounded Weak Echo Region (strong updraft), and a well defined seperate strong downdraft (hail shaft). Also, although there are no velocity images included the article, the radar did pick up a deep large scale rotation within the mid-levels of this storm (the mesocyclone).
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Unread post by Storm Struck »

Oh ok makes sense there must have been a tornado or several that day as supercells can well support tornadoes.
Perhaps few of those this year here and up north for you guys ;) only thing is hailstorms ruin crops so id need to know few days in advance so i can cover my vege's just incase :lol: and as Tony would say my hard helmet out :D .
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Unread post by Manukau heads obs »

as supercells can well support tornadoes.
sort of a bit wrong, in that.....
a supercell you can look at as a dominating thunderstorm, one big main convection area...others around it start to weaken...

and it will also be a mesocyclone (s?), and mesocyclones can spawn tornadoes

thats my understanding anyway (maybe wrong)
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Unread post by GraemeWi »

Would it be this one?

http://satellite.landcareresearch.co.nz ... d28121.txt

Looks like a large circular glaciated top?

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G
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Unread post by NZstorm »

I had a look back at the weather for that day. If it was a supercell it would have been the low topped type which are sometimes referred to as mini-supercells. The environment over Canterbury on that day was cold and a bit on the dry side.

Do we get classic supercells in NZ? There may have been a classic supercell in Southland last December. The day the farm was wiped out at Heddon Bush.
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Unread post by Thunder »

Ahh, something about this post reminds me of why I like the weather / mainly thunderstorms.

Will go out and get the issue. Looking forward to our first thunderstorm for the new season. Hopefully this darn NW flow settles down.

Ciao
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Unread post by C-Nimbus »

Foggy Hamilton wrote:Weather and impossible are never to be mixed! :twisted:

Would like to see the satellite from that day. There was a possible supercell east of Northland and Bay of Plenty not so long ago.

Thanks WW, must go and check that out. :)
was that the feb 14th one about 2 years ago?

if so i got some good full size piccies of that one, i think tho from memory that Steven just said it was a big, mature Cb and not a supercell as you need the rotation there (mesocyclone) to make it super.
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Unread post by NZstorm »

was that the feb 14th one about 2 years ago?
That would be the one. Feb 2004. It was fairly close to the Met Service radar at Leigh so the Met Service would have known wether it had rotation in it or not. I would liked to have got under that cloud. Hopefully there are some opportunities this summer to view cb's like that one. :)
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Unread post by C-Nimbus »

NZstorm wrote:
was that the feb 14th one about 2 years ago?
That would be the one. Feb 2004. It was fairly close to the Met Service radar at Leigh so the Met Service would have known wether it had rotation in it or not. I would liked to have got under that cloud. Hopefully there are some opportunities this summer to view cb's like that one. :)
its all gunna happen out west this year i reckon (convergence zones that is) :D so get ready for the re-birth of the Henderson Supercell :lol:

there you go, i've said it now :oops:
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Unread post by Weather Watcher »

Regarding the 28 December 2001 Supercell. The radar image in the NZ Geographic article was taken at about 2:30pm (NZDT, or 01:30 UTC). The NOAA satellite image in Graeme's link is listed as 2:47pm (assume NZDT?), so the large Cb top over South Canterbury in the satellite image is most likely the same storm.
Last edited by Weather Watcher on Tue 19/09/2006 15:56, edited 1 time in total.
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Unread post by Storm Struck »

Feb 14th was quite an unstable day and night indeed I remember having a thunderstorm go through about 5pm with heavy rain and close CG's went through rather quick though.
Then the Southerly eased and wind went back to the NE with unusual blanket of cumulus clouds sat around for about two hours getting darker and darker.
Next thing I know about 10pm i could hear thunder again and by heck that was a storm to remember.
Got the satelite image below.
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Jason.
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