Author Topic: 1st Low of the 2009/2010 Australian season : Tropical Cyclone Laurence  (Read 16371 times)

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Offline Colin Maitland

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Potential Cyclones:
Bom have issued their first watch for the 2009/2010 Australian season

At 3:30 pm CST a developing Tropical Low, 1002 hPa, was located in the Arafura
Sea, near 10.2S 134.0E, about 170 kilometres north northeast of Goulburn Island.
The low is expected to move west or west southwest during the next three days
into the Timor Sea and may develop into a tropical cyclone during the weekend.
Refer to latest TC Advice issued by Darwin TCWC.

Likelihood of a tropical cyclone being in the Northern Region on:
Friday: low,
Saturday: moderate,
Sunday: high.


« Last Edit: 12 December 2009, 04:29:13 AM by Colin Maitland »

Offline Colin Maitland

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RE: 1st Low of the 2009/2010 Australian season : Tropical Cyclone Laurence
« Reply #1 on: 13 December 2009, 02:57:34 AM »
Predicted track map for the tropical low that is expected to turn into a Cat 1 storm by the 14th of Dec 09 (if not earlier).


Col.



Offline Michael Bath

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RE: 1st Low of the 2009/2010 Australian season : Tropical Cyclone Laurence
« Reply #2 on: 13 December 2009, 06:03:54 AM »
The earlier forecast maps had the low staying well north of Darwin - funny how it ended up right on Darwin!  Wind gusts have been 85ks (45kts) in all the warnings so far.
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Offline Mike

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RE: 1st Low of the 2009/2010 Australian season : Tropical Cyclone Laurence
« Reply #3 on: 13 December 2009, 09:19:48 AM »
Yeah it's been a bit wet here lately.  Already we've reached 130mm in the 24 hours. A few gusty squalls last night with some downed trees and flooding of the usual roads due to being low level.  All the catchments are full and the golf course behind my place is under water.  The low is expected to reach CAT3 by mid-week over the NW WA area.  Low Level Circulation is good with low shear and good storm convection in the bands.  SST's are favorable also.  The low has done the monsoon wobble as they do since picked up and sat over Darwin around 4am this morning.  I was still up enjoying it all as one does!  Circulating rain bands are visible with ground hugging black areas with the heavier precip.

There's been some banter amongst the other weathernuts up here about how deplorable the BOM have been tracking it and why they did not issue a watch for us given the slight damage and flooding...well they don't understand that these systems have a mind of their own and as of 3am this morning it was still moving SW and above us. If you see the track map it shows the predictable wave track they usually take when the steering winds push them westward..the bureau, regardless of whether they are forecasting and not storm chasers has no relevance to issue watches and panic everyone.  It was still 1005-1002hpa as it moved/moves over us so obviously it would have squalls associated with it with storms forming within the bands.  Kinda gets me very irrate when people want to mass-bash publicly the bureau for something they have no real control over.  They issued a severe weather warning noting flooding and possible 100kmh winds, but this was not for Darwin, but the Darwin-Daly region to our west.  Of course the low would produce such weather - it's developing into a cyclone for Pete's sake! It's just a little disorganized as it moves over us being close to land, once it enters the warmer open ocean then it will ramp up.

Some thunder being heard at the moment (1:40pm) but tis typical of these bands with embedded storm activity.  Probably expect a flang perhaps but tis grey, wet, constant moderate rain and only 25C Brrrr!  Will post some photos of some of the scenery (or lack of) soon.




SEVERE WEATHER WARNING
for Locally Damaging Winds and Heavy Rainfall
for people in the Darwin-Daly District
Issued at 11:00 am CST Saturday 12 December 2009

Synoptic Situation: A TROPICAL LOW 1001 hPa is located on the coast near Darwin.
At 9:30 am CST it was near latitude 12.5S, longitude 130.7E, about 20 kilometres
west southwest of Darwin, moving southwest at 11 kilometres per hour. The low is
expected to develop into a tropical cyclone as it moves into the Timor Sea later
today.

