543 replies to this topic

[HurricaneJosh]

Aussie Region Cyclones
Because the party never ends for the Tropical Dudes-- and because Adam reminded me today-- it's time to start looking Down Under for tropical pleasures. Australia's tropical cyclone season starts in a couple of weeks-- on 01 November!

As I did previous years, I'm starting this thread with a quick primer on cyclones in Oz-- a reference source for those of you who want to get a basic lay of the land. (This info is reproduced from the previous years' threads because it's still useful!)

Geography
Here are the basic land areas and water bodies:

 post-19-0-16091000-1289497096.png   19.52K   4 downloads

Land
A large portion of Australia's coastline is threatened by cyclones. Since this is the S Hemisphere, it's like going through the looking glass-- meaning the tropics are to the N and therefore Australia's cyclone country is the N coast. This is actually a tremendous stretch of coastline that spans three states/territories:

* Queensland (QLD) (on the E)
* Northern Territory (NT) (in the middle)
* Western Australia (WA) (on the W)

Most of Australia's population is concentrated in the major cities in the SE-- Brisbane, Sydney, Melbourne, etc.-- and therefore Australia's cyclone country (up N) is mostly very sparsely populated. This means that intense cyclones often make landfall-- particularly in Western Australia-- without causing much damage.

Water
Like Mexico-- and unlike the USA-- Australia is threatened by cyclones from two oceans: the South Pacific to the E and the Indian to the W.

These two oceans are divided into several smaller bodies of water-- most of which are shallow, warm, and game for big cyclones:

The South Pacific (to the E) includes:

* Coral Sea-- along the E coast of Queensland
* Gulf of Carpentaria-- between Queensland and the Northern Territory
* Arafura Sea-- to the N of the Northern Territory

The Indian Ocean (to the W) includes:

* Timor Sea-- between Indonesia & Australia
* Joseph Bonaparte Gulf-- between the Northern Territory & Western Australia

Warning System
Australia's Bureau of Meteorology (BoM) handles cyclone warnings via its offices in the capital cities of each state/territory:

* BoM Queensland (QLD): Brisbane
* BoM Northern Territory (NT): Darwin
* BoM Western Australia (WA): Perth

Each BoM office has jurisdiction over its own region (including the adjacent waters), and when a cyclone passes from one region to the next, the responsibility for issuing advices (advisories) passes from one office to the next. Here's the regional breakdown (note that Eastern = Queensland):

 post-19-0-53795300-1289497118.png   13.54K   0 downloads

The different territories and jurisdictions means there's no convenient "one-stop shop" (like our National Hurricane Center) for tracking Aussie cyclones. (Grrrrr. ) However, the BoM simplified their Website information architecture a couple of years ago, so now there's at least one convenient URL from which you can access the different regional warnings: http://www.bom.gov.au/weather/cyclone/.

All of this aside, the USA's Joint Typhoon Warning Center (JTWC) also covers the Aussie region, and they're a good secondary info source, although-- as discussed in other threads-- the JTWC tends to go a bit high with intensity estimates.

Tracking
If you feel inclined, here's the BoM's handy cyclone tracking map for the waters around Western Australia and the Northern Territory: http://www.bom.gov.a...racking_map.pdf

Here's one for the entire N coast of the continent, including Queensland-- Australia's entire cyclone zone: http://www.bom.gov.a...let/plotmap.pdf

Cyclone Intensity
In public advices, the BoM indicates cyclone intensity by max gusts-- not sustained (1-min) wind like our NHC. (However, technical discussions will express a sustained wind-- but note that it's a 10-min wind, not a 1-min wind like ours. The conversion factor-- to change a 10-min wind to a 1-min wind-- is ~1.13 to 1.15, depending on who you ask.) Also, note that for public advices, the Aussies use km/hr-- not mph like we do.

