NW Australia: BILLY - Tropical Cyclone: Discussion

[Chacor]

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 23
Issued at 9:50 pm WDT on Saturday, 20 December 2008
BY THE BUREAU OF METEOROLOGY
TROPICAL CYCLONE WARNING CENTRE PERTH

A Cyclone WARNING is current for coastal and island communities from Kalumburu
to Cockatoo Island.

A Cyclone WATCH is current for coastal areas from Cockatoo Island to Broome.

At 9:00 pm WDT Ex-Tropical Cyclone Billy was estimated to be
105 kilometres south southeast of Kalumburu and
135 kilometres west northwest of Wyndham and
moving west southwest at 7 kilometres per hour.

Ex Tropical Cyclone Billy is moving across the Kimberley and is expected to move
off the coast later on Sunday or Monday then redevelop into a tropical cyclone.
Gales may develop between Kalumburu and Cockatoo Island overnight Sunday or
during Monday and may extend to Broome late on Monday or Tuesday.

Widespread heavy rainfall is likely over northern parts of the Kimberley over
the next few days. Significant stream rises and local flooding are expected in
these areas tonight and on Sunday.

Details of Ex-Tropical Cyclone Billy at 9:00 pm WDT:
.Centre located near...... 15.2 degrees South 126.9 degrees East
.Location accuracy........ within 46 kilometres
.Recent movement.......... towards the west southwest at 7 kilometres per hour
.Wind gusts near centre... 85 kilometres per hour
.Severity category........ below cyclone intensity
.Central pressure......... 998 hectoPascals

ALL CLEAR WITH CAUTION: People in communities at WYNDHAM, OOMBULGURRI, KALUMBURU
and MITCHELL PLATEAU and surrounding communities are advised to proceed with
caution.
The next advice will be issued by 1:00 am WDT Sunday 21 December.
Cyclone advices and State Emergency Service Community Alerts are available by
dialling 1300 659 210


A map showing the track of the cyclone is available at:
http://www.bom.gov.au/weather/cyclone

[Chacor]

Expected to reintensify even stronger than it was... 65kt 10-min forecast in 72h.

AXAU01 APRF 201255
IDW27600
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by PERTH TROPICAL CYCLONE WARNING CENTRE
at: 1255 UTC 20/12/2008
Name: Billy
Data At: 1200 UTC
Latitude: 15.2S
Longitude: 126.9E
Location Accuracy: within 25 nm [46 km]
Movement Towards: west southwest [255 deg]
Speed of Movement: 4 knots [7 km/h]
Maximum 10-Minute Wind: 30 knots [55 km/h]
Maximum 3-Second Wind Gust: 45 knots [85 km/h]
Central Pressure: 998 hPa
Radius of 34-knot winds NE quadrant:
Radius of 34-knot winds SE quadrant:
Radius of 34-knot winds SW quadrant:
Radius of 34-knot winds NW quadrant:
Radius of 48-knot winds NE quadrant:
Radius of 48-knot winds SE quadrant:
Radius of 48-knot winds SW quadrant:
Radius of 48-knot winds NW quadrant:
Radius of 64-knot winds:
Radius of Maximum Winds: 20 nm [37 km]
Dvorak Intensity Code: T2.5/2.5/W1.0/24HRS
Pressure of outermost isobar: 1000 hPa
Radius of outermost closed isobar: 70 nm [130 km]
Storm Depth: Deep
FORECAST DATA
Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure
[UTC] : degrees : nm [km]: knots[km/h]: hPa
+12: 21/0000: 15.4S 126.0E: 055 [100]: 030 [055]: 998
+24: 21/1200: 15.4S 125.2E: 085 [155]: 030 [055]: 998
+36: 22/0000: 15.5S 124.2E: 095 [175]: 035 [065]: 992
+48: 22/1200: 15.8S 123.0E: 110 [205]: 050 [095]: 984
+60: 23/0000: 16.1S 121.6E: 150 [280]: 060 [110]: 976
+72: 23/1200: 17.0S 120.7E: 240 [445]: 065 [120]: 972
REMARKS:
EX TC Billy continues to track slowly to the WSW over land. Dvorak CB 0.5 wrap
gives a DT 2.5, which agrees with the MET. Consensus track has the system
continuing to move WSW, and it is expected to be over water around 210000UTC,
where the system should re-develop into a tropical cyclone. In the longer term
the system should intensify with favourable wind shear conditions and warm SSTs.
==
The next bulletin for this system will be issued by: 20/1900 UTC by Perth TCWC.

