TC Gabrielle

 

 

We're well into the TC cyclone season for 2022-23, and with that comes the formation of TC Gabrielle. Officially named by the BoM today, the TC has formed over the Coral Sea to the west of Northern Queensland. 

 

Gabrielle isn't that pretty right now, but it is already looking to be a large TC. ZoomEarth image as at 2000 today:

 

 

We're watching this one closely. The main models all agree that the path of the cyclone will across Northland, Auckland, and Bay of Plenty, late Sunday and into Monday. All these areas have seen significant rainfall in the last 2 weeks, and are still in the process of mopping up.

 

Australia's BoM have provided a good description of what is going to happen over the next few days:

 

The forecast track is based on a weak mid-level ridge to the east of the
Gabrielle and is forecast to steer Gabrielle to the south through Wednesday. An
upper trough is amplifying over the Australian continent and is forecast to
become the dominant steering influence and takes Gabrielle southeast from
Thursday. An ensemble of numerical weather prediction models give good
confidence in the forecast track, with Gabrielle expected to remain well to the
east of the Queensland coast. The long term track takes Gabrielle close to
Norfolk Island over the weekend. This track produces a dynamic fetch of gale
force northerly winds expected to produce large northerly swells for southern
Queensland. 

The environment is favourable for further development tonight and into Thursday
as low-level and mid-level moisture remains high. CIMSS upper level winds
currently analyse Gabrielle in an area of strong upper divergence with outflow
channels to the south and north, and 15 to 20 knots of deep layer shear. 

Through to late Friday, the moisture availability will remain high, as
Gabrielle will along track SSTs of 28 to 30 degrees Celsius. Upper outflow to
the south will be enhanced as the upper trough approaches to the south.
Gabrielle is forecast to intensify to Category 2 overnight and to continue to
intensify into a severe tropical cyclone on Thursday. SHIPS RI guidance
suggests a moderate chance of rapid intensification, with the environment
improving. The upper trough will provide increasing vertical wind shear from
Friday, with Gabrielle forecast to gradually transition into a vigorous
sub-tropical cyclone over the weekend as it moves near Norfolk Island.
Gabrielle may weaken a little as this occurs, but is likely to remain at
category 2 intensity with storm force winds and a very large area of gale force
winds even as it loses its tropical characteristics. Gabrielle is likely to
remain a strong low pressure system into next week well outside of the
Australian region. 

Copyright Commonwealth of Australia

Windy.com give a better view of what is likely to happen over the next week. This is the most recent ECMWF model, but that said, all the main models show a similar track path, meaning the confidence in the track is high.

 

 

Further updates tomorrow night!

 

Not too much further to report tonight. TC Gabrielle is currently a CAT2 TC, and expected to increase toa CAT3 intensity tomorrow (2am Friday to 2am Saturday NZDT). As it continues to move southwest over slightly cooler waters it is then expected to decrease in intensity. However the associated wind and rain is now set up and it's this that is expected to hit the northern part of New Zealand on Sunday and into Monday.

 

The BoM's latest technical advisory provides the following information:

 

Gales have previously been in the eastern sector, 22:40 UTC ASCAT pass
confirming the significant extent in northeast quadrant and extending further
into the southwestern quadrant. Model guidance is consistent with peak winds
being in the northeast quadrant.   

The forecast track is based on a weak mid-level ridge to the east of the
cyclone steering Gabrielle currently to the south before an upper trough over
the Australian continent soon becomes the dominant steering influence, to steer
Gabrielle to the southeast. Model guidance is highly consistent providing
confidence in the forecast track, with Gabrielle expected to remain well to the
east of the Queensland coast. The long term track takes Gabrielle close to
Norfolk Island over the weekend. This track produces a dynamic fetch of gale
force northerly winds which is expected to produce large northerly swells for
southern Queensland.   

The environment is conducive for further development over the next 24 to 30
hours. CIMSS upper level winds currently analyse Gabrielle in an area of low
wind shear with strong upper level outflow especially to the south. Gabrielle
will remain over warm SSTs until Friday (10 Feb) when they reduce below 28C,
then falling below 26C on Saturday (11 Feb). Gabrielle is forecast to gradually
intensify, peaking at category 3 intensity on Friday.  

During Friday the upper trough will provide increasing vertical wind shear and
Gabrielle is forecast to gradually transition into a vigorous sub-tropical
cyclone over the weekend as it moves near Norfolk Island. Gabrielle may weaken
a little as this occurs, but is likely to remain at category 2 intensity with
storm force winds and a very large area of gale force winds even as it loses
its tropical characteristics. Gabrielle is likely to remain a strong low
pressure system into next week well outside of the Australian region.  