Locally damaging wind gusts up to 100 km/h are possible in the Darwin-Daly
District today. Heavy rain in the Darwin-Daly District is expected to cause
localised flooding of low-lying areas today and on Sunday.
Darwin, Northern Territory.
StormscapesDarwin.com
Lightning Research 2010/14

Offline Colin Maitland

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RE: 1st Low of the 2009/2010 Australian season : Tropical Cyclone Laurence
« Reply #4 on: 13 December 2009, 09:47:48 AM »
I was trying hard this morning to choose the right words of how those survivors of Cyclone Tracey of 1974 must be feeling and the flash backs they may be enduring, due to the timing of this low, of that horrifying Christmas eve disaster and how their lives changed forever. Sometimes you cant find those words. Fortunately, at this stage it appears the storm will continue away from Darwin.

The posted Sat image is courtesy of Day image,it shows a well defined low level circulation center with convection building both along the Southern and Southwestern extent of the center. Conditions seem very favourable for this storm to continue building and as the current track maps indicate to a higher Cat storm.

Col
« Last Edit: 13 December 2009, 01:29:58 PM by Colin Maitland »

Offline Mike

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RE: 1st Low of the 2009/2010 Australian season : Tropical Cyclone Laurence
« Reply #5 on: 13 December 2009, 11:44:44 AM »
Those that endured Tracy in 1974, Colin are pretty well up to speed with such things and they are quite knowledgeable when it come as to these lows. In reality, if there was any sustainable life threatening situation that could have arose re an earlier formation or change in direction those that endured Tracy would not stay in town.  The media has been quite good with giving us a heads up on when it formed as a low and found out it was going to cyclone status later in the days, but as mentioned this low was picked up by the usual authorities overseas fairly early...probably why a select few are jumping up and down claiming 'We saw it first - why didn't BoM!'  Priorities & common sense I suspect are in order.

Anyway...Updating the weather here, it's gone quite again as the gap in the rain bands comes through.  Still a lot more to come but as the days go by it will be back to the arvo storm for us.  ..Oh...that storm we had Thursday night to which I was at work and not being able to chase but viewed all of it..the storm produced 1700+ strikes in its life ycle in the city alone and is some record now I have heard re that figure for a storm in the city...was quite a sight and I've never seen anything so intense since I arrived in Darwin in 2002!  Mind blowing lightning..

Heading out rural tonight to catch up with friends and will be taking the obligatory camera etc just in case!
Darwin, Northern Territory.
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Lightning Research 2010/14

Offline Shaun Galman

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RE: 1st Low of the 2009/2010 Australian season : Tropical Cyclone Laurence
« Reply #6 on: 13 December 2009, 01:38:42 PM »
Hi guys,

Seems the current forecast models show this low to be moving inland through W.A. on Wednesday 16th or Thursday the 17th of December and on down towards the southern states by Friday-ish.

I really hope this holds true. Besides the obvious drought issues I really think we need some decent ground moisture to drive a few storms or we will be in for an ordinary season to say the least, particularly out here in the W/NW parts of N.S.W.

Best of luck with the lightning photos Mike! Grab a few rippers for us to drool over lol. ;D

Kindest regards,
Shauno.
Chasing Region: Lightning Ridge. N.S.W.
Website: www.ridgelightning.com

Offline Colin Maitland

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RE: 1st Low of the 2009/2010 Australian season : Tropical Cyclone Laurence
« Reply #7 on: 14 December 2009, 06:57:44 AM »
The tropical low has formed into Tropical cyclone  Laurence

Update from BOM

TROPICAL CYCLONE ADVICE NUMBER 15  
Issued by the BUREAU OF METEOROLOGY, DARWIN
at 11:00 am CST [9:30 am WST] Sunday 13 December 2009

A Cyclone WARNING is now current for coastal areas from Mitchell Plateau to
WA/NT Border.

