Technical 20/21 Australian TC and Monsoon season

Flowin

One of Us
Ski Pass
Jul 5, 2019
1,860
11,758
363
Pinjarra Hills, QLD
New thread for a new season. This season’s TC outlook issued 12 October.

C6275828-4CA8-45A7-B1B9-A30B10A82CEF.jpeg
 

Greysrigging

One of Us
Ski Pass
Jul 11, 2019
1,304
4,412
363
Darwin
Increased monsoonal activity generally indicates an increase of the chances of a Tropical Cyclone forming,
The possibility of a pre Xmas Cyclone somewhere in Australian waters is real if as, the predictions seem to say, the Monsoon is a bit earlier this season.
 

youcantbecirrus

Hard Yards
Jan 9, 2020
6
16
53
GFS has a system on its 12Zrun, but dry air is seen to wrap and inhibits further development after tau252. Very far ahead though so lets see if it gets it very wrong or very right.

gfs.png


Edit: Would love to know where all the weatherzone members fled off to after it shut down. Loved the TC forums there. I recognise Flowin
 

MegaMatch

One of Us
Ski Pass
Jul 3, 2019
2,415
11,454
363
where
BoM 4-day (12z EC) shows the monsoon trough making landfall over WA in a few days time. Definitely the monsoon trough too as it is marked dash dot dash dot rather than dash dash dash dash. The snake:

gfs_mslp_uv850_io_11.png
 

Michael Hauber

One of Us
Jul 4, 2019
560
3,104
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What concerns me though is that the tropical activity is focused in NW Australia and out wide in the coral sea, but nothing significant over NE Australia. A quick look at least 7 days cloudiness:

map_7.ps.png.small (1).png


Finally we are seeing something more like expected in La Nina (-veIOD) with clouds gathered to the north of Australia and nothing much in West Indian or central to East Pacific. This is only 7 days, and MJO is currently in a favourable location. But La Nina means MJO is likely to stay favourable for much greater portion of the cycle. However there is a weird clear spot over NE Australia almost joined with the typical clear area along equatorial Pac.

Going back to winter we see cloudiness north of Australia is not at all La Nina like with clouds stronger in west Indian and NE Pacific. Strong suppression of cloudiness is visible along equatorial Pacific. While early in the year and ahead of a La Nina being declared other La Nina years typically have enhanced cloudiness near Australia from winter (but small dataset only going back to 2001)

202006.global_olr.ps.png.small.png


For Spring the situation has improved a little, but the Indian ocean seems balanced with equal anomalies between West and East. Also cloudiness anomalies near Australia seem lopsided N-S, being much stronger in Northern Hemisphere.

202009.global_olr.ps.png.small.png
 
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CCKW

Hard Yards
Dec 14, 2020
44
131
33
Todays 00z shifted the low west of the previous run. Still showing the brown ocean affect ie strengthening the low whilst overland. This low as-per the model with overland strengthening suggests there will be a strong monsoon flow into the low. Moisture flux's.

71viSP.gif



71vcd1.gif


This type of system in oz unless it forms while over water don't get classified. Noaa now days in the ATL classify these as td's when they form overland.
 
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Claude Cat

On my bike
Moderator
Ski Pass
Jul 6, 2001
129,530
84,446
3,525
Canterbury, Vic
Cyclone or just a very strong inland low?
Looks to be affecting central Australia and the SE through Monday and Tuesday.
 

Rabid K9

A Local
Ski Pass
Jul 15, 2008
5,906
6,536
563
Thinking it will be ts wind wise. Due to friction would not think much over 100kmph ,but wont to be classified as such overland.


18Z
ecmwf-deterministic-waus-mslp_anom-8584400.png

Delivering in rain in buckets already.

Geographically widespread 100mm+ total overnight, Lombadina community on the NW of the Dampier Peninsula already passed 140mm in the few hours from 0900-1200 today.

Looking at the semi stationery rain band & infeed over next 48 hours, think a few places will see over 500mm out of the system, even if the recording stations are few & far between. Cygnet Bay, just to the east of Lombadina already collected over 400mm out of the previous system earlier in month.
 
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Claude Cat

On my bike
Moderator
Ski Pass
Jul 6, 2001
129,530
84,446
3,525
Canterbury, Vic
Delivering in rain in buckets already.

Geographically widespread 100mm+ total overnight, Lombadina community on the NW of the Dampier Peninsula already passed 140mm in the few hours from 0900-1200 today.

Looking at the semi stationery rain band & infeed over next 48 hours, think a few places will see over 500mm out of the system, even if the recording stations are few & far between. Cygnet Bay, just to the east of Lombadina already collected over 400mm out of the previous system earlier in month.

Flood Summary

Issued at 11:49 AM on Sunday the 20th of December 2020

The following Watches/Warnings are current:

Flood Warning for the North Kimberley District
Flood Warning for the West Kimberley District
Flood Watch for the East Kimberley Rivers including the Ord River, Sandy Desert,
Sturt Creek District and Tanami Desert
Initial Flood Warning for the Fitzroy River
 

Dylan Kearney

Addicted
May 27, 2019
71
368
133
This tropical low looks good! Appears to be an overland eye on the latest sat pass.
 