Copyright Commonwealth of Australia

Tonight's image from Windy.com shows the ECMWF predicted track up to 7am, Tuesday14th February.

 

 

This is one of the main models however this still some variation in some of the other models. It's probably safe to say at this point that there will be a direct impact on Northland and Auckland, but exactly what that will look like  is still unknown at this point. With this in mind, Metservice have today issued watches for these areas already for next week, and these are expected to be upgraded to warnings at some point. Additionally, the state of emergency in place in Auckland since the last weather event, has been extended into a third week, in main because of the cleanup work that still continues, and the predicted inpact from what will then be Cyclone Gabrielle.  More information tomorrow.

 

 

Update at 7pm tonight from Australia's BoM:

Tropical Cyclone Gabrielle is likely maintaining intensity as it gradually
evolves into a subtropical cyclone and continues moving rapidly southeast
towards Norfolk Island. 

Position based primarily on animated Vis imagery from Himarawi-9. Dvorak
analysis is becoming less meaningful as shear over the system increases and
deep convection reduces and becomes more removed from the centre. system could
not be assigned a DT from Dvorak analysis with no deep convection within 80 nm
of the centre. MET with a W+ trend is 3.0. FT set at 3.0 and CI remains at 3.5
with weakening constraints.  

The system has likely maintained intensity through much of today as it
gradually evolves into a subtropical cyclone. An AMSR2 pass at 11/0234UTC
depicted an expanding wind field with a large area of storm force winds in most
quadrants, but with a wedge of weaker winds on the northern flank of a frontal
boundary extending ESE from the centre, which happens to be over Norfolk Island
at present -- maximum wind gust from Norfolk Island Airport has been 102 km/h
(55 knots). This pass also a small patch of hurricane strength winds to the
southwest of the system, but coincident with the remaining deeper convection.
Objective aids have generally fallen below 40 knots, but are becoming less
applicable as the system becomes more subtropical in nature. Intensity
maintained at 60 knots based on AMSR2 pass.  

Gabrielle is undergoing a gradual transition through hybrid/subtropical phases,
with some clear asymmetries present. This is supported by CIMSS Automated Phase
Classification analysing the system as "borderline trop/subtrop". The synoptic
environment is unfavourable to sustain a true tropical cyclone as wind shear
persists over 40kn and the system is now over SSTs below 26C, and moving into
even cooler SST. Nevertheless, the strong low level circulation, supported by
strong upper level outflow and baroclinic processes provided by the upper
trough to the west is likely to sustain a strong system for the next 6 to 9
hours, before it becomes more vertically stacked as the upper trough moves over
the low level circulation and it begins a weakening trend. Most model guidance
suggests there is a reasonable chance this weakening will occur rapidly enough
to prevent storm force winds moving over Norfolk Island. 

Gabrielle is being steered by upper level northwesterlies, ahead of a trough
located over the Tasman Sea. There is high confidence in the forecast track
with strong agreement between model guidance (deterministic or ensemble)
resulting in a very narrow cone of confidence associated with the track of
Gabrielle. 

Gabrielle will pass very close to or over Norfolk Island in the next few hours.
Gabrielle will continue to transition to a sub-tropical low but remain a robust
circulation into next week as it moves closer to New Zealand.  

Copyright Commonwealth of Australia

Northern parts of New Zealand, including Auckland will now be experiencing some rainfall from the outer bands of Gabrielle. This is expected to increase over the next 24 hours. New Zealand's Meteorological Service have issued Red and Orange warnings and watches for much of the North Island. For the latest current watches and warnings you should always refer to  the Metservice website 

 

Councils and Emergency Management services have been advising people to prepare for the upcoming weather system. Essentially people are being told to prepare to look after themselves for up to 3 days. Corommandel and Thames have already been told to prepare for evauation. Air New Zealand have already cancelled flights and is investigating moving planes out of Auckland to avoid damage.

Tonights track image is below.

 

 

Live media updates are available below:

Stuff.co.nz 

 

 

TC Gabrielle is now an exTC> As it moved across Nortfolk Island it formally transitioned to Cyclone Gabrielle:

 

As you can see, associated cloudbands cover all of the North Island and the  top part of the South Island. In Wellington today we have seen alot of cloud, but no rain as such. The main rain bands are still tucked in towards the front centre of the cyclone as the following shows:

 

 

 

 The above diagram also shows the current predicted path for ECMWF model. Both the UK Metservice and the Austalian Bom have models describing a slightly more easterly path, and the inconsistency between the three models means that where the actual impacts of Cyclone Gabrielle will be is still unclear.