A Cyclone WATCH continues for coastal areas from Kuri Bay to Mitchell Plateau.

At 9:30 am CST [8:00 am WST] Tropical Cyclone Laurence, Category 1 was estimated
to be 80 kilometres north of Port Keats and 310 kilometres east northeast of
Kalumburu and moving southwest at 7 kilometres per hour.

Tropical cyclone Laurence is expected to move westward into the Timor Sea, and
approach the north Kimberley coast tonight.


Offline Colin Maitland

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Re: 1st Low of the 2009/2010 Australian season : Tropical Cyclone Laurence
« Reply #8 on: 16 December 2009, 01:41:18 AM »
An update on tropical Cyclone Laurence:

The track map indicates that Laurence will cross the WA coast on Wednesday as a Cat.2 cyclone

Warning from BOM

At 3:30 am CST [2:00 am WST] Tropical Cyclone Laurence, Category 1 was estimated
to be 120 kilometres north of Kalumburu and 195 kilometres north northeast of
Mitchell Plateau and moving west at 10 kilometres per hour.

Tropical Cyclone Laurence is expected to curve southwest close to the northwest
Kimberley coast in Western Australia.

GALES with gusts to 110 kilometres per hour are currently being experienced over
the north Kimberley coast between Troughton Island and the mouth of the King
George River. These winds are expected to extend further southwest along the
coast, reaching as far as Cockatoo Island on Wednesday morning. GALES may extend
further southwest as far as Beagle Bay by Thursday. If the cylcone takes a more
southerly track, GALES may extend further inland during today. DESTRUCTIVE WINDS
with gusts to 130 kilometres per hour may develop near Troughton Island later
today, and may extend southwest along the coast as far as Kuri Bay by Wednesday
morning.

HEAVY RAIN is expected to continue over the north Kimberley region today,
extending into the western Kimberley during today and Wednesday.


I am not familiar with the area up there, so I do not know if it is vastly populated or if it is structured around many small communities. I will need to research that.

 

Offline Michael Bath

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Re: 1st Low of the 2009/2010 Australian season : Tropical Cyclone Laurence
« Reply #9 on: 16 December 2009, 05:34:31 AM »
The winds are a lot stronger than the warnings are indicating: 187km/h at Troughton Island



Location: Mcleans Ridges, NSW Northern Rivers
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Offline Carlos E

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Re: 1st Low of the 2009/2010 Australian season : Tropical Cyclone Laurence
« Reply #10 on: 16 December 2009, 06:03:27 AM »
I was just about to post that as well Michael.

Laurence is a Category 3 Cyclone, not the weak end of a Category 2 like BoM are saying in the warnings.

This is the problem with small Cyclones + Satellite predictions. They can be so far off. I remember the same thing happened with Cyclone George (although George wasn't small, but the wind predictions compared to actual observations were almost identical to what has happened here).

Offline Michael Bath

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Re: 1st Low of the 2009/2010 Australian season : Tropical Cyclone Laurence
« Reply #11 on: 16 December 2009, 09:34:46 AM »
Further to that, the next few hours of observations show the eye was pretty much centred over the island at 9am local time.

VIS imagery has a cluster of thunderstorms corresponding to the maximum wind gusts

Location: Mcleans Ridges, NSW Northern Rivers
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Offline Carlos E

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Re: 1st Low of the 2009/2010 Australian season : Tropical Cyclone Laurence
« Reply #12 on: 16 December 2009, 11:37:56 PM »
Further to that, the next few hours of observations show the eye was pretty much centred over the island at 9am local time.

VIS imagery has a cluster of thunderstorms corresponding to the maximum wind gusts

I was wondering what was going on when the pressure dropped to 982 the first time, then went back up, then down again when the wind eased (which as you said was the eye). Just found it odd for the pressure to fall and then rise again before the eye itself was even over the Island.

Although I find this storm in general to be strange. I'm still quite shocked its developed itself into a Category 4 when the entirety of its life has been almost on top of the coast. I would assume the small size of the system is what's helping it to do this.

