Tropical Cyclone Gabrielle

Nev · Unread post by **Nev** » Sun 05/02/2023 20:13

All eyes on the developing low near Vanuatu, which could ultimately be heading NZ's way in about a week's time.
The BoM expect it to rapidly intensify in the next few days, with a high chance of becoming a TC by Wednesday, if not before.

NZ Thunderstorm Soc · Sun 05/02/2023 21:02

Oh! No! Not Auckland again?

David · Unread post by **David** » Sun 05/02/2023 21:14

Certainly one to watch. Current GFS has it crossing Auckland at 974 hPa

David · Unread post by **David** » Mon 06/02/2023 12:24

Saving this here for posterity

Of course, still early days and it may miss us entirely

cbm · Unread post by **cbm** » Mon 06/02/2023 12:45

David wrote:Saving this here for posterity
Of course, still early days and it may miss us entirely

GFS seems to do this quite often in summer, the concern this time for me is how EC also has it coming close enough to do damage, and the context of what's already happened this year

Was wondering if a town of more than a few hundred had ever been completely cut off by road with damage that was months not days to repair, then remembered that has actually happened, not that long ago with the Kaikoura earthquake. Whitianga and Tairua/Pauanui combined have >10k permanent residents.

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jamie · Unread post by **jamie** » Mon 06/02/2023 13:31

Access nailed the last tropical flow over us. Access has it missing. Until it’s migrating south toward us I’m going to go with access to get a feel if we will be impacted or not.

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Blowy · Unread post by **Blowy** » Tue 07/02/2023 02:40

Could this be named Cyclone Len?
Yikes, 968 over AKL - Access coming into agreement too.

Nev · Unread post by **Nev** » Tue 07/02/2023 06:23

Blowy wrote: ↑Tue 07/02/2023 02:40 Could this be named Cyclone Len?
Yikes, 968 over AKL - Access coming into agreement too.

No, it will either be named Gabrielle or Herman.
Also that GFS track map actually says 975 mb (hPa) near Akld in 168 hrs.
However, GFS now have its centre passing a little more NE of NZ.

Nev · Unread post by **Nev** » Tue 07/02/2023 06:24

Good deep flaring convection overnight as this low intensifies, with SST's around 29-30C and low shear. BoM now expect to name it around Thursday morning.

harveyt86 · Unread post by **harveyt86** » Tue 07/02/2023 10:37

As much as I love some good weather excitement, probably best for all involved if this one shoots off to the east.

harleyb · Unread post by **harleyb** » Tue 07/02/2023 10:50

GFS the outlier at the moment

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harveyt86 · Unread post by **harveyt86** » Tue 07/02/2023 12:46

GFS back in line. A lot of models currently showing a stall and painfully slow progress over upper North Island. Lots of time for things to change but going to be hard to look away from the models over the coming days.

JP. · Unread post by **JP.** » Tue 07/02/2023 12:48

harveyt86 wrote: ↑Tue 07/02/2023 10:37 As much as I love some good weather excitement, probably best for all involved if this one shoots off to the east.

Agree with these thoughts, the last thing Auckland needs right now is more extreme weather

Nev · Unread post by **Nev** » Tue 07/02/2023 20:26

JTWC have issued a TC Formation Alert this evening and, along with the BoM, has a high chance of this low becoming a TC from tomorrow. Still a little disorganised, but some good convective spiralling in the west and north quadrants. Max winds around 30 knots and down to 995 hPa.

David · Unread post by **David** » Tue 07/02/2023 20:36

GFS ensembles. The mean takes it just offshore to the east at 967 hPa

cbm · Unread post by **cbm** » Tue 07/02/2023 22:22

David wrote:GFS ensembles. The mean takes it just offshore to the east at 967 hPa

Which is the worst spot for rain, which seems to be in its SW quadrant at that time.

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Nev · Unread post by **Nev** » Wed 08/02/2023 08:25

The BoM expect to name this tropical low later today and will likely intensify to Cat 3 by later tomorrow and remain at Cat 3 as it enters NZ's area of responsibility (AOR) on Saturday. Quite remarkable!

cbm · Unread post by **cbm** » Wed 08/02/2023 10:10

Not sure I've ever seen the models so tightly aligned and predicting an event of this magnitude, this far out. Is there any hope that they all rely on the same source data and a tiny inaccuracy in a measurement by butterfly effect is leading to wrong prediction? We are still 6 days out.

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cbm · Unread post by **cbm** » Wed 08/02/2023 10:14

cbm wrote:Not sure I've ever seen the models so tightly aligned and predicting an event of this magnitude, this far out. Is there any hope that they all rely on the same source data and a tiny inaccuracy in a measurement by butterfly effect is leading to wrong prediction? We are still 6 days out.

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Problem with that theory I guess is that is what the ensemble of runs takes into account and the outcomes are fairly tight.

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harveyt86 · Unread post by **harveyt86** » Wed 08/02/2023 10:18

cbm wrote: ↑Wed 08/02/2023 10:10 Not sure I've ever seen the models so tightly aligned and predicting an event of this magnitude, this far out. Is there any hope that they all rely on the same source data and a tiny inaccuracy in a measurement by butterfly effect is leading to wrong prediction? We are still 6 days out.

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Yep it is quite concerning. You'd have to think, even with the tight alignment currently, that the orientation of NZ and the reliance on so many factors coming together to steer it directly to us (plus the current lead time), that the odds are still much better for a miss or less damaging swipe than a direct hit. Hopefully..

TonyT · Unread post by **TonyT** » Wed 08/02/2023 10:19

Prepare for the worst, hope for the best... At least people can't say they weren't warned.

David · Unread post by **David** » Wed 08/02/2023 10:45

Now appearing in MS severe weather outlook.

Tropical Cyclone expected to bring severe weather to northern New Zealand from Sunday onwards

A high pressure system is expected to move onto Aotearoa/New Zealand from the Tasman Sea by Friday.

Meanwhile, a tropical low in the Coral Sea is expected to develop into a Tropical Cyclone. MetService is monitoring the evolution of this system closely. More information can be found at www.metservice.com/warnings/tropical-cyclone-activity.

Indications are that it is likely to move southeastwards and lie northwest of the country over the weekend, approaching the north of the North Island on Monday. Easterly winds are likely to pick up about northern parts of the North Island during the weekend, and there is low confidence of both warning amounts of rain and severe gales for Northland.

On Monday, there is moderate confidence of warning amounts of rain for Northland, Auckland, Coromandel Peninsula and Gisborne. There is low confidence of warning amounts of rain for Waikato, Bay of Plenty and Hawke's Bay. There is moderate confidence of severe east to southeast gales for Northland, Auckland, Coromandel Peninsula, Waikato, Bay of Plenty and Taupo.

Furthermore, large waves are likely to affect northern and eastern coastlines from Northland to Gisborne from Sunday into Monday.

David · Unread post by **David** » Wed 08/02/2023 13:00

GFS wants to take it below 960

harveyt86 · Unread post by **harveyt86** » Wed 08/02/2023 13:11

Getting a bit silly now...

All going to depend on what the high does. If it breaks down earlier than it could expose the west coast and South Island more. If it maintains its strength it will hopefully keep the centre north of the country. Still lots of changes to come I would imagine.

Nev · Unread post by **Nev** » Wed 08/02/2023 16:11

JTWC has just issued its first TC Advisory and Track-map. No doubt the BoM will name her in the next few hours...

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