Storm Australian Severe Weather Forum
Severe Weather Discussion => Tropical Cyclones, Typhoons and Hurricanes Worldwide => Topic started by: Colin Maitland on 12 December 2009, 04:23:35 AM
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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.
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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.
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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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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.
(http://www.bom.gov.au/fwo/IDD65001.gif?1260580763204)
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.
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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
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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!
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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.
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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.
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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.
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The winds are a lot stronger than the warnings are indicating: 187km/h at Troughton Island
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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).
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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
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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.
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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
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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
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Hardly even 24hrs and Laurence is back.
IDW24100
Australian Government Bureau of Meteorology
Western Australia
Media: The Standard Emergency Warning Signal should NOT be used with this
warning.
TOP PRIORITY FOR IMMEDIATE BROADCAST
TROPICAL CYCLONE ADVICE NUMBER 64
Issued at 11:55 am WST on Saturday, 19 December 2009
BY THE BUREAU OF METEOROLOGY
TROPICAL CYCLONE WARNING CENTRE PERTH
A Cyclone WARNING continues for coastal areas from Cape Leveque to Bidyadanga.
A Cyclone WATCH continues for coastal areas from Bidyadanga to De Grey.
At 11:00 am WST Tropical Cyclone Laurence was estimated to be
140 kilometres north of Broome and moving
west northwest at 8 kilometres per hour.
Tropical Cyclone Laurence has rapidly redeveloped after moving off the west
Kimberley coast.
GALES are occurring at offshore islands and may develop along the coast between
Cape Leveque and Beagle Bay this afternoon as the system continues to intensify.
GALES may extend further down the coast to Broome and Bidyadanga later today or
early on Sunday. As the system moves south westwards GALES could extend further
down the coast to De Grey by Monday morning. The system is expected to take a
more southerly track on Monday and then south eastwards towards the north
Pilbara coast on Tuesday.
Heavy rainfall is expected to continue today in coastal parts of the west
Kimberley with 24 hour falls in excess of 100mm possible.
FESA-State Emergency Service advises as a precautionary measure the following
community alerts:
BLUE ALERT: People in the communities from Cape Leveque to Bidyadanga, including
Broome, Beagle Bay, One Arm Point, Djarindjin and Lombadina need to prepare for
cyclonic weather and organise an emergency kit including first aid kit, torch,
portable radio, spare batteries, food and water.
Communities in northern Pilbara should listen for the next advice.
Details of Tropical Cyclone Laurence at 11:00 am WST:
.Centre located near...... 16.7 degrees South 122.3 degrees East
.Location accuracy........ within 20 kilometres
.Recent movement.......... towards the west northwest at 8 kilometres per hour
.Wind gusts near centre... 100 kilometres per hour
.Severity category........ 1
.Central pressure......... 990 hectoPascals
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Silly thing, I know it is following the forecast tracks after it crossed the coast and went back out to sea, but was really hoping it would head inland and give some badly needed moisture to feed into parts of SA and maybe western NSW.
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Laurence has been a interesting cyclone to watch. Maybe they should have called him Cyclone Yo Yo. ;D
Latest data on the storm system has Laurence regenerating of the WA coast and he is expected to make an impact on land near Pilbara as a Cat 4 cyclone around Tuesday.
Data from BOM
The circulation has excellent structure through depth, vertical wind
shear is low and oceanic heat content is high so the system is expected to
rapidly intensify in the next 12-24 hours. Very deep convection is evident about
the centre particularly in the western eye-wall region with tightening curvature
near the centre indicated from Broome radar and latest microwave imagery.
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This indeed has been an interesting Cyclone to track, especially so early.
I'm pretty certain that Laurence is now rapidly intensifying. Early signs of an eye can be seen on IR imagery. On Broome/Port Hedland radar show the eyewall a lot more thick and stable than 12 hours ago, more so in the northeast quadrant.
Edit: Laurence is a strong Category 4 system, and will probably make landfall at that strength, after which it will finally dissipate.
