Deep Subtropical low to pass through NI, 10/7-13/7

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Re: Deep Subtropical low to pass through NI, 10/7-13/7

Unread post by Philip Duncan »

Hi Mark - no we're done for the night now. Rain eased about 90 minutes ago in Kaeo but another band about to come in...could be more localised heavy falls in the next 6 hours so check back early in the morning when Richard Green does his updates. I can't see anything further happening in the next hour or two.

I hope I can get a sleep in tomorrow...it's been a very long day!! ;-)
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Re: Deep Subtropical low to pass through NI, 10/7-13/7

Unread post by Tornado Tim »

Looks like the system is surging East now.
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Re: Deep Subtropical low to pass through NI, 10/7-13/7

Unread post by Manukau heads obs »

we have had 25mm of rain here, but did not get the strong winds (28 knots only (50kmh)
if the low had moved more SE instead of ESE, then the auckland area would have got stronger winds
Dale, if you were here in the last big easterly, where we get 2x the speed of today (55 knots around the district) ,from the east, you would have been impressed :)

still gusting to 76knots through colville channel

also,power going off here briefly every now and then...somewhere further east there might be a tree touching the lines
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Re: Deep Subtropical low to pass through NI, 10/7-13/7

Unread post by Catatonic »

Only had 26 mls of rain here, and it was blowing 50kmph overnight, would love to know what the gusts were though, our house is up on 2m piles and I could feel it shaking. Time to invest in a better weather station methinks.

Still blowing a gale now, is the worst passed?
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Re: Deep Subtropical low to pass through NI, 10/7-13/7

Unread post by mak »

Still windy & raining in Whangarei though it seems to have eased slightly over night. Had a look around the property and a couple of small trees are broken and everything's a complete mess. I'm contemplating going out for a little drive to have a nosy around. I doubt I'll be getting any golf in this weekend.
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Re: Deep Subtropical low to pass through NI, 10/7-13/7

Unread post by David »

Despite the warnings the wind never even got strong here.....didn't really get any heavy rain either
Surprising about the wind, because I though tight isobars meant strong wind without a doubt, guess not...
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Re: Deep Subtropical low to pass through NI, 10/7-13/7

Unread post by NZstorm »

Surprising about the wind, because I though tight isobars meant strong wind without a doubt, guess not...
Its blowing over the top off us. Just not getting down to ground level. It will be the sheltering effect of the land.
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Re: Deep Subtropical low to pass through NI, 10/7-13/7

Unread post by David »

NZstorm wrote:Its blowing over the top off us. Just not getting down to ground level. It will be the sheltering effect of the land.
Why would this be? (not trying to sound rude or anything just trying to understand the situation)
July 2007 saw the SE do a fair bit of damage in this area so it's not like we are particularly sheltered from this direction...

Wind starting to pick up a little bit here....quite a windchill too with 9.6°C outside here.
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Re: Deep Subtropical low to pass through NI, 10/7-13/7

Unread post by Dale »

Catatonic wrote:our house is up on 2m piles and I could feel it shaking.
Likewise Cat.. at one stage it felt like being in a washing machine, the house was rockin & rollin better than Elvis!
Would you know the date of that big blast Brian, off the top of your head? Ive only been back home since Xmas day 07 so prior to that... although the 08 winter did have some very big blasts in Pukekohe itself, I was in Christchurch for 2 months or so from September last year & only been at present Paerata address since February.

Either way, came out pretty much unscathed apart from the bowing walls an shaking house. The big crash I mentioned was the neighbours trampoline on the front lawn sailing through their fence *ouch* :B but its much better than I expected locally, only a small tree down on Cape Hill Rd.. a couple of signs buckled and twisted around the Valley Heights area of Pukke.. not much else.

Parrots survived ok, they were my main concern #-o
Oh yeah, for you Razor.. best effort for a long time ;)
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Re: Deep Subtropical low to pass through NI, 10/7-13/7

Unread post by NZstorm »

Why would this be?
Not sure but it would be interesting to look back at the July 2007 situation.

NZWP12Z sounding here. Check out the low level wind profile.
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Re: Deep Subtropical low to pass through NI, 10/7-13/7

Unread post by Nev »

This storm has already been responsible for one fatality. Just before 1am this morn, a 15-year-old girl was just crushed when a tree fell on a caravan in which she was sleeping about 23km NW of Whangarei.

Mean-winds in the Colville Channel were 144 km/h at 3am, while Tiritiri was on 93 km/h (down to 61 km/h at 9am). The outer-Gulf is still recording mean-winds of 117 km/h and still around 100 km/h at Tutukaka Harbour and the Colville Channel, but at Cape Reinga and Cape Karikari winds have eased right off to about 50 km/h since peaking at around 90 km/h yesterday evening. The Waitemata Harbour is also around 50 km/h.

Very gusty here atm. Rain's stopped with 32.5mm in the gauge. No Waiheke ferries have been cancelled.
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Re: Deep Subtropical low to pass through NI, 10/7-13/7

Unread post by Catatonic »

Yep the 10 July 07 was a way bigger blast, I remember the date as my husband decided it would be a good idea to drive up to the stock markets in Wellsford and pick up a load of sheep! Yeesh! We had a big landslip then, and friends lost 24 huge shelter belt trees, and the power was out for 5 days.