[Sanibel]

We'll see if the re-emergence, redevelopment prediction holds true.

[wyq614]

I believe it will redevelop, but not that strong... My guess 10-min 55kts

[Crostorm]

IDW27600
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by PERTH TROPICAL CYCLONE WARNING CENTRE
at: 1842 UTC 20/12/2008
Name: Billy
Data At: 1800 UTC
Latitude: 15.3S
Longitude: 126.3E
Location Accuracy: within 25 nm [46 km]
Movement Towards: west southwest [258 deg]
Speed of Movement: 5 knots [9 km/h]
Maximum 10-Minute Wind: 30 knots [55 km/h]
Maximum 3-Second Wind Gust: 45 knots [85 km/h]
Central Pressure: 998 hPa
Radius of 34-knot winds NE quadrant:
Radius of 34-knot winds SE quadrant:
Radius of 34-knot winds SW quadrant:
Radius of 34-knot winds NW quadrant:
Radius of 48-knot winds NE quadrant:
Radius of 48-knot winds SE quadrant:
Radius of 48-knot winds SW quadrant:
Radius of 48-knot winds NW quadrant:
Radius of 64-knot winds:
Radius of Maximum Winds: 20 nm [37 km]
Dvorak Intensity Code: T2.5/2.5/W1.0/24HRS
Pressure of outermost isobar: 1002 hPa
Radius of outermost closed isobar: 70 nm [130 km]
Storm Depth: Deep
FORECAST DATA
Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure
[UTC] : degrees : nm [km]: knots[km/h]: hPa
+12: 21/0600: 15.3S 125.4E: 055 [100]: 030 [055]: 998
+24: 21/1800: 15.4S 124.6E: 085 [155]: 030 [055]: 996
+36: 22/0600: 15.7S 123.5E: 095 [175]: 040 [075]: 990
+48: 22/1800: 16.1S 122.3E: 110 [205]: 050 [095]: 984
+60: 23/0600: 16.8S 121.3E: 150 [280]: 060 [110]: 976
+72: 23/1800: 17.7S 120.2E: 240 [445]: 065 [120]: 972
REMARKS:
EX TC Billy continues to track slowly to the WSW over land. The system has
weakened over the last 24 hours, MET is 2.5 and the FT 2.5. Consensus track has
the system continuing to move WSW, and it is expected to be over water around
210000UTC, where the system should re-develop into a tropical cyclone. In the
longer term the system should intensify with favourable wind shear conditions
and warm SSTs.
==
The next bulletin for this system will be issued by: 21/0100 UTC by Perth TCWC.

[Chacor]

70 kts now forecast.