Aussie Intensity Scale
The Aussies have their own cyclone intensity scale-- as follows:

Cat 1 = max gusts: <125 km/h (<68 kt) -- max sustained (10-min): 63-88 km/hr (34-47 kt)
Cat 2 = max gusts: 125-169 km/h (68-91 kt) -- max sustained (10-min): 89-117 km/hr (48-63 kt)
Cat 3 = max gusts: 170-224 km/h (92-121 kt) -- max sustained (10-min): 118-159 km/hr (64-85 kt)
Cat 4 = max gusts: 225-279 km/h (122-151 kt) -- max sustained (10-min): 160-199 km/hr (86-107 kt)
Cat 5 = max gusts: >279 km/h (>151 kt) -- max sustained (10-min): >199 km/hr (>107 kt)

Aussie Intensity Scale vs. American Intensity Scale
How does the Aussie scale (AUS) compare to our Saffir-Simpson scale (USA)? It has five levels, but otherwise it's quite different! Here's a side-by-side comparison with ours:

Cat 1 AUS = tropical storm USA
Cat 2 AUS = tropical storm thru low/midrange Cat 1 USA
Cat 3 AUS = high/midrange Cat 1 thru low-end Cat 3 USA
Cat 4 AUS = midrange Cat 3 thru low-end Cat 4 USA
Cat 5 AUS = midrange Cat 4+ USA

Anything Cat 3 AUS and above is described as a "Severe Tropical Cyclone"-- so, while it sounds dramatic, this label could be (and is) applied to what we would call a strong Cat 1 'cane in the USA.

Here's an excellent graphic from the BoM's FAQs which illustrates the relationship between the Aussie and American intensity scales:

 post-19-0-51005800-1289497132.png   8.82K   0 downloads
______

OK-- there's your handy reference source for tracking Aussie cyclones!

Madagascar Cyclones
As we've expanded the scope of this thread to also include cyclones in the SW Indian Ocean, I thought I'd share my research (presented last year) Re: cyclones hitting Madagascar:

I decided just to concentrate on cyclones hitting Madagascar since 2000, as this last decade has been a very active period for the island nation. For the period 2000-2009, Madagascar had:

* 12 hurricane landfalls
* 6 major-hurricane landfalls
* 1 Cat-5 landfall

The map below shows the landfall points of all the majors. As kush has pointed out previosuly, the NE portion of the island seems to be a magnet for intense landfalls-- so the second map zooms in on that region. Cyclone Bingiza from February of this year (not shown on this map) also hit the NE region and it may have been a major. Majors can hit the W coast (like Fanele 2009), but it happens much less often.

Not mentioned in these stats is a very near miss by another Cat 5-- Hary 2002-- which passed just offshore of that same NE region.

The large port city of Toamasina (pop. ~180K)-- on the E/C coast-- has been very lucky over the last decade, with no direct hits from any hurricane-strength cyclones. And the only 'canes to even come within 20 mi of the city in the last 30 yrs are Honorinina 1986 (Cat 1) and Geralda 1994 (Cat 3)-- so they've just been waaaaay lucky.

Note: Data are from Meteo France (La Reunion)-- the official agency for this region. All wind references are 1-min, converted from the original 10-min using a factor of 1.136. All scale references are the USA (SS) scale.

 madagascar1.png   107.11K   2 downloads

 madagascar2.png   67.41K   1 downloads

[k***]

I'm thankful that the thread title now officially sanctions my SWIO spam

[Ed Lizard]

Did the slowness of the 2011 Northern Hemipshere season let you save enough to visit Alby or one of our other Southern Hemisphere friends for some Down Under chasing action?

[HurricaneJosh]

k***, on 18 October 2011 - 01:29 PM, said:

I'm thankful that the thread title now officially sanctions my SWIO spam

Yes, I made this adjustment last year. The Madagascar/Mozambique region has interesting activity once in a blue moon-- not enough to justify its own thread (I didn't feel), but certainly enough to require a home somewhere.

[HurricaneJosh]

Ed Mahmoud, on 18 October 2011 - 01:30 PM, said:

Did the slowness of the 2011 Northern Hemipshere season let you save enough to visit Alby or one of our other Southern Hemisphere friends for some Down Under chasing action?

For me, it wasn't a slow year. Since I really recommitted to chasing in 2005-- after a hiatus because I was living in Europe full-time-- I've averaged 1.43 chases per year. I did 2 this year-- so it's been above average.

I will most certainly go to Oz for the right cyclone. But I'm also not holding my breath. Jova gave me a good fix.

[HurricaneJosh]

To start off the discussion... Adam linked me to the cyclone outlooks for NW Australia and Queensland today:

NW Australia highlights:

* A 60% chance of an above average number (40% chance of a below average number) of tropical cyclones in waters off the northwest coast (average number is 5).
* Likelihood of around 2 coastal impacts.
* Significant risk of at least one severe tropical cyclone coastal impact during the season.

