Tropical Cyclone Narelle

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Re: Tropical Cyclone Narelle

Postby wiz » Sat Jan 12, 2013 3:58 pm

What drugs is the JTWC on? Update has just came out and it says:

72 HRS, VALID AT:
150600Z --- 32.3S 111.2E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
BECOMING EXTRATROPICAL

70knot gusts would be a cat 2 prior to becoming extratropical to the west of Perth. Not a chance!

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Re: Tropical Cyclone Narelle (Technical Discussion Only)

Postby brayden » Sat Jan 12, 2013 6:02 pm

TROPICAL CYCLONE FORECAST TRACK MAP

Severe Tropical Cyclone Narelle

Issued at 5:45 pm WST Saturday 12 January 2013. Refer to Tropical Cyclone Advice Number 23.

Image

Remarks:

Severe Tropical Cyclone Narelle is expected to move to the south southwest and pass west of the Northwest Cape on Sunday.

Gales with gusts to 100 kilometres per hour may develop in coastal areas between Onslow and Cape Cuvier on Sunday. Gales may extend south to Denham late on Sunday or Monday if the cyclone takes a track closer to the coast than expected.

Tides along the west Pilbara coast are likely to rise above the normal high tide mark with flooding of low lying coastal areas possible. Higher than normal tides should extend along the west coast overnight tonight and continue into early next week.

DFES-State Emergency Service advises of the following community alerts:

BLUE ALERT: Coastal and island communities from Onslow to Coral Bay including Exmouth should be taking precautions.
Communities between Coral Bay and Denham should listen for the next advice.

The next Forecast Track Map will be issued by 9:00 pm WST Saturday


TOP PRIORITY FOR IMMEDIATE BROADCAST

TROPICAL CYCLONE ADVICE NUMBER 23
Issued at 5:43 pm WST on Saturday 12 January 2013


A Cyclone WARNING continues for coastal areas from Onslow to Cape Cuvier,
including Exmouth.

A Cyclone WATCH continues for coastal areas from Cape Cuvier to Denham,
including Carnarvon.

At 5:00 pm WST Severe Tropical Cyclone Narelle, Category 4 was estimated to be
375 kilometres northwest of Exmouth and
640 kilometres north northwest of Carnarvon and
moving south southwest at 10 kilometres per hour.

Severe Tropical Cyclone Narelle is expected to move to the south southwest and
pass west of the Northwest Cape on Sunday.

Gales with gusts to 100 kilometres per hour may develop in coastal areas
between Onslow and Cape Cuvier on Sunday. Gales may extend south to Denham late
on Sunday or Monday if the cyclone takes a track closer to the coast than
expected.

Tides along the west Pilbara coast are likely to rise above the normal high
tide mark with flooding of low lying coastal areas possible. Higher than normal
tides should extend along the west coast overnight tonight and continue into
early next week.

DFES-State Emergency Service advises of the following community alerts:

BLUE ALERT: Coastal and island communities from Onslow to Coral Bay including
Exmouth should be taking precautions.
Communities between Coral Bay and Denham should listen for the next advice.

Details of Severe Tropical Cyclone Narelle at 5:00 pm WST:
.Centre located near...... 19.5 degrees South 111.6 degrees East
.Location accuracy........ within 35 kilometres
.Recent movement.......... towards the south southwest at 10 kilometres per hour
.Wind gusts near centre... 250 kilometres per hour
.Severity category........ 4
.Central pressure......... 938 hectoPascals

The next advice will be issued by 9:00 pm WST Saturday 12 January.

Cyclone advices and State Emergency Service Community Alerts are available by
dialling 1300 659 210
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Re: Tropical Cyclone Narelle

Postby von-Kármán » Sat Jan 12, 2013 8:33 pm

From 2.5hrs ago ... structure has vanished, I'm actually surprised the BoM still have her at 4
Image

Technical update is claiming poor eastern outflow is the cause of the decline in strength. That my be, but the result of that was influx of dry air which killed convection and collapsed the eyewall structure.

What caused the poor outflow though? Shear does not appear that bad unless it was a localised meso-beta scale phenomena not picked up on the shear maps? Possible I guess ...

