SIO: ILSA - ex-Tropical Cyclone (22S)

[HURAKAN]

Eye coming back.

[HURAKAN]

HIGH SEAS WEATHER WARNING FOR METAREA 10 ISSUED BY THE
AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE PERTH
AT 0641UTC 20 MARCH 2009

HURRICANE FORCE WIND WARNING

Please be aware, wind gusts can be a further 40 percent stronger than the
averages given here, and maximum waves may be up to twice the height.

SITUATION
At 0600 UTC Severe Tropical Cyclone Ilsa was centred within 20 nautical miles of
latitude sixteen decimal two south (16.2S)
longitude one hundred and four decimal two east (104.2E)
Recent movement : west at 8 knots
Maximum winds : 80 knots
Central pressure: 967 hPa

AREA AFFECTED
Within 60 nautical miles in NE quadrant
and within 90 nautical miles in SE quadrant
and within 90 nautical miles in SW quadrant
and within 60 nautical miles in NW quadrant.

FORECAST
Maximum winds to 80 knots near the centre easing to 65 knots by 0600 UTC 21
March.
Winds above 64 knots within 25 nautical miles of centre with high to phenomenal
seas and heavy swell.
Winds above 48 knots within 40 nautical miles of centre with very rough to high
seas and moderate to heavy swell.
Winds above 34 knots within 60 nautical miles of the centre in northern
quadrants extending to within 90 nautical miles in southern quadrants, with
rough seas and moderate swell
Forecast positions
At 1800 UTC 20 March: Within 50 nautical miles of 16.3 south 102.7 east
Central pressure 971 hPa.
Winds to 75 knots.
At 0600 UTC 21 March: Within 80 nautical miles of 16.4 south 101.2 east
Central pressure 979 hPa.
Winds to 65 knots.

REMARKS
All ships in the area please send weather reports every three hours.
Regular weather observing ships use normal channels.
Other ships please use either email to tcwcwa@bom.gov.au or fax to +61892632261
or satellite to SAC 1241 through Land Earth Station Perth 312.

Next warning will be issued by 1300 UTC 20 March 2009.

WEATHER PERTH

[HURAKAN]

Very small.

[Chacor]

AXAU01 APRF 201252
IDW27600
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by PERTH TROPICAL CYCLONE WARNING CENTRE
at: 1252 UTC 20/03/2009
Name: Severe Tropical Cyclone Ilsa
Identifier: 18U
Data At: 1200 UTC
Latitude: 15.9S
Longitude: 103.7E
Location Accuracy: within 20 nm [37 km]
Movement Towards: west northwest [282 deg]
Speed of Movement: 7 knots [14 km/h]
Maximum 10-Minute Wind: 80 knots [150 km/h]
Maximum 3-Second Wind Gust: 110 knots [205 km/h]
Central Pressure: 966 hPa
Radius of 34-knot winds NE quadrant: 60 nm [110 km]
Radius of 34-knot winds SE quadrant: 90 nm [165 km]
Radius of 34-knot winds SW quadrant: 90 nm [165 km]
Radius of 34-knot winds NW quadrant: 60 nm [110 km]
Radius of 48-knot winds NE quadrant: 40 nm [75 km]
Radius of 48-knot winds SE quadrant: 40 nm [75 km]
Radius of 48-knot winds SW quadrant: 40 nm [75 km]
Radius of 48-knot winds NW quadrant: 40 nm [75 km]
Radius of 64-knot winds: 25 nm [46 km]
Radius of Maximum Winds: 15 nm [28 km]
Dvorak Intensity Code: T5.0/5.0/W0.5/24HRS
Pressure of outermost isobar: 1006 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: 21/0000: 16.0S 102.3E: 050 [095]: 070 [130]: 975
+24: 21/1200: 16.2S 100.7E: 080 [150]: 060 [110]: 983
+36: 22/0000: 16.5S 99.2E: 110 [210]: 055 [100]: 986
+48: 22/1200: 16.5S 97.2E: 145 [270]: 050 [095]: 990
+60: 23/0000: 16.3S 95.1E: 190 [355]: 045 [085]: 994
+72: 23/1200: 16.3S 92.4E: 240 [445]: 040 [075]: 997
REMARKS:
Time averaged DT of 5.0 based on EIR eye patterns. The 24 hour trend is W- with
the MET and PAT agreeing with the DT.