AXAU01 APRF 210055
IDW27600
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by PERTH TROPICAL CYCLONE WARNING CENTRE
at: 0055 UTC 21/12/2008
Name: Billy
Data At: 0000 UTC
Latitude: 15.3S
Longitude: 125.9E
Location Accuracy: within 25 nm [46 km]
Movement Towards: west [264 deg]
Speed of Movement: 5 knots [9 km/h]
Maximum 10-Minute Wind: 25 knots [45 km/h]
Maximum 3-Second Wind Gust: 45 knots [85 km/h]
Central Pressure: 997 hPa
Radius of 34-knot winds NE quadrant:
Radius of 34-knot winds SE quadrant:
Radius of 34-knot winds SW quadrant:
Radius of 34-knot winds NW quadrant:
Radius of 48-knot winds NE quadrant:
Radius of 48-knot winds SE quadrant:
Radius of 48-knot winds SW quadrant:
Radius of 48-knot winds NW quadrant:
Radius of 64-knot winds:
Radius of Maximum Winds:
Dvorak Intensity Code: T2.0/2.0/W1.0/24HRS
Pressure of outermost isobar: 1000 hPa
Radius of outermost closed isobar: 60 nm [110 km]
Storm Depth: Deep
FORECAST DATA
Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure
[UTC] : degrees : nm [km]: knots[km/h]: hPa
+12: 21/1200: 15.3S 125.2E: 055 [100]: 025 [045]: 997
+24: 22/0000: 15.3S 124.3E: 085 [155]: 030 [055]: 994
+36: 22/1200: 15.6S 123.3E: 120 [220]: 045 [085]: 986
+48: 23/0000: 16.0S 121.9E: 150 [280]: 050 [095]: 983
+60: 23/1200: 16.7S 120.7E: 200 [365]: 060 [110]: 976
+72: 24/0000: 17.6S 118.9E: 245 [455]: 070 [130]: 970
REMARKS:
EX TC Billy continues to track steadily to the west over the north Kimberley.
The system has retained excellent structure over land. It is expected to remain
in a low shear environment and should redevelop quickly on Monday as it moves
offshore into an area of favourable SSTs.

NWP is now analysing a stronger mid level ridge to the south, which is confirmed
by the observations and the models maintain the strength of the ridge through
the next four days, keeping the system on a more westerly track. However the
possibility of a coastal landfall is still significant.

The UK vortex tracker output for the 201200UTC run appears significantly
different to the track obtained by subjectively assessing the vorticity and wind
fields.

==
The next bulletin for this system will be issued by: 21/0700 UTC by Perth TCWC.

[Chacor]

Reissued with further comments...

AXAU01 APRF 210237
IDW27600
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by PERTH TROPICAL CYCLONE WARNING CENTRE
at: 0236 UTC 21/12/2008
Name: Billy
Data At: 0000 UTC
Latitude: 15.3S
Longitude: 125.9E
Location Accuracy: within 25 nm [46 km]
Movement Towards: west [264 deg]
Speed of Movement: 5 knots [9 km/h]
Maximum 10-Minute Wind: 25 knots [45 km/h]
Maximum 3-Second Wind Gust: 45 knots [85 km/h]
Central Pressure: 997 hPa
Radius of 34-knot winds NE quadrant:
Radius of 34-knot winds SE quadrant:
Radius of 34-knot winds SW quadrant:
Radius of 34-knot winds NW quadrant:
Radius of 48-knot winds NE quadrant:
Radius of 48-knot winds SE quadrant:
Radius of 48-knot winds SW quadrant:
Radius of 48-knot winds NW quadrant:
Radius of 64-knot winds:
Radius of Maximum Winds:
Dvorak Intensity Code: T2.0/2.0/W1.0/24HRS
Pressure of outermost isobar: 1000 hPa
Radius of outermost closed isobar: 60 nm [110 km]
Storm Depth: Deep
FORECAST DATA
Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure
[UTC] : degrees : nm [km]: knots[km/h]: hPa
+12: 21/1200: 15.3S 125.2E: 055 [100]: 025 [045]: 997
+24: 22/0000: 15.3S 124.3E: 085 [155]: 030 [055]: 994
+36: 22/1200: 15.6S 123.3E: 120 [220]: 045 [085]: 986
+48: 23/0000: 16.0S 121.9E: 150 [280]: 050 [095]: 983
+60: 23/1200: 16.7S 120.7E: 200 [365]: 060 [110]: 976
+72: 24/0000: 17.6S 118.9E: 245 [455]: 070 [130]: 970
REMARKS:
Ex-TC Billy continues to track steadily to the west over the north Kimberley.
The system has retained excellent structure over land. It is expected to remain
in a low shear environment and should redevelop quickly on Monday as it moves
offshore into an area of favourable SSTs. Shear and ocean heat conditions are
expected to remain favourable for at least the next three days.