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Re: Tropical Cyclone Narelle

Postby Fu Manchu » Sat Jan 12, 2013 10:10 pm

It was my understanding that there was high upper shear to its South yesterday. Would that have played a roll? i.e.. It moved closer or into that higher shear environment?

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Tropical Cyclone Narelle

Postby Fu Manchu » Sat Jan 12, 2013 10:56 pm

Karl Brunckhorst says its due to higher shear rather than the dry air.

"@gsdavo1975 @thewawg more to do with increasing shear, and sea surface temps below 26 that far south."

So I guess that clarifies it.

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Re: Tropical Cyclone Narelle (Technical Discussion Only)

Postby brayden » Sun Jan 13, 2013 6:12 am

TROPICAL CYCLONE FORECAST TRACK MAP

Severe Tropical Cyclone Narelle

Issued at 5:43 am WST Sunday 13 January 2013. Refer to Tropical Cyclone Advice Number 27.

Image


Remarks:

Severe Tropical Cyclone Narelle is expected to move to the south southwest and pass west of the Northwest Cape during Sunday.

If the cyclone moves on a track which brings it closer to the coast then gales with gusts to 100 kilometres per hour may develop in coastal areas between Onslow and Cape Cuvier during Sunday and may extend south to Carnarvon late Sunday. Gales may extend down to Denham early Monday.

Tides along the west Pilbara coast are likely to rise above the normal high tide mark with flooding of low lying coastal areas possible. Higher than normal tides should extend along the west coast Sunday morning and continue into early next week.

DFES-State Emergency Service advises of the following community alerts:

BLUE ALERT: Coastal and island communities from Onslow to Coral Bay including Exmouth should be taking precautions.
Communities between Coral Bay and Denham should listen for the next advice.

Name: Severe Tropical Cyclone Narelle

Details:
Time (WST) Intensity Category Latitude (decimal deg.) Longitude (decimal deg.) Estimated Position Accuracy (km)
0hr 5 am January 13 3 20.8S 111.0E 55
+6hr 11 am January 13 3 21.6S 110.5E 80
+12hr 5 pm January 13 3 22.4S 110.1E 100
+18hr 11 pm January 13 3 23.2S 109.6E 125
+24hr 5 am January 14 2 24.3S 109.2E 145
+36hr 5 pm January 14 2 26.8S 108.8E 180
+48hr 5 am January 15 1 29.0S 108.5E 220

The next Forecast Track Map will be issued by 9:00 am WST Sunday


TOP PRIORITY FOR IMMEDIATE BROADCAST

TROPICAL CYCLONE ADVICE NUMBER 27
Issued at 5:40 am WST on Sunday 13 January 2013


A Cyclone WARNING is current for coastal areas from Onslow to Carnarvon,
including Exmouth and Carnarvon..

A Cyclone WATCH continues for coastal areas from Carnarvon to Denham..

At 5:00 am WST Severe Tropical Cyclone Narelle, Category 3 was estimated to be
350 kilometres west northwest of Exmouth and
530 kilometres north northwest of Carnarvon and
moving south southwest at 13 kilometres per hour.

Severe Tropical Cyclone Narelle is expected to move to the south southwest and
pass west of the Northwest Cape during Sunday.

If the cyclone moves on a track which brings it closer to the coast then gales
with gusts to 100 kilometres per hour may develop in coastal areas between
Onslow and Cape Cuvier during Sunday and may extend south to Carnarvon late
Sunday. Gales may extend down to Denham early Monday.

Tides along the west Pilbara coast are likely to rise above the normal high
tide mark with flooding of low lying coastal areas possible. Higher than normal
tides should extend along the west coast Sunday morning and continue into early
next week.

DFES-State Emergency Service advises of the following community alerts:

BLUE ALERT: Coastal and island communities from Onslow to Coral Bay including
Exmouth should be taking precautions.
Communities between Coral Bay and Denham should listen for the next advice.