Recent microwave imagery [TC_SSMIS at 1054UTC] shows weakening of the microwave
eyewall in the southeast quadrant.

Ilsa is expected to weaken gradually under light to moderate shear as oceanic
heat content becomes less favourable. There is strong agreement on a general
westwards track under the influence of the mid-level ridge to the south.

Copyright Commonwealth of Australia
==
The next bulletin for this system will be issued by: 20/1900 UTC by Perth TCWC.

[HURAKAN]

HIGH SEAS WEATHER WARNING FOR METAREA 10 ISSUED BY THE
AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE PERTH
AT 1818UTC 20 MARCH 2009

HURRICANE FORCE WIND WARNING

Please be aware, wind gusts can be a further 40 percent stronger than the
averages given here, and maximum waves may be up to twice the height.

SITUATION
At 1800 UTC Severe Tropical Cyclone Ilsa was centred within 20 nautical miles of
latitude sixteen decimal zero south (16.0S)
longitude one hundred and three decimal zero east (103.0E)
Recent movement : west at 7 knots
Maximum winds : 80 knots
Central pressure: 966 hPa

AREA AFFECTED
Within 60 nautical miles in NE quadrant
and within 90 nautical miles in SE quadrant
and within 90 nautical miles in SW quadrant
and within 60 nautical miles in NW quadrant.

FORECAST
Maximum winds to 80 knots near the centre easing to 55 knots by 1800 UTC 21
March.
Winds above 64 knots within 25 nautical miles of centre until 0600UTC 21 March
with high to phenomenal seas and heavy swell.
Winds above 48 knots within 40 nautical miles of centre with very rough to high
seas and moderate to heavy swell.
Winds above 34 knots within 60 nautical miles of the centre in northern
quadrants extending to within 90 nautical miles in southern quadrants, with
rough seas and moderate swell.
Forecast positions
At 0600 UTC 21 March: Within 50 nautical miles of 16.2 south 101.4 east
Central pressure 979 hPa.
Winds to 65 knots.
At 1800 UTC 21 March: Within 80 nautical miles of 16.4 south 100.0 east
Central pressure 986 hPa.
Winds to 55 knots.

REMARKS
All ships in the area please send weather reports every three hours.
Regular weather observing ships use normal channels.
Other ships please use either email to tcwcwa@bom.gov.au or fax to +61892632261
or satellite to SAC 1241 through Land Earth Station Perth 312.

Next warning will be issued by 0100 UTC 21 March 2009.

WEATHER PERTH

[KWT]

Looks like there is good agreement on a slow weakening trend from here on, the SE portion of the eyewall does seem to be having a bit of a hard time at the moment, looks pretty open right now, probably the result of the shear slowly weakening the system.

[HURAKAN]

TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by PERTH TROPICAL CYCLONE WARNING CENTRE
at: 0053 UTC 21/03/2009
Name: Severe Tropical Cyclone Ilsa
Identifier: 18U
Data At: 0000 UTC
Latitude: 16.0S
Longitude: 102.4E
Location Accuracy: within 20 nm [37 km]
Movement Towards: west [266 deg]
Speed of Movement: 8 knots [14 km/h]
Maximum 10-Minute Wind: 80 knots [150 km/h]
Maximum 3-Second Wind Gust: 110 knots [205 km/h]
Central Pressure: 966 hPa
Radius of 34-knot winds NE quadrant: 60 nm [110 km]
Radius of 34-knot winds SE quadrant: 90 nm [165 km]
Radius of 34-knot winds SW quadrant: 90 nm [165 km]
Radius of 34-knot winds NW quadrant: 60 nm [110 km]
Radius of 48-knot winds NE quadrant: 40 nm [75 km]
Radius of 48-knot winds SE quadrant: 40 nm [75 km]
Radius of 48-knot winds SW quadrant: 40 nm [75 km]
Radius of 48-knot winds NW quadrant: 40 nm [75 km]
Radius of 64-knot winds: 25 nm [46 km]
Radius of Maximum Winds: 15 nm [28 km]
Dvorak Intensity Code: T5.0/5.0/S/12HRS
Pressure of outermost isobar: 1006 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: 21/1200: 16.3S 100.7E: 050 [095]: 070 [130]: 975
+24: 22/0000: 16.7S 98.9E: 080 [150]: 060 [110]: 983
+36: 22/1200: 16.9S 96.9E: 110 [210]: 050 [095]: 990
+48: 23/0000: 17.0S 94.8E: 145 [270]: 045 [085]: 993
+60: 23/1200: 17.4S 92.4E: 190 [355]: 040 [075]: 997
+72: 24/0000: 17.7S 89.9E: 240 [445]: 035 [065]: 999
REMARKS:
Time averaged DT of 5.0 based on EIR EYE and EMBD CENTR patterns. The 24 hour
trend is D- with the MET and PAT agreeing with the DT.