The mid-level ridge to the south of ex-Billy is stronger than was previously
forecast by NWP and the models maintain the strength of the ridge through the
next four days. Of equal or greater significance to the future motion of the
system will be the development and movement of the low currently in the Gulf of
Carpentaria. This system is expected to track steadily west over the base of the
Top End of the Northern Territory and reach the NT/WA border on Tuesday night.
NWP now portrays this sytem as having enough strength to erode the peripheral
ridge to the east of 03U/05S and this is likely the primary reason for the
change in model forecast motion from southwest to westwards on Wednesday and
Thursday.

If this trailing system is not strong enough to erode the preipheral ridge then
a southwest track towards the coast is likely, and so the possibility of a
coastal landfall is still significant.



==
The next bulletin for this system will be issued by: 21/0700 UTC by Perth TCWC.

[HURAKAN]

[HURAKAN]

Australian Government Bureau of Meteorology
Western Australia

TROPICAL CYCLONE OUTLOOK FOR NORTHWESTERN AUSTRALIA
Issued at 2:00pm WDT on Saturday the 20th of December 2008
For the area south of LATITUDE 10 SOUTH between LONGITUDES 110 - 125 EAST

A cyclone advice is current for Tropical Cyclone Billy, located over the north
Kimberley, outside the region. TC Billy is expected to weaken as it continues to
move west over land in the short term. It is expected to move off the northwest
Kimberley coast into the region on Sunday or Monday and then redevelop into a
tropical cyclone. Please refer to the latest cyclone advice.

Full details available from Bureau of Meteorology
Ph 1300 659 210 or visit http://www.bom.gov.au

There are no other significant tropical lows evident and the likelihood of a
tropical cyclone occurring in the region in the next three days is:
Sunday : Moderate
Monday : High
Tuesday : High

** NOTE: Development potential is an estimate of the probability of **
** tropical cyclone development within a 24 hour period. **
** LOW = 10% or less MODERATE = 20-40% HIGH = 50% or more **

[Chacor]

Look at the date. That is over 24 hours old.

[HURAKAN]

Australian Government Bureau of Meteorology
Western Australia

TROPICAL CYCLONE OUTLOOK FOR NORTHWESTERN AUSTRALIA
Issued at 2:30pm WDT on Sunday the 21st of December 2008
For the area south of LATITUDE 10 SOUTH between LONGITUDES 110 - 125 EAST

A cyclone advice is current for Ex Tropical Cyclone Billy, located over the
northwest Kimberley, outside the region. Ex TC Billy is moving slowly westwards
and is expected to move off the northwest Kimberley coast into the region on
Monday and then redevelop into a tropical cyclone. Please refer to the latest
cyclone advice.

Full details available from Bureau of Meteorology
Ph 1300 659 210 or visit http://www.bom.gov.au

There are no other significant tropical lows evident and the likelihood of a
tropical cyclone occurring in the region in the next three days is:
Monday : High
Tuesday : High
Wednesday : High

** NOTE: Development potential is an estimate of the probability of **
** tropical cyclone development within a 24 hour period. **
** LOW = 10% or less MODERATE = 20-40% HIGH = 50% or more **

[HURAKAN]

[P.K.]

Winds are back up to 30kts even though it is still over land.

TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by PERTH TROPICAL CYCLONE WARNING CENTRE
at: 1907 UTC 21/12/2008
Name: Billy
Data At: 1800 UTC
Latitude: 15.7S
Longitude: 124.7E
Location Accuracy: within 30 nm [55 km]
Movement Towards: west southwest [243 deg]
Speed of Movement: 4 knots [8 km/h]
Maximum 10-Minute Wind: 30 knots [55 km/h]
Maximum 3-Second Wind Gust: 45 knots [85 km/h]
Central Pressure: 992 hPa
Radius of 34-knot winds NE quadrant:
Radius of 34-knot winds SE quadrant:
Radius of 34-knot winds SW quadrant:
Radius of 34-knot winds NW quadrant:
Radius of 48-knot winds NE quadrant:
Radius of 48-knot winds SE quadrant:
Radius of 48-knot winds SW quadrant:
Radius of 48-knot winds NW quadrant:
Radius of 64-knot winds:
Radius of Maximum Winds:
Dvorak Intensity Code: NA
Pressure of outermost isobar: 1002 hPa
Radius of outermost closed isobar: 90 nm [165 km]
Storm Depth: Deep
FORECAST DATA
Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure
[UTC] : degrees : nm [km]: knots[km/h]: hPa
+12: 22/0600: 16.1S 123.6E: 060 [110]: 040 [075]: 990
+24: 22/1800: 16.4S 122.7E: 090 [165]: 050 [095]: 985
+36: 23/0600: 16.9S 121.6E: 120 [225]: 060 [110]: 978
+48: 23/1800: 17.2S 120.6E: 155 [285]: 065 [120]: 974
+60: 24/0600: 17.4S 119.3E: 200 [375]: 075 [140]: 966
+72: 24/1800: 17.6S 118.0E: 250 [465]: 080 [150]: 962
REMARKS:
Latest IR imagery shows Ex-TC Billy moving WSW near the northwest Kimberley
coast.
The system is expected to cross the coast between Cockatoo Island and Kuri Bay.


Latest imagery shows good convection over the ocean to the north and west.
Aside from being over land the environment remains favourable. This suggests
that once the system moves offshore the re-intensification into a tropical
cyclone
should be rapid. However, the proximity to the land may inhibit the expected
re-intensification.

The WSW motion is expected to continued with a mid-level ridge to the south.
In the longer term a low currently in the Gulf of Carpentaria may have enough
strength to erode this peripheral ridge.


==
The next bulletin for this system will be issued by: 22/0100 UTC by Perth TCWC.

[HURAKAN]

TROPICAL CYCLONE ADVICE NUMBER 34
Issued at 7:00 am WDT on Monday, 22 December 2008
BY THE BUREAU OF METEOROLOGY
TROPICAL CYCLONE WARNING CENTRE PERTH

A Cyclone WARNING is current for coastal and island communities from Mitchell
Plateau to Broome.
A Cyclone WATCH is current for coastal areas from Broome to Port Hedland.

At 6:00 am WDT Ex-Tropical Cyclone Billy was estimated to be
26 kilometres west southwest of Kuri Bay and
345 kilometres northeast of Broome and
moving west southwest at 9 kilometres per hour.

Ex-TC Billy is now moving west southwest off the Kimberley coast near Kuri Bay.
It is expected to redevelop into a tropical cyclone this morning and GALES are
expected to develop between Mitchell Plateau and Cape Leveque during today.
DESTRUCTIVE wind gusts to 130 kilometres per hour are possible about the far
northern part of the Dampier Peninsula near Cape Leveque for a period tonight.
GALES may extend down the coast to Broome overnight, and then to Port Hedland
later on Tuesday as Billy moves further to the west.

Widespread heavy rainfall over the northern Kimberley, with significant stream
rises and local flooding, is likely to contract to the west Kimberley coast
today.


Details of Ex-Tropical Cyclone Billy at 6:00 am WDT:
.Centre located near...... 15.6 degrees South 124.3 degrees East
.Location accuracy........ within 55 kilometres
.Recent movement.......... towards the west southwest at 9 kilometres per hour
.Wind gusts near centre... 85 kilometres per hour
.Severity category........ below cyclone intensity
.Central pressure......... 992 hectoPascals

FESA-State Emergency Service advises that there are no community alerts at
present. People in communities between Mitchell Plateau and Port Hedland should
listen for the next advice.
The next advice will be issued by 10:00 am WDT Monday 22 December.Cyclone
advices and State Emergency Service Community Alerts are available by
dialling 1300 659 210

A map showing the track of the cyclone is available at:
http://www.bom.gov.au/weather/cyclone

[HURAKAN]

[Ed Mahmoud]

Looks like at least a depression to me, in my amateur and unofficial opinion. Sweet looking polar outflow.