Details of Severe Tropical Cyclone Narelle at 5:00 am WST:
.Centre located near...... 20.8 degrees South 111.0 degrees East
.Location accuracy........ within 55 kilometres
.Recent movement.......... towards the south southwest at 13 kilometres per hour
.Wind gusts near centre... 205 kilometres per hour
.Severity category........ 3
.Central pressure......... 953 hectoPascals

The next advice will be issued by 9:00 am WST Sunday 13 January.

Cyclone advices and State Emergency Service Community Alerts are available by
dialling 1300 659 210
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Re: Tropical Cyclone Narelle

Postby brayden » Sun Jan 13, 2013 6:33 am

Fu Manchu wrote:The view from Exmouth
Photo from @GianDP
Gian De Poloni who is an ABC NW reporter.
Image


Hey Fu, that looks like they were on the hill with the lighthouse west of the Lighthouse Caravan Park, its a fair way north of Exmouth (http://goo.gl/maps/G18vC). There's an old frame for where the WW2 radar used to sit and sandbags. Got to have a look at the place when I did a stint at Learmonth BOM office. Also a sandbag pillbox at the Ap, no doubt some other WW2 things around.

Back to Narelle, yeah its deff. increasing shear and the cooler SST she is going in to.
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Tropical Cyclone Narelle

Postby Fu Manchu » Sun Jan 13, 2013 8:59 am

It's a good caravan Park near the lighthouse.
Was hoping to see some better surf in that. There's a break there/near there that handles pretty much any swell size according to locals.

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Re: Tropical Cyclone Narelle

Postby von-Kármán » Sun Jan 13, 2013 9:03 am

Fu Manchu wrote:Karl Brunckhorst says its due to higher shear rather than the dry air.

"@gsdavo1975 @thewawg more to do with increasing shear, and sea surface temps below 26 that far south."

So I guess that clarifies it.

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Partly, but the shear dropped off again just as she began to deteriorate. The shear to the east when the convection started breaking down was not that significant (10-15kts). You can clearly see a sliver of much dryer air sucked into the eye, killing the (at first) North eastern, then eastern eyewalls. It happened very quickly, over about 6 hours between 00:00Z and 06:00Z ... quicker than the shear environment changed. Seems too coincidental

Yes subsequent deterioration (post 06:00Z) was certainly helped by higher shear to the east and south, but the initial deterioration was thanks to dry air IMHO. right now she's being destroyed by shear.

Anyway

Look at the sequence below
Image

Image
Image
Image
Image
Image
Image
Image
Image

To me those WV images seem pretty damning

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Re: Tropical Cyclone Narelle (Technical Discussion Only)

Postby brayden » Sun Jan 13, 2013 10:03 am

TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by PERTH TROPICAL CYCLONE WARNING CENTRE
at: 0037 UTC 13/01/2013

Name: Severe Tropical Cyclone Narelle
Identifier: 05U
Data At: 0000 UTC
Latitude: 21.2S
Longitude: 111.0E
Location Accuracy: within 30 nm [55 km]
Movement Towards: south southwest [198 deg]
Speed of Movement: 7 knots [14 km/h]
Maximum 10-Minute Wind: 75 knots [140 km/h]
Maximum 3-Second Wind Gust: 105 knots [195 km/h]
Central Pressure: 960 hPa
Radius of 34-knot winds NE quadrant: 120 nm [220 km]
Radius of 34-knot winds SE quadrant: 120 nm [220 km]
Radius of 34-knot winds SW quadrant: 120 nm [220 km]
Radius of 34-knot winds NW quadrant: 120 nm [220 km]
Radius of 48-knot winds NE quadrant: 55 nm [100 km]
Radius of 48-knot winds SE quadrant: 55 nm [100 km]
Radius of 48-knot winds SW quadrant: 55 nm [100 km]
Radius of 48-knot winds NW quadrant: 55 nm [100 km]
Radius of 64-knot winds: 25 nm [45 km]
Radius of Maximum Winds: 20 nm [35 km]
Dvorak Intensity Code: T4.0/4.5/W1.5/24HRS STT:W0.5/6HRS
Pressure of outermost isobar: 1000 hPa
Radius of outermost closed isobar: 220 nm [405 km]
Storm Depth: Deep
FORECAST DATA
Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure
[UTC] : degrees : nm [km]: knots[km/h]: hPa
+12: 13/1200: 22.8S 110.3E: 055 [100]: 065 [120]: 966
+24: 14/0000: 25.0S 109.6E: 080 [145]: 055 [100]: 974
+36: 14/1200: 27.4S 109.2E: 100 [180]: 045 [085]: 979
+48: 15/0000: 29.9S 109.2E: 120 [220]: 035 [065]: 985
+60: 15/1200: 32.0S 110.7E: 140 [255]: 030 [055]: 990
+72: 16/0000: 35.0S 114.9E: 155 [290]: 025 [045]: 995

