Author Topic: Hybrid Low (Cyclone "Donald") crosses NSW North Coast : 5 - 9 March 2001  (Read 12973 times)

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Offline Antonio (stormboy)

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A Tasman Sea low, exhibiting every characteristic of a tropical cyclone apart from having a tropical origin, slammed into the NSW North Coast late this afternoon causing widespread wind damage and torrential rain, dramatically worsening an already tense flood situation. The depression formed in the northern Tasman Sea at around 30°S last Sunday morning, and has drifted slowly but steadily W to WNW since then.

The low, with a distinct eye visible on satellite and radar images, crossed the coast near Ballina around 6pm, dropping the pressure at the airport to 992.5hPa. It then moved slowly north close to the coast before moving into SE Qld. Because it has been so slow moving, the low has had time to entrain copious amounts of warm, humid, tropical air down its eastern flank. This, coupled with strong divergence, or outflow, aloft and high vorticity, or rotation imparted by the surrounding atmosphere, at lower levels, has set the scene for a major east coast flood event.

Squally, galeforce winds reached cyclonic speeds, with Evans Head automatic weather station, 30km south of Ballina, recording a top gust of 139km/h at 5.15pm. Around 100 buildings at Yamba, 60km south of Ballina, were damaged, and State Emergency Services attended 350 calls for roof damage and downed trees in the North Coast area. Large trees were snapped off or uprooted near the coast, where the winds were strongest, and 70 power lines were cut, blacking out over 10,000 homes between Kempsey and Ballina. SES advised against all non-essential road travel in the Lismore area because of the extensive storm damage, and the severe winds made travel and work close to impossible for repair crews. Caravan parks were evacuated because of the threat of caravans being overturned, and one man was injured by a falling tree

The news topic is on ASW but i would love any more data, images, track maps etc on this anything at all.
http://www.australianweathernews.com/news/2001/03/20010308.htm

Antonio.

Offline Michael Bath

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Location: Mcleans Ridges, NSW Northern Rivers
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Offline Antonio (stormboy)

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RE: Hybrid Low (Cyclone "Donald") crosses NSW North Coast : 5 - 9 March 2001
« Reply #2 on: 04 November 2010, 10:32:02 AM »
Thanks you MB and John for the links i dont know why but my heart is set out for some reason to find as much info on this event as possible Google has nothing

Antonio.

Offline Antonio (stormboy)

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RE: Hybrid Low (Cyclone "Donald") crosses NSW North Coast : 5 - 9 March 2001
« Reply #3 on: 04 November 2010, 10:33:35 AM »
So i dont get this even though it reached a Cat 2 intensity therefore a cyclone why was it not called a cyclone? was it because it is south of Qld?

Antonio.
« Last Edit: 04 November 2010, 10:46:03 AM by Antonio (stormboy) »

Offline Antonio (stormboy)

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RE: Hybrid Low (Cyclone "Donald") crosses NSW North Coast : 5 - 9 March 2001
« Reply #4 on: 04 November 2010, 10:45:18 AM »
I can see in the map below that it also was out there for quiet a while ( num 19 )

Antonio.

Offline Steven

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RE: Hybrid Low (Cyclone "Donald") crosses NSW North Coast : 5 - 9 March 2001
« Reply #5 on: 04 November 2010, 02:36:38 PM »
So i dont get this even though it reached a Cat 2 intensity therefore a cyclone why was it not called a cyclone? was it because it is south of Qld?

Antonio.

That has been answered (sort of) here.

Quote
Press and political questions were raised as to why the Bureau of Meteorology had not tracked Thursday's damaging low pressure system as it would have a cyclone. As reported in AWN for Thursday, the system exhibited all the characteristics of a category 1 or 2 cyclone, except that it lacked a tropical origin. Ballina MP Don Page pressed for an overhaul of the BoM's classification of severe weather events. He was quoted by the ABC as saying that, had the system developed in tropical waters, it would have been classified as a cyclone, and its strength and movement more closely monitored.

I think you will find that once south of a certain latitude, they aren't given a name as they are simply referred to as "intense lows". Weather forecasters are more cautious of low pressure systems in warmer waters as they are the most likely scenarios for cyclones developing. Besides, the naming scheme for cyclones is wearing thin and they probably only want to reserve them for major cyclones threatening coastal communities in the north.

By the way, this thread's title could do with a rename. It needs to include the range of dates and places it affected.

Offline Antonio (stormboy)

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RE: Hybrid Low (Cyclone "Donald") crosses NSW North Coast : 5 - 9 March 2001
« Reply #6 on: 04 November 2010, 03:31:05 PM »
But it was a """Cyclone""" wasnt it? technically?

Antonio.

Offline Antonio (stormboy)

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RE: Hybrid Low (Cyclone "Donald") crosses NSW North Coast : 5 - 9 March 2001
« Reply #7 on: 04 November 2010, 06:45:09 PM »
That was very good reading thanks

Antonio.

