'Bomb' low crossing North Island Saturday 3 March

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Richard
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Re: Deep low crossing North Island Saturday 3 March

Unread post by Richard »

:-k yer good reading alright,interesting the part where he says:
The low south of Patea came ashore east of Wanganui and then decayed, while the “new” low continued to deepen and move away to the east. This decay/development happens because the “driving” atmospheric processes are largely above the Earth’s surface and moving with the general flow: they left the Patea low behind and powered the development of the “new” low east of the North Island.
Mod Edit: Tidied up quote from MetSevice Blog linked in preceding post.
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Re: Deep low crossing North Island Saturday 3 March

Unread post by jamie »

Yes that is a good read.

It also answers why i thought the low had stopped moving when i was looking at the radar. So im glad to have worked that one out.

Now what did the wind get to? the highest ive seen was the 122km in the MS blog. Shame the power went out and recording stopped. I would love to know what the max average wind and max gust was for about 6am in that area.
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Re: Deep low crossing North Island Saturday 3 March

Unread post by NZstorm »

500mb wind chart here (colours) for midnight Friday with surface pressure. 12Z 00hr.

The low developed on the nose of the upper level jet stream. As air exits the jet stream it spreads out (divergence) which causes the air underneath to rise, which leads to pressure falls at the surface.

The jet strength at 500mbs was 100kts which is exceptionally strong for that height.
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Re: 'Bomb' low crossing North Island Saturday 3 March

Unread post by Nev »

A little belated but, thought it might pay to change the thread-title for future ref.

Highest gusts I can find are, 157 km/h at Brothers Island in Cook Strait, 154 km/h at Mt Kaukau in Wgtn and 141 km/h at Castlepoint in the Wairarapa.

There was a media report of gusts to 244 km/h in the Southern Tararuas, but I find that a little hard to believe.
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Re: 'Bomb' low crossing North Island Saturday 3 March

Unread post by jamie »

what about Patea, did that place get higher than those you just reported Nev, because they had a lot of damage. Or is it just that Patea isnt built to sustain winds like that compared to places like castlepoint and wellington?
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Re: 'Bomb' low crossing North Island Saturday 3 March

Unread post by Manukau heads obs »

Patea sticks out a bit on the coast there and they get westerly gales alot there
the trees are all bent over from the west wind
they are used to westerly gales in Patea (I drove through there just last year)
so to get the damage they got, it must have been 150kmh winds
(there is a funneling affect, i.e the wind going around past Mt Taranaki)
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Re: 'Bomb' low crossing North Island Saturday 3 March

Unread post by Nev »

Looking at the 6am hand-drawn mean sea level analysis map in that excellent MetService Blog, you can see how winds and gusts at Patea may have well exceeded those I quoted above (which btw were all from very exposed and relatively uninhabited sites).

Also, according to NIWA's data, 3 seperate WS's at Wanganui recorded around 972 hPa not long after 6am.
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Re: 'Bomb' low crossing North Island Saturday 3 March

Unread post by Tornado Tim »

Hand-drawn Analysis Map drawing is real true skill, I'd like to thank the Metservice for that fantastic blog post and well warning the public before the low hit.
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Re: 'Bomb' low crossing North Island Saturday 3 March

Unread post by Manukau heads obs »

It will go down in the record books for Taranaki that storm alright
Here is a coast line that is used to big westerly (or SE) gales
but this one was something else
imagine if it had cross the waikato like the models originaly had!
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Re: 'Bomb' low crossing North Island Saturday 3 March

Unread post by jamie »

Manukau heads obs wrote:imagine if it had cross the waikato like the models originaly had!
would hate to think of the damage!
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Re: 'Bomb' low crossing North Island Saturday 3 March

Unread post by Manukau heads obs »

I'd like to thank the Metservice for that fantastic blog post and well warning the public before the low hit.
and Weather Watch did a great job too
there was some people who thought yeah right before hand (mainly because they could not see the low on the satellite image (I did put a x marks the spot at one stage to make it easier)
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