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Hermon

One of Us
Aug 24, 2008
2,290
1,555
363
The usually very dry Giles in WA has had a spectacular December. 128mm MTD!
 

CCKW

Hard Yards
Dec 14, 2020
44
131
33
When is Queensland going to get a monsoon?

There is literally hundreds of 850mb meridional flow and zonal wind forecast plots covering north and south of the EQ on the net. With all your own local experience and the collective QLD forum knowledge of incoming mt setups which would be a few hundred years if all added up i guess tell us.
 
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StormyLee

One of Us
Jul 6, 2019
340
873
263
Pilbara WA
looks frontal now.
frontal.png



What was surprising is the 200mb showing it reached all the way up there weakish up there but surprising none the less.

2oomb.png

200mb

It gave it a red hot crack didn't it. Shame things didn't line up better for the low to move offshore and dip it's toes in the water, we could've had a beauty on our hands. Should continue to meander around Kununnarra / Darwin / Broome over the next couple of days, dragging the monsoonal trough down until Thursday in the central WA/NT border area giving them a few more heavy showers at least.
 

CCKW

Hard Yards
Dec 14, 2020
44
131
33
Yeah 18z was a building ridge under it nudging the vorticity back N. Would be mostly mid-level i guess @ that time but if it could get over water in good conditions re shear wise no reason why it could not regenerate.

ecmwf-deterministic-aus-mslp_norm_anom-8714000.png
 

Flowin

One of Us
Ski Pass
Jul 5, 2019
1,860
11,758
363
Pinjarra Hills, QLD
Here is an interesting comparison between the current operational GFS (pic1) and the pilot next version of GFSV16 (pic2).
With the same initialisation time and chart for the same simulation time-step.
Makes one wonder if the new version V16 is going to produce even more wild scenarios when it goes live.
And yes I know it is only one forecast, so we will need to see how V16 performs over multiple forecasts.
sfcwind_mslp_cont.au GFS.png
sfcwind_mslp.au GFSV16.png
 

Rabid K9

A Local
Ski Pass
Jul 15, 2008
5,906
6,536
563
ecmwf_z500_mslp_aus_11.png


EC has something out in the distance off the NW coast. Not supported by GFS yet.

Jokers to the left, jokers to the right, stuck in the middle again....

All I see is that bastard bunching of the isobars on the SW corner again.

Wind & more wind. Barely dropped below 25 knots for weeks in some areas.
 
Sep 27, 2019
40
303
133
There is definitely a swing towards the possibility of TC development in the coming weeks. The latest Queensland State forecast indicates the following from the 3 January: " North to northwesterly flow will increase over the tropical northwest as a monsoon trough is re-established over the NT". TC development increases with the onset of a monsoon trough. The latest Access-G charts indicate that this monsoon trough might be dragged towards SEQ towards the end of its run https://www.weatherzone.com.au/models/?lt=wzcountry&lc=aus&mt=accessg&mc=mslp&mso=0&mh=192&focus=mh. It's early days, but there is a shift.
 

Rainbomb

One of Us
Dec 3, 2019
110
758
263
Caboolture
TROPICAL CYCLONE ADVICE NUMBER 1
Issued at 11:19 am EST on Saturday 2 January 2021

Headline:
A tropical low over the western Gulf of Carpentaria is expected to move east-southeast and intensify during Sunday.

Areas Affected:
Warning Zone
None.

Watch Zone
NT/Qld Border to Pormpuraaw.

Cancelled Zone
None.

Details of Tropical Low at 10:00 am AEST [9:30 am ACST]:
Intensity: Tropical Low, sustained winds near the centre of 35 kilometres per hour with wind gusts to 75 kilometres per hour.

Location: within 55 kilometres of 14.7 degrees South 137.0 degrees East, estimated to be 230 kilometres north northwest of NT/Qld Border and 315 kilometres northwest of Mornington Island.

Movement: southeast at 7 kilometres per hour.



The tropical low may develop into a tropical cyclone during Sunday night over the far southern Gulf of Carpentaria.

The tropical low or cyclone is expected to move southeastwards and cross the southeastern Gulf coast during Monday.


Hazards:
GALES extending to 100 kilometres from the centre of the tropical low are expected to develop about coastal and island communities between NT/Qld Border and Kowanyama during Sunday night.



ABNORMALLY HIGH TIDES and large waves are expected about the southeastern Gulf and western Cape York Peninsula as the system approaches the coast.



HEAVY RAINFALL that may lead to flash flooding about the southeastern Gulf of Carpentaria, southern Cape York Peninsula and adjacent inland areas.

cyclonewarning1.png
 

Rabid K9

A Local
Ski Pass
Jul 15, 2008
5,906
6,536
563
It was early in the evening but pretty well nothing since. All moved south to the Ingham/Townsville area.

Round 2 tonight?

Some impressive rainfall totals since late PM.

South of you, but the Herbert River gauges are very lively. Getting towards major flood levels downstream.

Herbert R.png
 
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