[Chacor]

Billy is now a TC again. Forecast to reach 85 kt 10-min.

TROPICAL CYCLONE ADVICE NUMBER 35
Issued at 9:55 am WDT on Monday, 22 December 2008
BY THE BUREAU OF METEOROLOGY
TROPICAL CYCLONE WARNING CENTRE PERTH

A Cyclone WARNING is current for coastal and island communities from Mitchell
Plateau to Bidyadanga.
A Cyclone WATCH is current for coastal areas from Bidyadanga to Port Hedland.

At 9:00 am WDT Tropical Cyclone Billy was estimated to be
26 kilometres west southwest of Kuri Bay and
345 kilometres northeast of Broome and
moving west at 8 kilometres per hour.

TC Billy has re-formed near the northwest Kimberley coast and is moving west
southwest off the Kimberley coast near Kuri Bay. GALES are expected to develop
between Mitchell Plateau and Cape Leveque today. DESTRUCTIVE wind gusts to 130
kilometres per hour are possible about the far northern part of the Dampier
Peninsula near Cape Leveque for a period overnight. GALES may extend down the
coast to Broome early on Tuesday.

Widespread heavy rainfall is expected over the north and northwest Kimberley,
with significant stream rises and local flooding. Rainfall should ease over the
north and east Kimberley over the next 24 hours as the cyclone moves away.


Details of Tropical Cyclone Billy at 9:00 am WDT:
.Centre located near...... 15.6 degrees South 124.3 degrees East
.Location accuracy........ within 55 kilometres
.Recent movement.......... towards the west at 8 kilometres per hour
.Wind gusts near centre... 95 kilometres per hour
.Severity category........ 1
.Central pressure......... 992 hectoPascals

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

BLUE ALERT: People in or near the communities between Mitchell Plateau and
Bidyadanga, including Mitchell Plateau, Kuri Bay, One Arm Point, Cape Leveque,
Cockatoo Island, Koolan Island, Djarindjin, Lombadina, Beagle Bay, Broome and
Bidyadanga should start taking precautions. The community of Derby is NOT
included.

People in communities between Bidyadanga and Port Hedland should listen for the
next advice.
The next advice will be issued by 1:00 pm WDT Monday 22 December.
Cyclone advices and State Emergency Service Community Alerts are available by
dialling 1300 659 210


A map showing the track of the cyclone is available at:
http://www.bom.gov.au/weather/cyclone


From the technical bulletin:
FORECAST DATA
Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure
[UTC] : degrees : nm [km]: knots[km/h]: hPa
+12: 22/1200: 15.8S 123.4E: 060 [110]: 050 [095]: 983
+24: 23/0000: 16.1S 122.4E: 090 [165]: 060 [110]: 976
+36: 23/1200: 16.7S 121.6E: 120 [225]: 065 [120]: 972
+48: 24/0000: 16.9S 120.4E: 155 [285]: 075 [140]: 964
+60: 24/1200: 17.2S 119.4E: 200 [375]: 080 [150]: 960
+72: 25/0000: 17.3S 118.1E: 250 [465]: 085 [155]: 956

[HURAKAN]