REMARKS:
Severe Tropical Cyclone Narelle has continued to show a weakening trend during
the early hours of Sunday morning with the effects of cooler ocean temperatures
evident. North easterly shear has reduced to around 10 knots at 18 UTC. Shear is
expected to remain low tomoderate before westerly shear increases on Monday.

Dvorak DT estimates have fallen to 4.0 with the CI held at 4.5. ADT, AMSU and
SATCON are in agreement and final intensity estimate is 75 knots [10-min mean].

Weakening is expected to continue due to cooler SSTs, and accelerate on Monday
as the system is affected by westerly shear. Narelle is likely to remain a
cyclone until Tuesday when it should weaken below cyclone strength well off the
west coast.

Expected motion is generally to the south southwest on Sunday and Monday. The
greatest risk period for gales on the coast is during Sunday in the
Exmouth-Ningaloo area. There is still sufficient uncertainty on how far off the
coast Narelle will be on Monday to maintain a precautionary watch for west
coastal areas south to Denham.

Higher than normal tides are likely about the west Pilbara coast on Sunday, with
a shelf wave moving down the west coast likely to push tides above the highest
astronomical tide at least towards Shark Bay.

Although widespread heavy rain is not expected in the west Pilbara, upslide to
the southeast of the cyclone may bring some rain to the Gascoyne and southern
parts of the state from Sunday to Tuesday.

Copyright Commonwealth of Australia
==
The next bulletin for this system will be issued by: 13/0700 UTC by Perth TCWC.
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Re: Tropical Cyclone Narelle (Technical Discussion Only)

Postby brayden » Sun Jan 13, 2013 12:07 pm

TOP PRIORITY FOR IMMEDIATE BROADCAST

TROPICAL CYCLONE ADVICE NUMBER 29
Issued at 11:34 am WST on Sunday 13 January 2013


A Cyclone WARNING is current for coastal areas from Exmouth to Denham.
The Cyclone WARNING for coastal areas from Onslow to Exmouth has been cancelled.


At 11:00 am WST Severe Tropical Cyclone Narelle, Category 3 was estimated to be
335 kilometres west of Exmouth and
460 kilometres northwest of Carnarvon and
moving south southwest at 15 kilometres per hour.

Severe Tropical Cyclone Narelle is expected to continue to move toward the
south southwest.

If the cyclone moves on a track which brings it closer to the coast then a
period of gales with gusts to 100 kilometres per hour may develop in coastal
areas between Exmouth and Cape Cuvier during Sunday and may extend south to
Carnarvon and Denham late Sunday or early Monday.

Tides along the west Pilbara coast and down the west coast are likely to rise
above the normal high tide mark with flooding of low lying coastal areas
possible.

DFES-State Emergency Service advises of the following community alerts:

BLUE ALERT: Coastal communities from Exmouth to Coral Bay should be taking
precautions.
Communities between Coral Bay and Denham should listen for the next advice.

Details of Severe Tropical Cyclone Narelle at 11:00 am WST:
.Centre located near...... 21.6 degrees South 110.9 degrees East
.Location accuracy........ within 35 kilometres
.Recent movement.......... towards the south southwest at 15 kilometres per hour
.Wind gusts near centre... 195 kilometres per hour
.Severity category........ 3
.Central pressure......... 960 hectoPascals

The next advice will be issued by 3:00 pm WST Sunday 13 January.

