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Aussie (& S-Hemisphere) Cyclone Action 2011-2012


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The Aussie season starts today-- woo hoo! :thumbsup:

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?

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  • 2 weeks later...

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.;)

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http://rammb.cira.colostate.edu/products/tc_realtime/storm.asp?storm_identifier=SH952012

It's quite clear why I am unhappy with how the region is observed.

See above

Too late now... as to your comment re me feeling more comfortable elsewhere... don't you think that is rather snide?

If you put up a forum, you take all comers, no matter how they may rock the established cosiness.

If you do not wish it to be a genuinely public forum then place restrictions on who can enter (or you can just make it so unwelcoming they will feel they have to go elsewhere).

Or then again, they may feel like staying.

You have got to be the biggest bore on the planet. No one cares. Move on from it.

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So, it's looking like the MJO will swing around near Dec 1. Monsoon trough setting up by the 3rd? First storm by the 7th?

Could be on the mark there! Below is from the Weekly Tropical Note, which is updated every Tuesday and can be found here: http://reg.bom.gov.au/climate/tropnote/tropnote.shtml

Weekly Tropical Climate Note

Issued on Tuesday 22 November 2011

La Niña conditions continue in the Pacific

La Niña conditions remain in place over the Pacific Ocean. Forecast models surveyed by the Bureau suggest the event is likely to peak towards the end of 2011, and persist into early 2012. It is considered unlikely that the current La Niña will be as strong as La Niña event of 2010-11.

Below average sea surface temperatures (SSTs) and sub-surface temperatures persist across the tropical Pacific Ocean. The latest weekly data from the NINO3.4 region shows SSTs are below average, at −0.8 °C. Cloudiness near the International Date Line continues to be below average.

The Southern Oscillation Index (SOI) has dropped slightly compared to last week, with a 30-day SOI value of +8.3 to the 19th of November. The contributing pressure anomalies are +0.9 hPa at Tahiti and −0.3 hPa at Darwin. The monthly SOI for October was +7.3. The 5-month running mean (centered on August) was +6.4.

La Niña periods are usually associated with above average rainfall across northern Australia during the wet season. Daytime temperatures are typically cooler from December onwards, and we tend to see more cyclone activity than normal between November and April.

See the Bureau's ENSO Wrap-Up which includes a compilation of ENSO computer model predictions.

The MJO heads into the Indian Ocean

Over the past couple of weeks, a fast moving Madden-Julian Oscillation (MJO) event has circumnavigated earth in just 30 days. A weak MJO is currently over Africa, heading east into the Indian Ocean. The majority of climate models surveyed by the Bureau of Meteorology suggest that if this MJO continues at the current speed, it will redevelop in the western Maritime Continent in early December.

Over the next week, decreased rainfall and tropical cyclone potential is likely in the northwest Pacific and the Maritime Continent, influenced by the current position of the MJO. However, an increase in cyclone potential is likely over the next week in the southwestern Indian Ocean.

Climatologically, the onset of the monsoon rains coincides with the Christmas holidays. Based on the current scenario, there is potential for an earlier onset of the monsoon across northern Australia.

See the Bureau's MJO Monitoring for more information, including rainfall maps.

Next update expected by 29 November 2011 | Product Code IDCKGEWOOO

For more information please contact [email protected]

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  • 2 weeks later...
IDW10800

Australian Government Bureau of Meteorology

Western Australia

Tropical Cyclone three-day outlook for the Western Region

Issued at 2:18pm WST on Monday the 5th of December 2011

Valid until midnight WST Thursday

Existing Cyclones in the Western region:

Nil.

Potential Cyclones:

At midday WST Monday, a tropical low was located near 12.2S 87.9E. The low is

expected to develop into a tropical cyclone to the west of 90E during Monday.

The system is expected to remain west of 90E on Tuesday but is likely to move

into the Western region as a cyclone during Wednesday.