WTXS32 PGTW 220300
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 05S (BILLY) WARNING NR 008//
RMKS/
1. TROPICAL CYCLONE 05S (BILLY) WARNING NR 008
01 ACTIVE TROPICAL CYCLONES IN SOUTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
---
WARNING POSITION:
220000Z --- NEAR 15.5S 124.3E
MOVEMENT PAST SIX HOURS - 280 DEGREES AT 05 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 055 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
REPEAT POSIT: 15.5S 124.3E
---
FORECASTS:
12 HRS, VALID AT:
221200Z --- 15.8S 123.0E
MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT
060 NM SOUTHEAST QUADRANT
060 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 250 DEG/ 06 KTS
---
24 HRS, VALID AT:
230000Z --- 16.2S 121.8E
MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
070 NM SOUTHEAST QUADRANT
070 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 250 DEG/ 06 KTS
---
36 HRS, VALID AT:
231200Z --- 16.6S 120.6E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT
075 NM SOUTHEAST QUADRANT
075 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 255 DEG/ 06 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
240000Z --- 16.9S 119.4E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
030 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT
075 NM SOUTHEAST QUADRANT
075 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
VECTOR TO 72 HR POSIT: 260 DEG/ 05 KTS
---
72 HRS, VALID AT:
250000Z --- 17.3S 117.4E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 035 NM NORTHEAST QUADRANT
035 NM SOUTHEAST QUADRANT
035 NM SOUTHWEST QUADRANT
035 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT
085 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
080 NM NORTHWEST QUADRANT
---
REMARKS:
220300Z POSITION NEAR 15.6S 124.0E.
TROPICAL CYCLONE (TC) 05S (BILLY) LOCATED APPROXIMATELY 700 NM EAST-
NORTHEAST OF LEARMONTH, AUSTRALIA, HAS TRACKED WESTWARD AT 05 KNOTS
OVER THE PAST SIX HOURS. TC 05S HAS CROSSED THE KIMBERLY COAST INTO
THE INDIAN OCEAN NEAR KURI BAY. TC 05S CONTINUES TO TRACK GENERALLY
WESTWARD ON THE EQUATORWARD PERIPHERY OF THE MID-LEVEL STEERING
RIDGE TO THE SOUTHEAST OVER CENTRAL AUSTRALIA, WHICH WILL CONTINUE
TO GENERATE A WESTWARD TRACK THROUGHOUT THE FORECAST PERIOD.
TROUGHING TO THE SOUTHWEST OF AUSTRALIA IS EXPECTED TO CAUSE THE
WESTERN EXTENSION OF THE STEERING RIDGE TO RETREAT EASTWARD NEAR TAU
24, RESULTING IN A MORE WEST-SOUTHWESTWARD TRACK. INTENSIFICATION IS
EXPECTED TO BE SLOW, DUE TO INTERACTION WITH LAND IN THE THE NEAR
TERM, AND INHIBITION DUE TO THE DEVELOPING SYSTEM IN THE GULF OF
CARPENTARIA. AFTER TAU 48, INTENSIFICATION WILL CONTINUE TO BE SLOW
DUE TO INCREASING VERTICAL WINDSHEAR AND DECREASING SEA SURFACE
TEMPERATURES. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 220000Z IS 12 FEET.
NEXT WARNINGS AT 221500Z AND 230300Z.

[Chacor]

AXAU01 APRF 220640
IDW27600
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by PERTH TROPICAL CYCLONE WARNING CENTRE
at: 0640 UTC 22/12/2008
Name: Billy
Data At: 0600 UTC
Latitude: 15.6S
Longitude: 124.1E
Location Accuracy: within 30 nm [55 km]
Movement Towards: west [270 deg]
Speed of Movement: 3 knots [5 km/h]
Maximum 10-Minute Wind: 35 knots [65 km/h]
Maximum 3-Second Wind Gust: 50 knots [95 km/h]
Central Pressure: 991 hPa
Radius of 34-knot winds NE quadrant: 70 nm [130 km]
Radius of 34-knot winds SE quadrant: 30 nm [55 km]
Radius of 34-knot winds SW quadrant: 50 nm [95 km]
Radius of 34-knot winds NW quadrant: 70 nm [130 km]
Radius of 48-knot winds NE quadrant:
Radius of 48-knot winds SE quadrant:
Radius of 48-knot winds SW quadrant:
Radius of 48-knot winds NW quadrant:
Radius of 64-knot winds:
Radius of Maximum Winds:
Dvorak Intensity Code: NA
Pressure of outermost isobar: 1000 hPa
Radius of outermost closed isobar: 80 nm [150 km]
Storm Depth: Deep
FORECAST DATA
Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure
[UTC] : degrees : nm [km]: knots[km/h]: hPa
+12: 22/1800: 15.8S 123.0E: 060 [110]: 050 [095]: 983
+24: 23/0600: 16.4S 122.0E: 090 [165]: 055 [100]: 980
+36: 23/1800: 16.8S 120.9E: 125 [230]: 065 [120]: 972
+48: 24/0600: 17.0S 119.6E: 155 [285]: 075 [140]: 964
+60: 24/1800: 16.9S 118.2E: 205 [375]: 075 [140]: 965
+72: 25/0600: 16.8S 117.0E: 250 [465]: 075 [140]: 964
REMARKS:
Satellite imagery over the last 6 hours has shown a decrease in curvature and
coldness of the cloud top temperatures. DT/CI is assigned 3.0.

