Sth Pac & Aus Tropical Cyclone Season 2021-22

[Nev]

As CT is not updating our current TC Season, I thought it might pay to start this thread.

NIWA are expecting 9-12 named TC's for the Southwest Pacific this season (average is about 10.4), with at least 3 becoming severe. La Nina usually means elevated activity in the west (P.N.G., Solomon Islands, Vanuatu and New Caledonia), and reduced activity east of the Date Line.

https://niwa.co.nz/climate/southwest-pa ... tober-2021

[Nev]

JTWC issued a TC Formation Alert for the developing low near the Solomon Islands yesterday morning. The BoM also began issuing track-maps late yesterday and expect this low to be named later tonight, before reaching Cat 3 as it approaches New Caledonia on Monday night.

[Awhituobs]

it looks like its going to provide lots of energy for the tasman low
atmospheric river
lots of rain coming

[Nev]

Interesting terminology from the JTWC earlier this morning…

93P is currently quasi-stationary and hunkering over an area of very warm sea surface temperatures (30-31 C).

Development of this system appears to have slowed somewhat and the BoM now don't expect it reach TC intensity until later tomorrow, before approaching New Caledonia as a high end Cat 2 during Monday.

[Nev]

TC Ruby was named by the BoM this afternoon around 4pm NZDT.

[Awhituobs]

you can see the barocline leaf tail now, i.e the upper level winds/jet stream, that help steer it
that is west of the North Island
it might pass over the North Island instead of to the east
especially the longer it keeps moving SSE like it currently is and not SE

[Nev]

TC Ruby upgraded to Cat 2 by the BoM this morning and expected to intensify to Cat 3 later today and into tomorrow as it bears down on New Caledonia...

[Awhituobs]

The euro model has it passing closing than it had before, latest update, so my thinking seems legit

[Nev]

A slightly more ragged looking Ruby has been pummelling northern New Caledonia this morning.
Central pressure was down to 975 hPa overnight, but up slightly to 978 hPa this morning, with max winds around 110 km/h.

[Awhituobs]

the mountain spine of New Caledonia will not do it any favours

[Nev]

Local radar showed the eye tracking down the east coast of New Caledonia's main island of Grande Terre this afternoon. Touho Aero recorded a min MSLP of 984 hPa as the eye passed over earlier today.

[Nev]

TC Ruby was downgraded to Cat 1 by Fiji Met this morning and is expected to become extratropical in the next 6-12 hrs.
JTWC has also issued its final warning this morning. So it's 'Goodbye Ruby Tuesday' from New Caledonia...

[Nev]

Update: Ex-TC Ruby (currently about 600 km NE of Cape Reinga) survived a little longer than expected and was declared extratropical by MetService at around 7am this morning.

It was last reported as an intact TC (albeit with sheared convection and a well exposed LLCC) at around 1am this morning when it was about 760km NNE of Cape Reinga.

[NZ Thunderstorm Soc]

Although not really associated with this topic, but it is closely related, for the record, I thought that I would mention Typhoon Rai that struck the Philippines recently and caused damage in that country.

[Chris W]

Looking like a TC forming in the Coral Sea in a couple of days' time, then possibly quickly tracking along the Queensland/NSW coast and towards NZ in a week or so. That's from the UKMO, at present GFS has something much less intense passing by to the north a couple of days later, EC a little more towards GFS.

[Blowy]

Looking like a SI hit job ~5th Jan?

[Chris W]

UKMO has the ridge strengthening and forcing the TC northwards on the 4th still along the Queensland coast at that stage, haven't checked GFS.

[Blowy]

GFS = SI hit job... DYOR

[Blowy]

SI..

[NZ Thunderstorm Soc]

Straight over Geraldine

[Nev]

The BoM have maintained only a low chance of this current hybrid system off the Queensland coast forming into a TC. JTWC did issue a TC Formaton Alert yesterday afternoon, but has since retracted that.

As to what becomes of this system is anybody's guess. GFS has been a bit of an outlier compared to other main models (some even having it head back north). Most likely it will just disappear into the Tasman graveyard...

[Nev]

Spoke too soon...
TC Seth was named by the BoM this arvo. Max winds 45 knots (85 km/h), with a central pressure of 992 hPa.

[Nev]

Seth now upgraded to Cat 2. Max winds 50 knots (95 km/h), gusting to 70 knots (130 km/h), with central Pressure at 991 hPa.

[Nev]

BoM has maintained Seth's 50 knot winds overnight, with central pressure now down to 983 hPa. However, dry air and shear have removed deep convection near Seth's centre in the past 6 hours.

[Chris W]

BOM and UKMO taking Seth back across the Queensland coast and absorbing the low into a developing inland trough. GFS sends a very tame low south of most of NZ.