Had to open all the windows upstairs last night to blow all the smoke out from the wind snuffed fire place, so it's freezing now. 9.6 degrees with a wind chill of 2.9 degrees brrrr

Glad I flipped our trampoline Dale, ours was picked up in July 07 and slammed into the house piles, made an almighty crash.

The wind must be swirling around a lot, we are fairly protected from the SW yet its still blowing quite hard out there. Would be a brave soul to get on the ferry today.
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Re: Deep Subtropical low to pass through NI, 10/7-13/7

Unread post by Michael »

In Auckland we used to get some really good NE but we dont these days.The wind was nothing more than a standard SW here last night though its a bit windier today.
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Re: Deep Subtropical low to pass through NI, 10/7-13/7

Unread post by Tornado Tim »

Michael wrote:In Auckland we used to get some really good NE but we dont these days.The wind was nothing more than a standard SW here last night though its a bit windier today.
You couldn't resist eh Mike! :lol:
Rather disappointed with a Max wind Speed of only a measly 30.6 km/hr
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Re: Deep Subtropical low to pass through NI, 10/7-13/7

Unread post by Vertigo »

looks like the low is spinning itself out now. could it be the colder waters, or does this not occur in non-tropical storms?

not a lot to write home about time, so a bit disappointing for me personally.
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Re: Deep Subtropical low to pass through NI, 10/7-13/7

Unread post by Nev »

This deep low doesn't bear any similarities to a TC. You're comparing apples with oranges! Even if it were in the tropics, it would still be just a deep depression. Cold-cored Sub-tropical or Mid-latitude 'cyclones' draw their energy from horizontal differences in temperature, whereas TC's rely on vertical differences. And as in this case, the strongest winds are around the low's outer peripheries, as opposed to near the centre with a TC. The clearing centre which Tim alluded to, was hundreds of kms wide and bears no resemblance to an 'eye'.

Michael, Manurewa is obviously NOT typically representative of greater Auckland. Try standing at the end of Whangaparoa or jump on a ferry this morn. :rolleyes:
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Re: Deep Subtropical low to pass through NI, 10/7-13/7

Unread post by Vertigo »

:) i realise it wasnt a TC, but i figured water temperature would at least play a part. anyway, it looks like its probably the result of jetstream interaction. its really getting blown aside and stretched out now.
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Re: Deep Subtropical low to pass through NI, 10/7-13/7

Unread post by spwill »

We are quite well sheltered here in Ak City on an East/SE flow, weather trying to clear up here already. It has been rather cold, only up to 10C yesterday, currently 10c with a dewpoint of 6C.
Some heavy falls for Northland, 99mm at Kerikeri
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Re: Deep Subtropical low to pass through NI, 10/7-13/7

Unread post by Myself »

Vertigo wrote::) i realise it wasnt a TC, but i figured water temperature would at least play a part. anyway, it looks like its probably the result of jetstream interaction. its really getting blown aside and stretched out now.
Jetstreams don't pull apart mid lat lows like they do TCs in general. At some stage this low was near a favourable part of the sub tropical jet, and it's possible that now it is not. All it would mean is that it's moved into an area with weaker upper divergence. The difference with TCs is that there is no favourable parts of the jet stream for their development as a TC. All parts are bad for a TC, some parts are good for mid lat lows. It helps not to think of the jet stream as a single continuous body.
Sorry if the above is not too legible, it's "early in the morning" after all :D
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Re: Deep Subtropical low to pass through NI, 10/7-13/7

Unread post by Dale »

Bloody good for a hybrid tho... got too cold, sheared itself apart, maybe next time.
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Re: Deep Subtropical low to pass through NI, 10/7-13/7

Unread post by Myself »

That's a good point, it did have a warm core originally so shear would have played a roll in it falling apart.
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Re: Deep Subtropical low to pass through NI, 10/7-13/7

Unread post by Manukau heads obs »

I see Bob Mcdavitt has explained that the cold dense air over the auckland area, in behind the coromandel ranges ,was the reason for the gales not reaching ground level here in the auckland area
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Re: Deep Subtropical low to pass through NI, 10/7-13/7

Unread post by Dale »

Still think as it transitioned into a cold core.. lost a lot of punch hence the modelling playing silly buggers right at the last second.. entered the colder latitudes, went transient and did know what to do but maintained its wind vectors up until the last second then decided to do the bolt East as it intereacted with an upper jet. . Cold dense air.. yes but there is something amiss with this low. One for the books i reckon.
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Re: Deep Subtropical low to pass through NI, 10/7-13/7

Unread post by jamie »

the wind was certainly there up high. Watching the clouds move across the sky compared to the actual wind speed was incredible. The clouds were motoring across the sky yet it was rather calm.

And yes for the type of system i thought it would have been a lot warmer. Ahhh well im off to Tonga very early tomorrow for the week so ill get my warm air there 8) . Chance of t-storms there tomorrow too which im excited about. Enjoy the cold everyone :mrgreen: :p \:D/
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Re: Deep Subtropical low to pass through NI, 10/7-13/7

Unread post by NZstorm »

I see Bob Mcdavitt has explained that the cold dense air over the auckland area,
Yes, I was thinking that was part of the reason. As the day warmed slightly the winds did pick up a little.
This effect is common in the South Island in winter in westerly flows.
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