The system has slowed over the last 6 hours and remains in close proximity to
land. The model guidance indicates the cyclone should remain north of the
mid-level ridge and be steered in a generally westerly direction. In the 24 to
48 hour time frame the system should intensify as it moves away from the coast.


==
The next bulletin for this system will be issued by: 22/1300 UTC by Perth TCWC.

[Chacor]

AXAU01 APRF 221258
IDW27600
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by PERTH TROPICAL CYCLONE WARNING CENTRE
at: 1257 UTC 22/12/2008
Name: Billy
Data At: 1200 UTC
Latitude: 16.1S
Longitude: 123.5E
Location Accuracy: within 30 nm [55 km]
Movement Towards: west southwest [245 deg]
Speed of Movement: 6 knots [11 km/h]
Maximum 10-Minute Wind: 40 knots [75 km/h]
Maximum 3-Second Wind Gust: 55 knots [100 km/h]
Central Pressure: 989 hPa
Radius of 34-knot winds NE quadrant: 60 nm [110 km]
Radius of 34-knot winds SE quadrant: 30 nm [55 km]
Radius of 34-knot winds SW quadrant: 35 nm [65 km]
Radius of 34-knot winds NW quadrant: 60 nm [110 km]
Radius of 48-knot winds NE quadrant:
Radius of 48-knot winds SE quadrant:
Radius of 48-knot winds SW quadrant:
Radius of 48-knot winds NW quadrant:
Radius of 64-knot winds:
Radius of Maximum Winds: 20 nm [37 km]
Dvorak Intensity Code: T3.0/3.0/S0.0/12HRS
Pressure of outermost isobar: 1000 hPa
Radius of outermost closed isobar: 90 nm [165 km]
Storm Depth: Deep
FORECAST DATA
Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure
[UTC] : degrees : nm [km]: knots[km/h]: hPa
+12: 23/0000: 16.5S 122.3E: 060 [110]: 050 [095]: 983
+24: 23/1200: 17.3S 121.2E: 090 [165]: 055 [100]: 980
+36: 24/0000: 17.4S 120.2E: 120 [225]: 070 [130]: 968
+48: 24/1200: 17.5S 118.9E: 155 [285]: 080 [150]: 960
+60: 25/0000: 17.2S 117.3E: 200 [375]: 075 [140]: 965
+72: 25/1200: 17.1S 116.2E: 250 [465]: 070 [130]: 968
REMARKS:
A curved band wrap of around 0.7 was obtained on the 0930 VIS image, however it
is difficult to apply curved band pattern on most recent images. The system is
showing some improvement in the last six hours but remains close to the coast
which may be hindering development at this stage.

Although bulk shear is forecast to remain low to moderate over the next 48-72
hours the system has a very small core and is likely to be very responsive to
changes in the environment including relatively moderate amounts of shear.
Oceanic heat content remains favourable over the forecast track for the next 72
hours. Intensifcation is expected as the system moves away from the coast.

In the 24-72 hour time frame, continued west to west-southwest movement is
partially dependent on the erosion of the peripheral ridge by the system
currently in the Gulf of Carpentaria, hence the risk of coastal impact is still
considered significant.

==
The next bulletin for this system will be issued by: 22/1900 UTC by Perth TCWC.