Offline Colin Maitland

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Re: 1st Low of the 2009/2010 Australian season : Tropical Cyclone Laurence
« Reply #13 on: 17 December 2009, 03:24:07 AM »
I like the JTWC data on Laurence where it states

"ANIMATED INFRARED IMAGERY SHOWS THE DEVELOPMENT OF A PINHOLE EYE WHILE A 151730Z AMSR-E MICROWAVE IMAGE DEPICTS THE MIDGET SIZE OF THE SYSTEM"

BOMs update on the stats

Details of Severe Tropical Cyclone Laurence at 5:00 am WST:
.Centre located near...... 15.2 degrees South 124.3 degrees East
.Location accuracy........ within 30 kilometres
.Recent movement.......... towards the southwest at 11 kilometres per hour
.Wind gusts near centre... 260 kilometres per hour
.Severity category........ 4
.Central pressure......... 944 hectoPascals


Offline Mathew Townsend

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Re: 1st Low of the 2009/2010 Australian season : Tropical Cyclone Laurence
« Reply #14 on: 17 December 2009, 11:30:18 AM »
Shes a beast!!!

IDW24100
Australian Government Bureau of Meteorology
Western Australia

Media: Transmitters serving the area between Kuri Bay and Beagle Bay are
requested to USE the Standard Emergency Warning Signal before broadcasting the
following warning.


TOP PRIORITY FOR IMMEDIATE BROADCAST

TROPICAL CYCLONE ADVICE NUMBER 40
Issued at 12:00 pm WST on Wednesday, 16 December 2009
BY THE BUREAU OF METEOROLOGY
TROPICAL CYCLONE WARNING CENTRE PERTH

A Cyclone WARNING is current for coastal areas from Kuri Bay to Beagle Bay and
adjacent inland parts.

A Cyclone WATCH has been declared for Beagle Bay to Bidyadanga and extending
inland towards Fitzroy Crossing.

At 11:00 am WST Severe Tropical Cyclone Laurence, Category 5 was estimated to be
55 kilometres southwest of Kuri Bay and
170 kilometres north northeast of Derby and
moving south southwest at 11 kilometres per hour.

Severe Tropical Cyclone Laurence is a small but very intense tropical cyclone
having VERY DESTRUCTIVE WINDS with gusts to 285 kilometres per hour close to the
cyclone centre. VERY DESTRUCTIVE wind gusts are possible on the coast south of
Kuri Bay during this afternoon and evening.

GALES with gusts to 100 kilometres per hour may extend further southwest along
the coast, reaching Cockatoo and Koolan Islands during this afternoon and
evening. Should the centre pass close by VERY DESTRUCTIVE winds are possible
during the afternoon and evening. GALES, and possibly DESTRUCTIVE winds may
extend to Derby and Beagle Bay early Thursday morning.

HEAVY RAIN is expected to continue over the north and west Kimberley. Daily
rainfall totals in excess of 100mm are possible near the coast with totals
decreasing further inland.

FESA-State Emergency Service advises of the following community alerts:
RED ALERT: People in or near the communities of Koolan Island and Cockatoo
Island need to go to shelter immediately.
YELLOW ALERT: People in or near the communities of Cape Leveque, One Arm Point,
Djarindjin, Lombadina and Derby should be taking action.
ALL CLEAR WITH CAUTION: People in or near Mitchell Plateau and Kuri Bay wind and
storm surge dangers have passed but you need to take care to avoid the dangers
caused by damage.

Details of Severe Tropical Cyclone Laurence at 11:00 am WST:
.Centre located near...... 15.9 degrees South 124.2 degrees East
.Location accuracy........ within 35 kilometres
.Recent movement.......... towards the south southwest at 11 kilometres per hour
.Wind gusts near centre... 285 kilometres per hour
.Severity category........ 5
.Central pressure......... 934 hectoPascals