Offline Colin Maitland

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RE: Hybrid Low (Cyclone "Donald") crosses NSW North Coast : 5 - 9 March 2001
« Reply #8 on: 05 November 2010, 03:46:02 AM »
Hi Antonio,
Believe it or not I only noticed this thread.
John's answer has summed it up excellently. Through out some threads I noticed you are very curious over lows and Hpa and gaining an understanding of them. It does not matter how old or how long you have been observing or studying you learn something new everyday, which is exciting.  I thought you might enjoy these links.

http://www.islandnet.com/~see/weather/almanac/arc2006/alm06jan.htm

http://www.bom.gov.au/weather/nsw/sevwx/facts/ecl.shtml

http://en.wikipedia.org/wiki/Tropical_cyclone_scales

http://www.australiasevereweather.com/forum/general-weather-all-topics-that-are-not-current-severe-weather-should-be-posted-here/tropical-lows-what-are-they/

Just a bit of light reading  ;) you might enjoy. It can also lead you to other sites by  prompting questions you may have.

PS. If you find some other goodies don't forget to share them with us. I believe, as we are still "relatively young" in the  advancement of computer technology,( which is accelerating everyday) as compared to the stream of time, ( hopefully everyone knows what I mean by that)  we will find  new theories or have to correct what was once thought to be 100%, while some will stay as per.

Cheers

Col
« Last Edit: 05 November 2010, 05:34:45 AM by Colin Maitland »

Offline Michael Bath

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RE: Hybrid Low (Cyclone "Donald") crosses NSW North Coast : 5 - 9 March 2001
« Reply #9 on: 05 November 2010, 04:21:27 AM »
There has actually been a recently published paper on this event by a friend of mine.
http://journals.ametsoc.org/doi/abs/10.1175/2009MWR3220.1

The official diagnosis is that it was a warm-cored system, and underwent a tropical transition from what was originally cold cored.

John - that report requires a login and I suspect a subscription.

Luke Garde talked about this event at the ASWA conference in Melbourne last year.

I'm sure I've got some radar and other stuff somewhere.... will check
Location: Mcleans Ridges, NSW Northern Rivers
Australian Severe Weather:   http://australiasevereweather.com/
Lightning Photography:   http://www.lightningphotography.com/
Early Warning Network: http://www.ewn.com.au
Contact: Michael Bath

Offline Antonio (stormboy)

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John - that report requires a login and I suspect a subscription.

Luke Garde talked about this event at the ASWA conference in Melbourne last year.

I'm sure I've got some radar and other stuff somewhere.... will check


Michael i would soo soo much love any radar for this event i really would also Colin thank you very much for the links i will read these tonight when i get back home.

Antonio.

Offline Antonio (stormboy)

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Re: Hybrid Low (Cyclone "Donald") crosses NSW North Coast : 5 - 9 March 2001
« Reply #11 on: 05 November 2010, 11:21:35 AM »
This reading is excellent :) so now i have a much better understanding at least also as stated above if anyone at all has even 1% information on the event please do share it is most fascinating to me and i want all the info i can get on it :)


EDIT:

some info on its flooding here http://www.downunderchase.com/duc/storm-chase-reports/2000-2001/73-march-9-2001-brisbane-flash-flood-event.html

Antonio.

Offline Antonio (stormboy)

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Re: Hybrid Low (Cyclone "Donald") crosses NSW North Coast : 5 - 9 March 2001
« Reply #12 on: 05 November 2010, 11:23:49 AM »
I found some related info on the flooding from this event it is good reading too

http://www.downunderchase.com/duc/storm-chase-reports/2000-2001/73-march-9-2001-brisbane-flash-flood-event.html

Antonio.

Offline Michael Bath

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Re: Hybrid Low (Cyclone "Donald") crosses NSW North Coast : 5 - 9 March 2001
« Reply #13 on: 06 November 2010, 04:53:11 AM »
Found the radar amongst my archives, though this may have been placed online in the past somewhere.

I'm pretty sure my power was out late evening so the loop stops as the eye is passing inland. I remember it passed right over my place at McLeans Ridges and noted:

Quote
Heavy falls last night with some lightning. Heavy falls amongst lighter rain all day with strengthening SSW winds. Cyclonic winds from just after 3pm as TC eye was east of Ballina. Wind gusts over 70knots and torrential rain. Rain eased as the eye crossed coast around 7pm. Wind direction varied but stayed strong with rain easing then clearing later.



Also a link to the 128km scale radar:

http://australiasevereweather.com/storm_news/2001/radar/20010308_grafton128.gif
« Last Edit: 06 November 2010, 04:58:27 AM by Michael Bath »
Location: Mcleans Ridges, NSW Northern Rivers
Australian Severe Weather:   http://australiasevereweather.com/
Lightning Photography:   http://www.lightningphotography.com/
Early Warning Network: http://www.ewn.com.au
Contact: Michael Bath

Offline Antonio (stormboy)

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Re: Hybrid Low (Cyclone "Donald") crosses NSW North Coast : 5 - 9 March 2001
« Reply #14 on: 06 November 2010, 11:51:29 AM »
Michael thanks so so so much for finding a radar it is soo intense!

Thanks again

Antonio.