Ilsa consolidated overnight with an eye on EIR apparent most of the time. A
comparison of the SSMIS passes from 1054Z and 2206Z demonstates a slight
improvement in the core convection. This consolidation coincided with a track
across a low gradient of MPI. However decreasing MPI along the forecast track
should see Ilsa gradually weaken over the next 72 hours under light to moderate
shear. There is strong agreement on a general west to west southwest track
during the next 72 hours under the influence of the mid-level ridge to the
south.

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

[HURAKAN]

[HURAKAN]

[HURAKAN]

Pretty small cyclone.

[Chacor]

AXAU01 APRF 210053
IDW27600
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by PERTH TROPICAL CYCLONE WARNING CENTRE
at: 0053 UTC 21/03/2009
Name: Severe Tropical Cyclone Ilsa
Identifier: 18U
Data At: 0000 UTC
Latitude: 16.0S
Longitude: 102.4E
Location Accuracy: within 20 nm [37 km]
Movement Towards: west [266 deg]
Speed of Movement: 8 knots [14 km/h]
Maximum 10-Minute Wind: 80 knots [150 km/h]
Maximum 3-Second Wind Gust: 110 knots [205 km/h]
Central Pressure: 966 hPa
Radius of 34-knot winds NE quadrant: 60 nm [110 km]
Radius of 34-knot winds SE quadrant: 90 nm [165 km]
Radius of 34-knot winds SW quadrant: 90 nm [165 km]
Radius of 34-knot winds NW quadrant: 60 nm [110 km]
Radius of 48-knot winds NE quadrant: 40 nm [75 km]
Radius of 48-knot winds SE quadrant: 40 nm [75 km]
Radius of 48-knot winds SW quadrant: 40 nm [75 km]
Radius of 48-knot winds NW quadrant: 40 nm [75 km]
Radius of 64-knot winds: 25 nm [46 km]
Radius of Maximum Winds: 15 nm [28 km]
Dvorak Intensity Code: T5.0/5.0/S/12HRS
Pressure of outermost isobar: 1006 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: 21/1200: 16.3S 100.7E: 050 [095]: 070 [130]: 975
+24: 22/0000: 16.7S 98.9E: 080 [150]: 060 [110]: 983
+36: 22/1200: 16.9S 96.9E: 110 [210]: 050 [095]: 990
+48: 23/0000: 17.0S 94.8E: 145 [270]: 045 [085]: 993
+60: 23/1200: 17.4S 92.4E: 190 [355]: 040 [075]: 997
+72: 24/0000: 17.7S 89.9E: 240 [445]: 035 [065]: 999
REMARKS:
Time averaged DT of 5.0 based on EIR EYE and EMBD CENTR patterns. The 24 hour
trend is D- with the MET and PAT agreeing with the DT.

Ilsa consolidated overnight with an eye on EIR apparent most of the time. A
comparison of the SSMIS passes from 1054Z and 2206Z demonstates a slight
improvement in the core convection. This consolidation coincided with a track
across a low gradient of MPI. However decreasing MPI along the forecast track
should see Ilsa gradually weaken over the next 72 hours under light to moderate
shear. There is strong agreement on a general west to west southwest track
during the next 72 hours under the influence of the mid-level ridge to the
south.