Cyclone advices and State Emergency Service Community Alerts are available by
dialling 1300 659 210
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Re: Tropical Cyclone Narelle

Postby von-Kármán » Sun Jan 13, 2013 1:17 pm

Latest JTWC has her weakening very very rapidly, which is not surprising given shell be ripped up by 50-90kt shear!
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Re: Tropical Cyclone Narelle (Technical Discussion Only)

Postby brayden » Sun Jan 13, 2013 2:45 pm

PRIORITY

TROPICAL CYCLONE ADVICE NUMBER 30
Issued at 2:32 pm WST on Sunday 13 January 2013


The Cyclone WARNING for coastal areas from Exmouth to Denham has been CANCELLED.

At 2:00 pm WST Severe Tropical Cyclone Narelle, Category 3 was estimated to be
355 kilometres west of Exmouth and
440 kilometres northwest of Carnarvon and
moving south southwest at 14 kilometres per hour.

Severe Tropical Cyclone Narelle is expected to continue to move toward the
south southwest and is not expected to come closer to the coast before
weakening. Narelle is not expected to produce gales on the coast, however a
Severe Thunderstorm Warning has been issued for Sunday afternoon and evening
for parts of the Gascoyne and Central West forecast districts including coastal
areas between Cape Cuvier and Northhampton.

Tides along the west Pilbara coast and down the west coast are likely to rise
above the normal high tide mark with flooding of low lying coastal areas
possible.

DFES-State Emergency Service advises of the following community alerts:

ALL CLEAR: People in coastal communities from Exmouth to Coral Bay are advised
that the risk of gales has passed.


Details of Severe Tropical Cyclone Narelle at 2:00 pm WST:
.Centre located near...... 22.0 degrees South 110.7 degrees East
.Location accuracy........ within 55 kilometres
.Recent movement.......... towards the south southwest at 14 kilometres per hour
.Wind gusts near centre... 165 kilometres per hour
.Severity category........ 3
.Central pressure......... 968 hectoPascals

No further advices will be issued for this system unless it moves back towards
the coast.

Cyclone advices and State Emergency Service Community Alerts are available by
dialling 1300 659 210
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Re: Tropical Cyclone Narelle

Postby Cyclone Alby » Sun Jan 13, 2013 7:20 pm

Sat image now is showing a eye clearly in the middle ?

I thought the eye had collapsed after experincing dry air and higher wind shear plus going into cooler sst's
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2012 YTD 716.6 mm
2013 YTD 1174.6 mm :)
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Re: Tropical Cyclone Narelle

Postby Fu Manchu » Sun Jan 13, 2013 7:32 pm

It sure is clearly visible.
It may be there but won't be for too much longer as she i going to really weaken fast. The shear, cooler sst's and an injection (of sorts) of dry air was like a kick in the nuts that drops you. Then you get up again.

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Re: Tropical Cyclone Narelle

Postby Cyclone Alby » Sun Jan 13, 2013 9:06 pm

Bom's latest update still got her at cat 3, by wednesday a tropical low near the south west coast
Margaret River

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2013 YTD 1174.6 mm :)
2014 YTD 840.2mm
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Re: Tropical Cyclone Narelle

Postby Figgles61 » Mon Jan 14, 2013 9:58 pm

Email this evening from FSC advising boat owners to be prepared for Narelle:



CLUB BULLETIN 14 January 2013


To all Fremantle Sailing Club Members

Following the passage of Tropical Cyclone 'Narelle' the Bureau of Meteorology has issued a Strong wind warning for Tuesday for the Perth Coast, cyclones do not always follow the predicted path, and it would be prudent to prepare for a strong blow.

I request that members please come down and check mooring lines, weights and equipment on vessels as soon as possible. Also double-check that halyards are secure.

Your assistance is greatly appreciated.

Trenton Eaves
FSC HARBOUR MASTER




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Tropical Cyclone Narelle

Postby Fu Manchu » Tue Jan 15, 2013 6:16 am

Looks as good as dead on IR loop.
Most cloud ripped from her now making its way over the SW.

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