 

MetService have issued red heavy wind and rain warnings for Northland and Auckland with 200mm of rain and wind speeds of up to 130km/h expected.

 

All Rail services north of Marton cancelled tomorrow. this includes all commuter trains in the Auckland Region.

Auckland Harbour Bridge closed at 3:30pm this afternoon. Aucklanders advised to stay at home tomorrow

Northland have declartred a State of Emergency

MetServce forecasters say this a significant weather event, the type of which hasn't been seen in many years.

Power out to 15 000 Auckland residents. More outages are expected.

Niwa have release new sea swell maps, indicating waves nearing 11m in the Bay of Islands today. https://www.newshub.co.nz/home/new-zealand/2023/02/cyclone-gabrielle-new-maps-show-waves-over-12m-tall-highest-risk-of-coastal-flooding.html

 

Tonight and tomorrow will be key periods for Northland and Auckland, while the next few days will be critical for Coromandel, East Coast and further south.

 

In the mean time please keep up to date with the latest forecasts and warnings at Metservice.com, and heed the advice below.

 

An Official Government update about Cyclone Gabrielle has been issued Sunday morning by NEMA, the government's lead agency for emergency management.

Shortly before 11am Sunday, NEMA circulated the following message:

Official Government update – Cyclone Gabrielle Cyclone Gabrielle will impact much of the North Island with severe gales, heavy rain and very large waves forecast from today through to Tuesday. This is expected to be an unprecedented and dangerous weather event.  MetService has issued severe weather warnings for many parts of the North Island. Keep up to date with MetService weather warnings and advice from your local Civil Defence Emergency Management Group.   Adhere to all advice and instructions from authorities. Cyclone Gabrielle will also exacerbate the impacts for those communities recovering from recent floods Avoid travelling during severe weather, and check Waka Kotahi for road closures.  Do what you can to prepare your household for the coming days. Information about preparing for storms can be found at getready.govt.nz.  Call 111 if you feel in any danger. Stay safe. Don't take any chances.

 

Cyclone Gabrielle continues to move South East, and is currently centred around the Hauraki Gulf

 

The image below shows an infra red satellite view, with a wind speed layer on top. In terms of coluring, think of grey colours as sea level temperature. The brighter the white the higher the cloud. Some of the cloud mass has been artificially coloured, in this case in a range from blue to green, to light green to red. In that order, the higher / colder the cloud and the more chance of heavier rainfall. The video shows a 2 hour period.

 

 

 

The first thing to notice is the size of the cyclone. There is significant rainfall now across northern and central North Island, and this moves slowly down the island. This is expected to push down to Wellington, Nelson, Marlborough and Kaikoura tomorrow and the next day.

 

The next video  shows rain impacts, from 12am this morning out to Friday, based on ECMWF model. You can see in this video that heavy rain is going to impact a number of areas in the North Island, which is the reason for the number of wind and rain warnings issued by the met service.

 

 

Finally, forecasted wind impacts are as follows:

 

 

You can see that strong winds (in the red) will impact the West Coast of the North Island for a period, as the cyclone rotates down and to the East. Wellington will see strong winds all the way through to Friday

 

Cyclone Gabrielle today has caused significant issues in Northland, Auckland and Coromandel.  However from the analysis above you can easily see things aren't over yet. Gabrielle is a big system!

 

Not too much to add meteorological wise tonight. The predicted cyclones path  and impacts incl rain and wind are similar to last night. The centre of the cyclone has a pressure of around 975mb, which is extremely low. The centre lies to the east of Ruatoria, and will continue to move South East over the next few days.

 

There have been significant impacts as the system has moved down the North Island. Auckland has had an opportunity to view the damage, while Napier, Hastings and the East Coast, have been hit hard.  Power and Internet has been cut to much of this area, as has mobile coverage, and communication with people around Wairoa remains difficult, via satellite phone. Wairoa is cut off from both the North and the South and it is know that the river has burst it's banks.

 

A state of national emergency was declared today, meaning that  management of resources and support is provided at government level, as opposed to regional level, and covers areas closest to the cyclones path. This is only the third time this has been called in NZ's history. Many have not seen such similar impacts since Cyclone Bola, and Cyclone Gabrielle is being termed a "once in a generation" storm.