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

[HURAKAN]

[HURAKAN]

TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by PERTH TROPICAL CYCLONE WARNING CENTRE
at: 0620 UTC 21/03/2009
Name: Severe Tropical Cyclone Ilsa
Identifier: 18U
Data At: 0600 UTC
Latitude: 16.0S
Longitude: 101.5E
Location Accuracy: within 20 nm [37 km]
Movement Towards: west [268 deg]
Speed of Movement: 8 knots [15 km/h]
Maximum 10-Minute Wind: 80 knots [150 km/h]
Maximum 3-Second Wind Gust: 110 knots [205 km/h]
Central Pressure: 967 hPa
Radius of 34-knot winds NE quadrant: 60 nm [110 km]
Radius of 34-knot winds SE quadrant: 90 nm [165 km]
Radius of 34-knot winds SW quadrant: 90 nm [165 km]
Radius of 34-knot winds NW quadrant: 60 nm [110 km]
Radius of 48-knot winds NE quadrant: 40 nm [75 km]
Radius of 48-knot winds SE quadrant: 40 nm [75 km]
Radius of 48-knot winds SW quadrant: 40 nm [75 km]
Radius of 48-knot winds NW quadrant: 40 nm [75 km]
Radius of 64-knot winds: 25 nm [46 km]
Radius of Maximum Winds: 15 nm [28 km]
Dvorak Intensity Code: T4.5/5.0/S0.0/24HRS
Pressure of outermost isobar: 1006 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: 21/1800: 16.4S 99.7E: 050 [095]: 070 [130]: 975
+24: 22/0600: 16.7S 97.8E: 080 [150]: 060 [110]: 983
+36: 22/1800: 16.8S 95.7E: 110 [210]: 055 [100]: 987
+48: 23/0600: 17.0S 93.2E: 145 [270]: 050 [095]: 991
+60: 23/1800: 17.4S 90.9E: 190 [355]: 045 [085]: 993
+72: 24/0600: 18.0S 88.5E: 240 [445]: 040 [075]: 997
REMARKS:
Eye no longer apparent on the EIR or VIS imagery. Time averaged DT of 4.5 based
on EMBD CENTR pattern. The 24 hour trend is W- with the MET 4.0 and PAT 4.5. CI
is held at 5.0.

Decreasing MPI along the forecast track should see Ilsa gradually weaken over
the next 72 hours under light to moderate shear. There is also dry air close to
the system to the west and north. There is strong agreement on a general west to
west southwest track during the next 72 hours under the influence of the
mid-level ridge to the south.

Copyright Commonwealth of Australia
==
The next bulletin for this system will be issued by: 21/1300 UTC by Perth TCWC.

[KWT]

Does look like Ilsa is starting to weaken again as the eye is gone again, though it does have a good deep convection in the center still, will be interesting to see the microwave pass.

[cycloneye]

WTXS32 PGTW 211500
MSGID/GENADMIN/NAVMARFCSTCEN PEARL HARBOR HI/JTWC//
SUBJ/TROPICAL CYCLONE 22S (ILSA) WARNING NR 008//
RMKS/