Likelihood of this system being a tropical cyclone in the Western Region:

Tuesday :Low [out of area]

Wednesday :High

Thursday :High

Euro kills it long before it reaches W.A. But glass half full, the season is really starting,

msl_uv850_z500!Wind%20850%20and%20mslp!120!Australia!pop!od!oper!public_plots!2011120500!!chart.gif

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The NCEP page allows one to look at the GFS everywhere in the world. Except the Southern Hemisphere Indian Ocean, unless I am really missing something.

Here is the eastern IO...the west is covered by all sorts of australian sites.

http://www.weatheronline.co.nz/cgi-bin/expertcharts?LANG=nz&MENU=0000000000&CONT=afri&MODELL=gfs&MODELLTYP=1&BASE=-&VAR=prec&HH=3&ARCHIV=0&PANEL=0&ZOOM=0&PERIOD= and

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Willis Island Radar station (450km east of Cairns) is back up and running after being smashed by Yasi earlier this year. Staff had been evacuated the day before, but the radar dome got demolished and hence the radar.

It will soon be manned again meaning balloons will also be back.

Awesome news!

I was reorganizing my hard drive this weekend, including all my hurricane imagery. The radar shots of Yasi-- both from Willis Island and the radar-- are terrific additions to my collection.

Speaking of radar... The value of radar for post-analysis cannot be overstated. When a hurricane makes landfall without radar coverage, we're at a serious disadvantage afterward as we try to understand what happened and how strong it was. Hurricane Jova's landfall in a remote part of Mexico's Pacific coast in October is a good example of this. I believe it was a bit stronger than the operational estimate, but the radar site was down, and it's hard to really know what happened with the inner core without that. Grrrrr.

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Back on topic... The BoM outlooks for all three Aussie regions are totally negative for the next three days. We're in a lull.

But, on the bright side, the monsoon trough looks to be building south over the next week or so, which should mean the first threat will be following up closely behind

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By the way, Christmas is the 37th anniversary of Cyclone Tracy-- probably the most significant cyclone event in Australian history.

There's an ongoing debate about its intensity, which remains a rather contentious topic. A few years ago, the BoM's foremost Tracy expert and a thought leader in wind-pressure relationships, Joe Courtney, performed a close reanalysis of the cyclone's landfall at Darwin, and his verdict was 95 kt (10-min), which converts to ~110 kt (1-min)-- what we would call a high-end Cat 3 in the USA. As has been discussed here in the past, the cyclone was extremely small, with an RMW probably under 5 n mi-- a true microcane-- however, the inner core aimed perfectly and really smashed the city. The airport measured a peak gust of 117 kt (before the instrument failed) and 950 mb in the eye.

I'll do a more extensive post about Tracy around Christmas, if there's nothing else to talk about.

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So things are getting more active.

* A Tropical Low (92P) has formed in the Coral Sea, SE of Papua New Guinea. It's expected to develop-- however, it should stay way offshore and not affect Queensland.

* More interesting is the Euro's repeated insistence on a small, very intense cyclone forming near the Top End and threatening the Kimberley in about a week (94S). The Northern Territory outlook is now suggesting a high likelihood of cyclone formation by Friday.

post-19-0-54600200-1324371595.gif

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* A Tropical Low has formed in the Coral Sea, SE of Papua New Guinea. It's expected to develop-- however, it should stay way offshore and not affect Queensland.

Still boring.

* More interesting is the Euro's repeated insistence on a small, very intense cyclone forming near the Top End and threatening the Kimberley in about a week. The Northern Territory outlook is now suggesting a high likelihood of cyclone formation by Friday.

Yep. The big forecast dilemma is when/where does it move over land. The overnight Euro run was the first in the last 3 to keep it off land enough to intensify strongly.

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Still boring.

Totally. I felt obligated to mention it because it's on the map, but zzzzzz.

Yep. The big forecast dilemma is when/where does it move over land. The overnight Euro run was the first in the last 3 to keep it off land enough to intensify strongly.

Ah, OK. So that's why yesterday's runs looked so crappy? I hadn't looked that closely.

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