 

225,000 people are without power. In some cases it will be 2 to 3 weeks before power can be restored. It's estimated 2500 people have been displaced.

 

For further details on impacts today we have provided a number of media clippings for reference. Further updates tomorrow.

 

Cyclone Gabrielle continues to move away from the country. There remains a bit of a flick in the tail, in the Lower North Island tonight and tomorrow, with Orange rain warnings in place for the eastern hills of Wellington across to Wairarapa. The same area to the west is under a rainfall watch for a similar period of time. Christchurch, Canterbury and Kaikoura also seem to be getting some rain at the moment.

 

The cyclone has a central pressure of around 984mb, so a 10mb increase in the last 24 hours. It's still a deep low, but as you can see, it's not as deep as it was!

 

 

The video above shows the wider view of what's going on. Gabrielle has muscled it's way in before a blocking high on the right hand side. As the high pressure to the east is not moving, the only way the system has to go is round the bottom. So the blocking high is responsible for the cyclone slowing down as it moved across the upper and central North Island. This has meant that the cyclone has stayed around longer than it normally would without the blocking high, and therefore it's impacts have been more severe. 

 

There is a good descripton here of the processes at work: 

 

 

 

RNZ.co.nz - Live updates for today:  https://www.rnz.co.nz/news/national/484138/live-weather-updates-cyclone-gabrielle-lashes-north-island

RNZ.co.nz - Some excellent graphics describing the imbact of Cyclone Gabrielle: https://www.rnz.co.nz/news/national/484132/by-the-numbers-cyclone-gabrielle-s-impact

Newshub.co.nz Live updates for today: https://www.newshub.co.nz/home/new-zealand/2023/02/weather-cyclone-gabrielle-live-updates-monday-february-13.html

 

stuff.co.nz - Live updates for today: https://www.stuff.co.nz/national/weather-news/300806079/live-state-of-national-emergency-declared-as-cyclone-gabrielle-smashes-nz

stuff.co.nz - https://www.stuff.co.nz/national/300807271/cyclone-gabrielle-rse-workers-stranded-on-rooftops-for-hours-finally-rescued

stuff.co.nz - https://www.stuff.co.nz/national/weather-news/300806476/cyclone-gabrielle-dramatic-photos-of-boat-rescue-off-great-barrier-island

stuff.co.nz - https://www.stuff.co.nz/national/weather-news/300806341/in-pictures-cyclone-gabrielle-cuts-path-of-destruction

stuff.co.nz - https://www.stuff.co.nz/national/300806160/cyclone-gabrielle-what-you-need-to-know-in-your-region

rnz.co.nz - Live updates for today: https://www.rnz.co.nz/news/national/484187/live-weather-updates-cyclone-gabrielle-unleashes-fury-across-north-island

rnz.co.nz - In pictures: https://www.rnz.co.nz/news/national/484213/widespread-damage-cyclone-gabrielle-in-pictures

newshub.co.nz - Live updates for today: https://www.newshub.co.nz/home/new-zealand/2023/02/weather-cyclone-gabrielle-live-updates-tuesday-february-14.html

newshub.co.nz - In pictures: https://www.newshub.co.nz/home/new-zealand/2023/02/in-pictures-new-zealand-devastated-by-cyclone-gabrielle.html

newshub.co.nz - https://www.newshub.co.nz/home/new-zealand/2023/02/cyclone-gabrielle-many-gisborne-residents-without-power-phones-or-internet-cyclone-tears-through-region.html

 

rnz.co.nz - https://www.rnz.co.nz/news/national/484243/completely-isolated-wairoa-only-has-one-day-s-food-civil-defence-says

rnz.co.nz - https://www.rnz.co.nz/news/national/484285/cyclone-gabrielle-death-toll-rises-to-four-police-hold-grave-concerns-for-some-missing-people

newshub.co.nz - Live updates for today: https://www.newshub.co.nz/home/new-zealand/2023/02/weather-cyclone-gabrielle-live-updates-wednesday-february-15.html

newshub.co.nz - https://www.newshub.co.nz/home/new-zealand/2023/02/cyclone-gabrielle-incredible-footage-shows-extensive-slips-flooding-on-major-coromandel-highway.html

stuff.co.nz - Live updates for today: https://www.stuff.co.nz/national/weather-news/300807300/cyclone-gabrielle-live-updates-deaths-destruction-and-evacuations-as-force-of-storm-continues

 

 

 

 

 

The following information is  automatically collated from tweets mentioning the term #CycloneGabrielle