Queensland highlights:

"North Queensland still bears the scars of tropical cyclone Yasi which crossed the coast approximately mid-way between Cairns and Townsville earlier this year, and while the outlook for the coming wet season is considerably more favourable than last year, our climate models are still leaning toward a slightly above average outlook for tropical cyclone activity in Queensland."

"Predicting the number of tropical cyclones for the coming season is not an exact science, but rather a likely range. If we consider the average for Queensland as three to four, then we might be looking at a figure slightly higher, of four to five, with perhaps one or two making landfall. This is the scenario we need to be ready for, and preparation is key."

"While our climate models are trending toward La Niña, there is no indication the activity will be as widespread and intense as last season," said Mr Davidson.

[k***]

HurricaneJosh, on 18 October 2011 - 01:35 PM, said:

To start off the discussion... Adam linked me to the cyclone outlook for NW Australia today: http://www.bom.gov.a...clone/seasonal/

Highlights:

* A 60% chance of an above average number (40% chance of a below average number) of tropical cyclones in waters off the northwest coast (average number is 5).
* Likelihood of around 2 coastal impacts.
* Significant risk of at least one severe tropical cyclone coastal impact during the season.

hopefully they don't choke like last year...22 NS

[am19psu]

HurricaneJosh, on 18 October 2011 - 01:35 PM, said:

To start off the discussion... Adam linked me to the cyclone outlook for NW Australia today: http://www.bom.gov.a...clone/seasonal/

Highlights:

* A 60% chance of an above average number (40% chance of a below average number) of tropical cyclones in waters off the northwest coast (average number is 5).
* Likelihood of around 2 coastal impacts.
* Significant risk of at least one severe tropical cyclone coastal impact during the season.

I sent you QLD too...

Go barbiecanes.

[HurricaneJosh]

am19psu, on 18 October 2011 - 02:53 PM, said:

I sent you QLD too...

Go barbiecanes.

Oops, ya did. I'll add it to that post. Thx.

[AlexD]

Has there ever been a cyclone in the Canberra/Melbourne region?

[EastCoastLow]

AlexD, on 18 October 2011 - 04:28 PM, said:

Has there ever been a cyclone in the Canberra/Melbourne region?

No. Way too far south. The prevailing weather systems sweep up any remnants and send them off into the Tasman sea before they get even close. Sydney has had one extratropical system travel over it , it maintained a fair bit of strength whilst travelling inland from the Gulf of Carpentaria. That's about as far south as they ever come. However large waves have often affected Sydney from TC's travelling offshore.
http://www.bom.gov.a...mages/TC119.gif
Interestingly, the east coast does get very good rainfall events from north west coast cyclone remnants that drift over and down with the prevailing weather patterns.
Melbourne, Sydney and to a lesser extent, Canberra do suffer from the effects of east coast lows a few times each winter though, they can be just as devastating as a small cyclone and have much less forecast time, plus their intensity is difficult to predict:
http://www.bom.gov.a...facts/ecl.shtml

[HurricaneJosh]

Hey, Tropical Dudes!

Remember to enter the Aussie cyclone contest, being hosted by American Wx's resident Aussie dude, Stephen (alby_14): http://www.americanw...ost__p__1041621

The prizes are totally awesome. He sent me copies last year and I loved 'em-- especially the Cyclone Tracy book!

[HurricaneJosh]

Given this thread's increased scope-- to include the SW Indian Ocean-- I added some background info Re: Madagascar cyclones to the first post of this thread.

[Christopher]

This thread of Aussies weather should be mixed of with American weather. Should have a seperate catagory for international weather and forecasting.

[HurricaneJosh]

boomer, on 24 October 2011 - 10:59 AM, said:

Josh... please do not put Madagascar into the Oz forum
It's so wrong.... it diminishes both.

It makes perfect sense for this forum to group S-Hemisphere activity together, given the level of interest in the subject matter (which is fairly limited). Thanks!

Christopher, on 24 October 2011 - 12:01 PM, said:

This thread of Aussies weather should be mixed of with American weather. Should have a seperate catagory for international weather and forecasting.

We've always put this thread-- like all other international threads-- in the main forum. If you want to propose a new structure for the forum, start a new thread about it-- I'm sure the staff would be interested to hear your views.

[wxmx]

Christopher, on 24 October 2011 - 12:01 PM, said:

This thread of Aussies weather should be mixed of with American weather. Should have a seperate catagory for international weather and forecasting.