1. TROPICAL CYCLONE 22S (ILSA) WARNING NR 08
01 ACTIVE TROPICAL CYCLONE IN SOUTHIO
MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
---
WARNING POSITION:
211200Z --- NEAR 16.0S 100.4E
MOVEMENT PAST SIX HOURS - 265 DEGREES AT 09 KTS
POSITION ACCURATE TO WITHIN 060 NM
POSITION BASED ON CENTER LOCATED BY SATELLITE
PRESENT WIND DISTRIBUTION:
MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 025 NM NORTHEAST QUADRANT
030 NM SOUTHEAST QUADRANT
030 NM SOUTHWEST QUADRANT
025 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT
070 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
065 NM NORTHWEST QUADRANT
REPEAT POSIT: 16.0S 100.4E
---
FORECASTS:
12 HRS, VALID AT:
220000Z --- 16.1S 98.5E
MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT
025 NM SOUTHEAST QUADRANT
025 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 050 KT WINDS - 050 NM NORTHEAST QUADRANT
055 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
050 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT
070 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
VECTOR TO 24 HR POSIT: 265 DEG/ 10 KTS
---
24 HRS, VALID AT:
221200Z --- 16.2S 96.4E
MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 045 NM NORTHEAST QUADRANT
050 NM SOUTHEAST QUADRANT
055 NM SOUTHWEST QUADRANT
045 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 065 NM NORTHEAST QUADRANT
070 NM SOUTHEAST QUADRANT
085 NM SOUTHWEST QUADRANT
060 NM NORTHWEST QUADRANT
VECTOR TO 36 HR POSIT: 265 DEG/ 11 KTS
---
36 HRS, VALID AT:
230000Z --- 16.4S 94.1E
MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
045 NM SOUTHEAST QUADRANT
045 NM SOUTHWEST QUADRANT
040 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
080 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
VECTOR TO 48 HR POSIT: 265 DEG/ 12 KTS
---
EXTENDED OUTLOOK:
48 HRS, VALID AT:
231200Z --- 16.7S 91.6E
MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
WIND RADII VALID OVER OPEN WATER ONLY
RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT
020 NM SOUTHEAST QUADRANT
020 NM SOUTHWEST QUADRANT
020 NM NORTHWEST QUADRANT
RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT
065 NM SOUTHEAST QUADRANT
080 NM SOUTHWEST QUADRANT
055 NM NORTHWEST QUADRANT
---
REMARKS:
211500Z POSITION NEAR 16.0S 99.9E.
TROPICAL CYCLONE (TC) 22S (ILSA), LOCATED APPROXIMATELY 310 NM SOUTH-
EAST OF COCOS ISLAND, HAS TRACKED WESTWARD AT 09 KNOTS OVER THE PAST
SIX HOURS. THE CURRENT POSITION AND INTENSITY ESTIMATES ARE BASED ON
SATELLITE DVORAK FIXES FROM PGTW AND APRF. TC 22S HAS WEAKENED SLOWLY
OVER THE PAST 12 HOURS. A 211041Z SSMI-S IMAGE INDICATES THAT THE
BROKEN RING OF DEEP CONVECTION CONTINUES TO PERSIST, AND DRY AIR
CONTINUES TO WRAP AROUND THE SYSTEM. WITHIN THE NEXT 12 TO 24 HOURS
IT IS EXPECTED TO ISOLATE THE INNER CORE OF WARMER, MOISTER AIR AND
LEAD TO DEGRADATION OF THE LOW LEVEL CIRCULATION CENTER. SEA SURFACE
TEMPERATURES WILL CONTINUE TO DECREASE QUICKLY OVER THE NEXT 24
HOURS AND WILL BECOME UNFAVORABLE AFTER TAU 24. THE CYCLONE IS
TRACKING WESTWARD AND SLIGHTLY EQUATORWARD UNDER THE STEERING
INFLUENCE OF A CONTINUOUS, ZONALLY-ORIENTED SUBTROPICAL RIDGE TO THE
SOUTH. GENERALLY WESTWARD TO WEST-SOUTHWESTWARD MOTION IS EXPECTED TO
MAINTAIN THROUGH THE FORECAST PERIOD AS THE SUBTROPICAL RIDGE REMAINS
THE PRIMARY STEERING INFLUENCE. INCREASING VERTICAL WIND SHEAR WILL
DRIVE STEADY WEAKENING DURING THE NEXT 48 HOURS. MAXIMUM SIGNIFICANT
WAVE HEIGHT AT 211200Z IS 28 FEET. NEXT WARNINGS AT 220300Z AND
221500Z.//

NNNN

[HURAKAN]

Opening up.

[HURAKAN]

TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by PERTH TROPICAL CYCLONE WARNING CENTRE
at: 1231 UTC 21/03/2009
Name: Severe Tropical Cyclone Ilsa
Identifier: 18U
Data At: 1200 UTC
Latitude: 16.1S
Longitude: 100.9E
Location Accuracy: within 30 nm [55 km]
Movement Towards: west [262 deg]
Speed of Movement: 7 knots [14 km/h]
Maximum 10-Minute Wind: 80 knots [150 km/h]
Maximum 3-Second Wind Gust: 110 knots [205 km/h]
Central Pressure: 966 hPa
Radius of 34-knot winds NE quadrant: 60 nm [110 km]
Radius of 34-knot winds SE quadrant: 90 nm [165 km]
Radius of 34-knot winds SW quadrant: 90 nm [165 km]
Radius of 34-knot winds NW quadrant: 60 nm [110 km]
Radius of 48-knot winds NE quadrant: 40 nm [75 km]
Radius of 48-knot winds SE quadrant: 40 nm [75 km]
Radius of 48-knot winds SW quadrant: 40 nm [75 km]
Radius of 48-knot winds NW quadrant: 40 nm [75 km]
Radius of 64-knot winds: 25 nm [46 km]
Radius of Maximum Winds: 15 nm [28 km]
Dvorak Intensity Code: T4.5/5.0/W0.5/24HRS
Pressure of outermost isobar: 1006 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: 22/0000: 16.4S 99.4E: 060 [110]: 070 [130]: 975
+24: 22/1200: 16.7S 97.4E: 090 [165]: 060 [110]: 983
+36: 23/0000: 16.9S 95.0E: 120 [225]: 050 [095]: 991
+48: 23/1200: 17.3S 92.4E: 155 [285]: 045 [085]: 994
+60: 24/0000: 17.8S 89.8E: 200 [375]: 040 [075]: 997
+72: 24/1200: 19.0S 87.4E: 250 [465]: 035 [065]: 1000
REMARKS:
Eye no longer apparent on EIR or VIS imagery. Time averaged DT of 5.0 based on
EMBEDDED CENTRE pattern. The 24 hour trend is W- with the MET 4.5 and PAT 4.5.
Given the accuracy of intensity estimates using the embedded centre technique FT
based on MET/PAT and CI held at 5.0.

