Tropical Cyclone likely off WA - 12th Jan 2011

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Tropical Cyclone likely off WA - 12th Jan 2011

Postby von-Kármán » Mon Jan 10, 2011 8:54 pm

A fairly nasty low is developing off NW Australia, and could deepen into a TC on Wednesday / Thursday. Definitely one to keep an eye on as it could cross land.
Currently doesnt look like much ... but that is because it is in a reasonably high shear environment which will change by Wednesday
Image

Image

Image

There is also the possibility of a cyclone off QLD, but steering influences mean it probably wont come all that close to the Aus mainland, but it could affect NZ ...
At 9am Monday another low was located near 15S 112E and was nearly stationary.
This low is currently in an unfavourable environment but conditions for
development are likely to improve by Wednesday.

Likelihood of this system being a tropical cyclone in the Western Region:
Tuesday :Low
Wednesday :High
Thursday :High



NOTES: Development Potential is an estimate of the chance of each system being a
tropical cyclone in the Region for each day.
Very Low: less than 5% Low: 5% - 20%,
Moderate: 20% - 50% High: Over 50%

The Western Region refers to the Indian Ocean between Longitudes 90-125E and
south of Latitude 10S.
Further information on Tropical Cyclones is available at:
www.bom.gov.au/weather/cyclone/

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Re: Tropical Cyclone likely off WA - 12th Jan 2011

Postby von-Kármán » Tue Jan 11, 2011 10:21 am

Looking more likely now ...
Pretty decent convection despite the shear
Image

It will be intersting to see what the BoM's outlook says when it comes out later this morning. My gut is telling me that this could be a big one, pretty decent CDO already.

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Re: Tropical Cyclone likely off WA - 12th Jan 2011

Postby von-Kármán » Tue Jan 11, 2011 12:32 pm

And here is the track map:
Image

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Re: Tropical Cyclone likely off WA - 12th Jan 2011

Postby mackerelmauler » Tue Jan 11, 2011 8:08 pm

The people living in Carnarvon will be looking anxiously at the track of the system. With the catchment still wet it wont require much rain to set off another flood in the Gascoyne River.

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Re: Tropical Cyclone likely off WA - 12th Jan 2011

Postby Pete » Tue Jan 11, 2011 8:31 pm

WZ reckon the low will be 979 hPa by Thursday.

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Re: Tropical Cyclone likely off WA - 12th Jan 2011

Postby von-Kármán » Tue Jan 11, 2011 9:35 pm

Latest Sat pass shows a lovely open LLCC with some considerable convection (and associated CDO) in the western quadrant.
Image

Latest Vis shot shows some outflow bands too
Image

Shear to the South East and south is still very low (~5-10kts) and SSTs around 28-29C, but that big patch of dry air is sitting to the south and could hamper development if a dry wedge gets into the circulation. Expected to recurve acc to BoM, but seems to be some disagreement with the models ...

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Re: Tropical Cyclone likely off WA - 12th Jan 2011

Postby von-Kármán » Wed Jan 12, 2011 1:33 pm

Welcome to the world Vince!
IDW24000
Australian Government Bureau of Meteorology
Western Australia

TROPICAL CYCLONE INFORMATION BULLETIN
Issued at 8:59 am WST on Wednesday 12 January 2011
BY THE BUREAU OF METEOROLOGY
TROPICAL CYCLONE WARNING CENTRE PERTH

Tropical Cyclone Vince (Category 1) was located at 8 am WST near 14.9S 107.1E,
that is 1080 km northwest of Exmouth and is near stationary.
The cyclone is not expected to affect the WA coast in the next 48 hours.

The next Information Bulletin will be issued at 3 pm WST.


Image

Models show it recurving to the east, and possibly NOT making landfall, but there is significant uncertainty.
Image Still CDO separate from LLCC, but LLCC becoming less exposed, and this montage was from 3-4hrs ago now. Still good convection in the Western quadrant but not well organised.

A lovely shot of the exposed LLCC with CDO just to the west. Click for larger version
Image

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Re: Tropical Cyclone likely off WA - 12th Jan 2011

Postby Pete » Wed Jan 12, 2011 2:27 pm

The way the track map's looking, if it continues its course, it will make landfall just east of Port Hedland maybe Monday? Or it might track south and come down the coast.

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Re: Tropical Cyclone likely off WA - 12th Jan 2011

Postby chartphred » Wed Jan 12, 2011 8:27 pm

Hi all,
Really appreciate the analysis. But to the unitiated plebs like me could someone please explain the meaning of the above commentary - CDO? LLCC?
Is that something to do with the distinct double swirls? What appears to me to be almost two cyclones trying to form at once (but obviously isn't) if that makes sense?

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Re: Tropical Cyclone likely off WA - 12th Jan 2011

Postby Blue Skies » Wed Jan 12, 2011 9:48 pm

A LLCC is a Low Level Convection Centre. I'm not sure what a CDO is though. Centre for something?

