Storm Australian Severe Weather Forum
Severe Weather Discussion => General Weather - all topics not current severe weather. => Topic started by: John Allen on 23 November 2007, 05:05:42 PM
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This is a thread i'm going to start given the good news I recieved today. I plan to keep you all in the loop as my honours project progresses. My topic and focus for the next year is:
Extratropical bomb cyclones in the Southern hemisphere including the 27th March 2007.
With my supervisor being:
Dr Alexandre Pezza, well known for this piece:
http://www.earthsci.unimelb.edu.au/~apezza/climate.dir/papers/2006/Pezza_Simmonds_2006A.ICSHMO.pdf
So some background on general definitions:
Bomb cyclogenesis is the formation of an "extratropical area of low pressure in which the central barometric pressure drops at least 24 millibars in 24 hours."
A classic bomb event was the 'Perfect storm' that occured in the 1990's: the rapid deepening of pressure within the region of the low pressure system commonly results in Hurricane force wind speeds, and strong frontal formation. Intriguingly many of the severe storm situations we encounter when chasing are due to events such as these. The particular system which forms the basis of this study is the event 27th March 2007 10am EST, where a rapidly deepening cyclone formed in the Australian Bight possibly due to interaction and moist inflow from TC Kara.
So as I progress Ill let you all know how it goes, and hopefully have a paper at the end of it.
John
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Sounds very interesting John - look forward to reading more. Some of the MSL charts from the BoM archives of the event under study:
(http://www.bom.gov.au/archive/charts/2007/03/IDX0102.200703260600.gif)
(http://www.bom.gov.au/archive/charts/2007/03/IDX0102.200703261800.gif)
(http://www.bom.gov.au/archive/charts/2007/03/IDX0102.200703270600.gif)
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Sorry John, but for some reason, my browser is saying your pics had been altered or deleted - maybe try again.
Big Pete
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John - it shouldn't matter if people are posting - they certainly are reading it. Keep in mind your understanding of meteorology is quite advanced compared to many of us :) I don't know the answer to your question. All I can see is that the pre deepening weather maps look like textbook situations with cold and warm fronts in position to bomb.
regards, Michael
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Go for it John. I'd be interested to know for one! Ok, I do spend a lot more time reading these posts than replying, but normally its because some of the knowledge of those who have studied weather and storms and the like for a long time, baffles and astounds me, and i get a bit gobsmacked! But there are times i comment to these posts like your thread, coz they genuinely interest me and enhance my understanding - just like others on the forum. Also, if i can contribute to help you, I will.
Big Pete
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John,
I also noticed that on the second system, in the second phase, the "bomb" had actually tracked west a little before strengthening further as it headed SE in phase 3. If the trough that triggered the deepening is in play, why does the storm back-track on itself to strengthen?
Big Pete
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Certainly sounds interesting, and when I was younger I had a definite leaning towards studying meteorology but for some reason went electronics instead. I was going to say before I carefully read all the posts that the last system you posted looked similar to what happened in the 1998 Sydney-Hobart. An event that was made more poignant because I am into shortwave radio, and was sitting at home at Gosford listening to all the Mayday calls etc that night it all went sh*t.
I also have a book by one of the journalists who did the analysis for Four Corners afterwards and re-read it recently. Sounds like conditions rapidly worsened - the book mentioned 3 models of weather forecasting from around the world of which the US one (which is typically more aggressive) proved to be the most correct for this event. There is an Australian, European and US model. Up until immediately before the event the European one had proved to be most correct for the previous fortnight.
The main private forecaster for the event is called Roger Badham (with the nickname of "Clouds"). He could be a useful reference for your study. If you haven't seen it the book is "An Extreme Event" by Debbie Whitworth. published by Random House, ISBM 0-0918-4057-0. Apart from the stories of the yachtsman and what happened it contains a reasonably detailed weather analysis as things occurs (though not that technical given the audience it is aimed at). But it shows how the models changed as every 12 hour update came through. Probably still available through ABC shops if not elsewhere.
Obviously the system you have monitored went even deeper into low pressure, but whether that is the low latitudes is well beyond my understanding to comment on. I have an amateur interest in weather these days - what will the next few days bring and will we see storms?
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Congratulations on your H1 honours John - well done! And the project program sounds rather interesting as well - is it meant to simulate what actually happened or use previous data to try predict the event?
Regards,
Jimmy Deguara
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Hi John, are any of the JRA25 datasets available to the public via an interface like NCEP (http://nomad3.ncep.noaa.gov/cgi-bin/pdisp_6p_r1.sh) ?
Your subject is very interesting - looking forward to your presentation at the ASWA conference.
regards, Michael
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Over what date period is the plot for John ? Sorry if you have mentioned this previously.
MB
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Drat - meeting is in Adelaide now I have moved to Sydney. Oh well.
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John
I wouldn't mind getting a hold of your report sometime down the track. You have a good knowledge of these systems, and it might be worth putting out other publications for the educated reader. eg an e-book would be good.
Well done
Big Pete
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I too would like to get a copy of your thesis. Your involvement with TC characteristics would be welcome up here and of great use. I'm keen to read more John so please don't hesitate to send me a copy of it. I've only got the grass-roots knowledge of cyclones technically speaking and your words offer a great educational tool.
Congrats on finishing it - you're a machine!
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Pooh, I was so looking forward to it.
Got anything relating to tropical regions that you skimmed across during your research?
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Congratulations John - no wonder you are thrilled with the results and scholarship !
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A well deserved honour, Sir. The studying along with the passion reaps rewards and congratulations for achieving such a great result. There's no excuse now for not answering all the technical questions you shall now receive!