Decreasing MPI along the forecast track should see Ilsa gradually weaken over
the next 72 hours under light to moderate shear. There is strong agreement on a
general west to west southwest track during the next 72 hours under the
influence of the mid-level ridge to the south.

Copyright Commonwealth of Australia
==
The next bulletin for this system will be issued by: 21/1900 UTC by Perth TCWC.

[KWT]

Yep does seem to be weakening now with the southern side having something of a hard time, seems like the forecast for slow but steady weakening is pretty good.

[HURAKAN]

TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by PERTH TROPICAL CYCLONE WARNING CENTRE
at: 1841 UTC 21/03/2009
Name: Severe Tropical Cyclone Ilsa
Identifier: 18U
Data At: 1800 UTC
Latitude: 16.3S
Longitude: 100.1E
Location Accuracy: within 20 nm [37 km]
Movement Towards: west southwest [257 deg]
Speed of Movement: 7 knots [13 km/h]
Maximum 10-Minute Wind: 80 knots [150 km/h]
Maximum 3-Second Wind Gust: 110 knots [205 km/h]
Central Pressure: 967 hPa
Radius of 34-knot winds NE quadrant: 60 nm [110 km]
Radius of 34-knot winds SE quadrant: 90 nm [165 km]
Radius of 34-knot winds SW quadrant: 90 nm [165 km]
Radius of 34-knot winds NW quadrant: 60 nm [110 km]
Radius of 48-knot winds NE quadrant: 40 nm [75 km]
Radius of 48-knot winds SE quadrant: 40 nm [75 km]
Radius of 48-knot winds SW quadrant: 40 nm [75 km]
Radius of 48-knot winds NW quadrant: 40 nm [75 km]
Radius of 64-knot winds: 25 nm [46 km]
Radius of Maximum Winds: 15 nm [28 km]
Dvorak Intensity Code: T4.5/5.0/W0.5/24HRS
Pressure of outermost isobar: 1006 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: 16.7S 98.4E: 060 [110]: 060 [110]: 983
+24: 22/1800: 16.9S 96.2E: 090 [165]: 055 [100]: 987
+36: 23/0600: 17.1S 93.6E: 120 [225]: 050 [095]: 991
+48: 23/1800: 17.6S 91.0E: 155 [285]: 045 [085]: 994
+60: 24/0600: 18.4S 88.5E: 200 [375]: 040 [075]: 997
+72: 24/1800: 19.6S 86.3E: 250 [465]: 035 [065]: 999
REMARKS:
Eye no longer apparent on EIR or VIS imagery. Time averaged DT of 5.0 based on
EMBEDDED CENTRE pattern. The 24 hour trend is W- with the MET 4.5 and PAT 4.5.
Given the accuracy of intensity estimates using the embedded centre technique FT
based on MET/PAT and CI held at 5.0.

Decreasing MPI along the forecast track should see Ilsa gradually weaken over
the next 72 hours under light to moderate shear. There is strong agreement on a
general west to west southwest track during the next 72 hours under the
influence of the mid-level ridge to the south.

Copyright Commonwealth of Australia
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The next bulletin for this system will be issued by: 22/0100 UTC by Perth TCWC.

[KWT]

Still holding at 80kts so the idea of it weakening 20kts in 12hrs maybe a little agressive but we shall have to wait and see, either way weakening should still be occuring.