Segregating it further would be detrimental, IMO. It gets relatively few posts per season...if it gets separated, and off the main page, I would think it would get a lot less activity than it does now.

[am19psu]

This thread will continue as a catchall for Southern Hemisphere tropical cyclone activity. The matter is closed.

[am19psu]

boomer, on 26 October 2011 - 10:11 AM, said:

You have already made up your mind... it's more convenient for you... stuff the rest of the world... Josh, you are good but you are also one of the most arrogant people I have ever met online...

There is absolutely no need for this. Further personal attacks will result in posting restrictions.

[Ed Lizard]

boomer, on 24 October 2011 - 10:57 AM, said:

For Ed,
I'm off to Fiji throughout November.
Hopefully not chasing.... but

Have fun. I do think a separate Western IO thread would get pretty lonely. I hope you get a Tomas before you leave.

BTW, now that the V-8 cars are on American TV live (so I set the DVR and watch later), I have to say Gold Coast and Bathurst were pretty good. Actually, glad I recorded Bathurst, 1000km is a long race, I fast-forwarded the middle and only stopped for off track excursions.

You coming to Austin and treating us Texas boys to a day at the SuperCar races in 2013?

[Ed Lizard]

Hopping thread if 4 people post just while I'm typing...

[am19psu]

boomer, on 26 October 2011 - 10:30 AM, said:

First,
To psu... What I have said does not come close to restriction. In regard to the thread Josh has laid down I believe he is incorrect. He is entitled to develop a thread and has done, no problem there. What he has missed ( and this is more about him owning the thread) is that the Aussie system is so far removed (we already work way into the Indian Ocean) from what is the reality of the thread it is not funny. The thread should be about the Aussie Cyclone season.

From the Weatherside rules:

Quote

No personal attacks/OT arguing
Try to stay on topic
Attack the idea, not the poster

You are borderline on all three of these rules.

You've offered no compelling reason why you think that it should be done your way versus the way we've always done it. Considering we only post about the SWIO when there is a monster out there, it's hardly going to derail this thread. If there were more posts about the SWIO, then it would be reasonable to split the topics. As it is, there are only 8-10 people who regularly post in the Aussie thread and most have some common interest in the SWIO. This is not a geography question, it is a traffic question. It's the same reason why the I-95 corridor has 5 different subfora devoted to it, while the entire western half of the US has a single subforum.

You are welcome to start you own forum if you wish to have separate threads. I am done with this discussion. If you press further, you will be post restricted.

[MacChump]

this is a crackling good argument

[Ed Lizard]

MacChump, on 26 October 2011 - 10:47 AM, said:

this is a crackling good argument

I feel badly for Boomer, but there just won''t be enough Southern Hemisphere/Western IO action to support an independent thread. I hope he doesn't push it with Adam, and find himself 5 posted as a Cat 5 TC is bearing down on Cairns.

[wxmx]

boomer, on 26 October 2011 - 10:06 AM, said:

Okay ... lets compare last season on this forum
50,000 Aussie hits
How many Madagascan?

Actually, the number of severe cyclone hits for Madagascar is comparable to Aussie hits, and I think the number of Madagascan hits from severe cyclones is slightly superior since year 2000, which is significant considering Madagascar is a fraction of the size of Australia.

[Ed Lizard]

Below average or above average, it just takes one Cat 4 or 5 hitting Cairns directly to make your season worthwhile for me. Or anything with winds over 65 knots, even if being sheared and becoming post-tropical, hitting Freemantle, because I drank Budwesier's in an American themed bar there. Waitresses in American flag bathing suits. Sweet.

[Srain]

am19psu, on 26 October 2011 - 10:36 AM, said:

From the Weatherside rules:



You are borderline on all three of these rules.

You've offered no compelling reason why you think that it should be done your way versus the way we've always done it. Considering we only post about the SWIO when there is a monster out there, it's hardly going to derail this thread. If there were more posts about the SWIO, then it would be reasonable to split the topics. As it is, there are only 8-10 people who regularly post in the Aussie thread and most have some common interest in the SWIO. This is not a geography question, it is a traffic question. It's the same reason why the I-95 corridor has 5 different subfora devoted to it, while the entire western half of the US has a single subforum.