Looking good for a decent storm, at any rate, not like the last 'maybe' low.
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Re: Tropical Cyclone likely off WA - 12th Jan 2011

Postby Blue Skies » Wed Jan 12, 2011 9:55 pm

Big_Pete wrote:The way the track map's looking, if it continues its course, it will make landfall just east of Port Hedland maybe Monday? Or it might track south and come down the coast.


The shear tendency is hinting at the Exmouth to Onslow area at the moment. As usual its a bit early to tell.
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Re: Tropical Cyclone likely off WA - 12th Jan 2011

Postby von-Kármán » Wed Jan 12, 2011 10:53 pm

Actually the official NOAA definition has LLCC = Low Level Cloud Centre (sometimes referred to as Low Level Circulation Centre) it is where (near Sea level) the winds rotate around, must admit I've never heard it refered to as a low level convection centre because often the centre of the convection is nowhere near the circulation centre, as in this case. The convection is well to the west of the LLCC ... anyway it is particularly important early in a cyclone's life as the upper level winds may not be a true indication of the location of the centre of the tropical depression / low. Once the cyclone is fully formed the LLCC and the eye are coincident.
and
CDO = Central Dense Overcast, it is a layer of typically cirrus cloud that forms over intense convection thunderstorms around a cyclone. In this case the CDO is the blob of white to the west of the LLCC int eh above shots. Once the CDO completely surrounds the LLCC and an eye forms, that is when you have a full blown cyclone. Occasionally the CDO can obscure the LLCC / eye and this often is an indication of an eyewall replacement cycle (ERC) or otherwise a weakening of the cyclone.

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Re: Tropical Cyclone likely off WA - 12th Jan 2011

Postby @weather_wa » Thu Jan 13, 2011 12:04 am

Cyclone Vince off Pilbara coast to intensify

http://www.weatherzone.com.au/news/cycl ... sify/15891

Tropical Cyclone Vince is expected to intensify, but is not expected to affect the Pilbara coast in the next 48 hours.

The Bureau of Meteorology says the cyclone is about 1,000 kilometres to the north-west of Exmouth.

Senior Forecaster Matt Boterhoven says it is expected to track slowly towards the coast.

"Tropical Cyclone Vince is a category one system; we expect it to slowly intensify into a category two system over the next 24 hours," he said.

- ABC

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Re: Tropical Cyclone likely off WA - 12th Jan 2011

Postby von-Kármán » Thu Jan 13, 2011 7:08 am

There is a new thread started in the TC forum : viewtopic.php?f=33&t=1204

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Re: Tropical Cyclone likely off WA - 12th Jan 2011

Postby chartphred » Thu Jan 13, 2011 12:20 pm

Thanks von-Karman for the explanation. Really appreciate that.
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Re: Tropical Cyclone likely off WA - 12th Jan 2011

Postby Blue Skies » Thu Jan 13, 2011 5:48 pm

von-Kármán wrote:Actually the official NOAA definition has LLCC = Low Level Cloud Centre (sometimes referred to as Low Level Circulation Centre) it is where (near Sea level) the winds rotate around, <snip>


Well, there you go. I've got the same problem as Chartphred - people are so fond of throwing out abbreviations that I either struggle to remember what they are or they morph in my memory into something else. Perhaps I can make the polite request that you take some time to explain a few of the more technical aspects from time to time so we can all keep up. I do my best and I know there are others here who would be as lost as Chartphred but would love to know. That's how we learn!
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Re: Tropical Cyclone likely off WA - 12th Jan 2011

Postby chartphred » Fri Jan 14, 2011 12:17 pm

Yes Good idea Blue Skies. But I was wondering if it would be possible for someone with a bit of Wx tech nouse to perhaps create a bit of a 'sticky' thread on definitions, terms, and the more technical aspects so that we can all go back there from time to time and refresh our memories? I guess there are probably heaps of other websites out there with definitions, but something simple would also be handy, rather than wading through a huge technical website.
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Re: Tropical Cyclone likely off WA - 12th Jan 2011

Postby Cmon Aussie Cmon » Fri Jan 14, 2011 12:23 pm

chartphred wrote:Yes Good idea Blue Skies. But I was wondering if it would be possible for someone with a bit of Wx tech nouse to perhaps create a bit of a 'sticky' thread on definitions, terms, and the more technical aspects so that we can all go back there from time to time and refresh our memories? I guess there are probably heaps of other websites out there with definitions, but something simple would also be handy, rather than wading through a huge technical website.

viewtopic.php?f=30&t=752
8)

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Re: Tropical Cyclone likely off WA - 12th Jan 2011

Postby von-Kármán » Fri Jan 14, 2011 11:08 pm

Wow! Sorry not quite sure what to do now, I thought I did provide a good explanation?? If you are not sure about a definition then Google is your friend, and I am not quite sure how muc more help I can give???

Sorry for being too technical perhaps I should just keep me trap shut ? :(

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Re: Tropical Cyclone likely off WA - 12th Jan 2011

Postby silvercloud » Sun Jan 16, 2011 2:01 pm

Don't do that Von. Some of us aren't as techy as you is all :wink: . But it's all good and as you said Google is the place to look, or the BOM site :D .

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