Details of Severe Tropical Cyclone Laurence at 8:00 am WST:
.Centre located near...... 19.0 degrees South 120.4 degrees East
.Location accuracy........ within 20 kilometres
.Recent movement.......... towards the south at 6 kilometres per hour
.Wind gusts near centre... 260 kilometres per hour
.Severity category........ 4
.Central pressure......... 939 hectoPascals
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Laurence is now a CAT 5 system as it approaches the Northern WA coastline.
Latest stats and Data from BOM concerning the storm:
At 11:00 am WST Severe Tropical Cyclone Laurence was estimated to be
75 kilometres north of Wallal and
240 kilometres east northeast of Port Hedland
moving south southeast at 6 kilometres per hour.
Severe Tropical Cyclone Laurence is intensifying as it moves southwards towards the Eighty Mile Beach area of the Pilbara-Kimberley coast. Residents are warned of a period of VERY DESTRUCTIVE winds with gusts to 285 kilometres per hour developing during this afternoon. People in the area are specifically warned of the VERY DANGEROUS STORM TIDE expected as the cyclone centre approaches the coast. Tides may rise significantly above the normal high tide mark with
DAMAGING WAVES and DANGEROUS FLOODING.
Details of Severe Tropical Cyclone Laurence at 11:00 am WST:
.Centre located near...... 19.1 degrees South 120.5 degrees East
.Location accuracy........ within 20 kilometres
.Recent movement.......... towards the south southeast at 6 kilometres per hour
.Wind gusts near centre... 285 kilometres per hour
.Severity category........ 5
.Central pressure......... 929 hectoPascals
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This site (http://www.bom.gov.au/products/IDW60801/IDW60801.94200.shtml) is almost directly in the path of Laurence. Although it's being blasted from the southeast side of the eyewall (the southwest is typically the strongest side with our Cyclones if memory serves me right).
Pressure is down to 952.1hPa.
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Eh, I honestly thought it was the left side for our Cyclones, right side for Northern Cyclones. Learn something new everyday.
Pressure is now at 936. I think the eye is almost over the site at this point.
Edit: Fixed a typo.
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Looking at the obs for Mandora and the radar it looks like it just clipped the east edge of the eye, with Wallal Downs almost the same but on the west side. Max gusts stated so far 204km/hr around 4:35pm.
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As the pressure was dropping, at around 935hPa the wind speed & gusts peaked around 4:35pm 145km/h(77kts)speed 204km/h(110kts)gusts
but then seemed to ease back (still a bit choppy though) around the time of the lowest pressure bettween the 928.8hPa, 928.4hPa readings, to near 106km/h(57kts)wind speed 165km/h(89kts)gusts (5:18pm)then they increased steadily again with the pressure to be at 6:08pm 939.6hPa windspeed 158km/h(85kts)and gusts to 211km/h(114kts) before starting to ease again.
Could that be interpreted as a slice through the eye wall from outer to inner and back out again?
Cheers Paul
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Interesting how the wind direction seemed to go quite random for a while there after about 6pm.
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Laurence is still a Cat 3 cyclone after crossing the coast and continues to head inland (7.15am 22/12/09). He is expected to weaken as he tracks Southeast, but due to the flat terrain in Northern WA his weakening will be "somewhat slower than normal" according to the latest update from BOM.
BOM have stated,
Model guidance indicates that despite increasing shear from 500-200 the low to mid levels will remain coherent and together with the rapid translation this is likely to result in a system capable of producing severe wind gusts and
significant rain a long way across the continent.
It is impressive to observe the track map, if the models hold true, you will notice that approximately 700km inland he is still a cat 1 cyclone. I think you have to go back to the 1978/79 season before you find a cyclone so deep inland. But I can't, at this stage, find if any of the cyclones were able to keep their intensity that many kilometers over land.
The synoptics indicate that Laurence will become a low and track right over the interior to the NSW/VIC coast over the coming next few days
Col
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If I remember right Vance got to within 70km's of Kalgoorlie before being downgraded to a low, but then Vance was a lot bigger system on crossing the coast, your right Col it'll be interesting to see how far Laurence goes relative to it's size.
Paul
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Your right Paul, that is awesome, Cyclone Vance, March 1999
Thanks
Col
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Looks like Laurence didn't quite make it to Giles, now to see how much rain the system produces over the next couple of days..
Cheers
Paul