You are welcome to start you own forum if you wish to have separate threads. I am done with this discussion. If you press further, you will be post restricted.

boomer, on 28 October 2011 - 09:05 AM, said:

Sorry mate... but I am pushing further, and I believe I have reason... if you wish to suspend me then go ahead.

I think there will be enough action Ed, we are set for a "crackling" LOL season. The lesser La Nina will arguably be more conducive. Yasi was something of a freak that formed in perfect conditions... (and scared the crap out of a lot us).
PSU. I admire both you and Josh but you really need to toughen up... the criticism is legitimate. What is not is the outright rejection of the argument that Madagascar and the Coral Sea are quite literally a world apart (southern hemisphere not withstanding). To put both in the one thread will cause enormous confusion if developments occur at the same time... and with the distances involved that is more than likely. In just the maritime continent area of responsibility last season there were times where three TC's (rare) were active at the same time.
You say only ten people post regularly on the Oz season... I would have thought you would have wished to grow it... this will not do that.

We have our reasons and you have been given those reason and a solution. It would be a good idea to follow those strong suggestions made by Adam.

[HurricaneJosh]

I wish this thread wouldn't keep going off topic. It's really getting annoying.

[Ed Lizard]

HurricaneJosh, on 28 October 2011 - 10:07 AM, said:

I wish this thread wouldn't keep going off topic. It's really getting annoying.

Sorry. No more from me.

[Ed Lizard]

boomer, on 28 October 2011 - 10:21 AM, said:

Josh,
As you can see above, I hardly think the Fiji AOR (which I am genuinely surprised has drawn no comment) is off topic (nor is my provision of the latest state/territory forecasts)
Look, I've put my argument forward re an OZ only thread, I've more than catered for staying on thread (I apologise for calling you arrogant)
As far as I can see that covers all three rules re banning.
That does not mean I will still not argue the point re the OZ Madagascar thread... sometimes you are wrong. Thread traffic is not the be and all... getting people to involve themselves is the key, that's what organically creates great threads.

The discussion of what should be in Josh's Southern IO thread probably should be in OT

[Srain]

boomer, on 28 October 2011 - 10:21 AM, said:

Josh,
As you can see above, I hardly think the Fiji AOR (which I am genuinely surprised has drawn no comment) is off topic (nor is my provision of the latest state/territory forecasts)
Look, I've put my argument forward re an OZ only thread, I've more than catered for staying on thread (I apologise for calling you arrogant)
As far as I can see that covers all three rules re banning.
That does not mean I will still not argue the point re the OZ Madagascar thread... sometimes you are wrong. Thread traffic is not the be and all... getting people to involve themselves is the key, that's what organically creates great threads.

Adam told you yesterday in the post I quoted that you are free to start a new discussion, should you choose. To answer your question directed at me, yes among other Tropical Mode Moderaters. Now, one more time, back on topic...

[HurricaneJosh]

The Aussie season starts today-- woo hoo!

That having been said, November is usually pretty dead-- however, activity ramps up quickly in December, when the season has the first of two peaks. Some of Australia's greatest cyclone events happened in December-- for example, Tracy 1974 and Joan 1975.

[EastCoastLow]

I'm liking SST's that are already in place, nice early warming for this season:

 IDY00008.gif   47.8K   0 downloads
 IDY00002.gif   44.73K   0 downloads

[Ed Lizard]

HurricaneJosh, on 1 November 2011 - 12:08 PM, said:

The Aussie season starts today-- woo hoo!

That having been said, November is usually pretty dead-- however, activity ramps up quickly in December, when the season has the first of two peaks. Some of Australia's greatest cyclone events happened in December-- for example, Tracy 1974 and Joan 1975.

If the Western Region issues outlooks all year, does the Australian TC season ever really end?

[wxmx]

Ed Mahmoud, on 4 November 2011 - 09:01 AM, said:

If the Western Region issues outlooks all year, does the Australian TC season ever really end?

Cyclones seem to avoid Aussie interests from June to October

[Srain]

boomer, on 16 November 2011 - 06:43 AM, said:

Just back from Fiji. Had some fun avoiding a nice low JTWC at one stage rated a moderate chance (still a chance it will go cold core).
Good to see how seriously the region is being taken.
Perhaps I will visit Madagascar next time.

Let's see. We have an invest in the WPAC and in the Indian Ocean. If you're unhappy with how the region is observed, perhaps you would feel more comfortable somewhere else.