科科斯群岛东南四级强热带气旋“纳维尔”(08U/18S.Neville)

科科斯群岛东南四级强热带气旋“纳维尔”(08U/18S.Neville) - JTWC:115KT 东南印度洋

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ygsj24 楼主 W 2024-03-11 18:00:01

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AXAU01 APRF 110708
IDW27600
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE
at: 0708 UTC 11/03/2024
Name: Tropical Low  
Identifier: 08U
Data At: 0600 UTC
Latitude: 12.1S
Longitude: 101.6E
Location Accuracy: within 30nm (55 km)
Movement Towards: east (090 deg)
Speed of Movement: 13 knots (24 km/h)
Maximum 10-Minute Wind: 40 knots (75 km/h)
Maximum 3-Second Wind Gust: 55 knots (100 km/h)
Central Pressure: 995 hPa
Radius of 34-knot winds NE quadrant: 90 nm (165 km)
Radius of 34-knot winds SE quadrant: 
Radius of 34-knot winds SW quadrant: 
Radius of 34-knot winds NW quadrant: 150 nm (280 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:  nm ( km)
Radius of Maximum Winds:   nm (  km)
Dvorak Intensity Code: T1.0/2.0/S0.0/24HRS STT:W1.0/06HRS
Pressure of outermost isobar: 1006 hPa
Radius of outermost closed isobar: 180 nm (335 km)
FORECAST DATA
Date/Time    : Location    : Loc. Accuracy: Max Wind   : Central Pressure
(UTC)        : degrees     :      nm  (km): knots(km/h): hPa
+06:  11/1200: 12.3S 103.0E:     045 (085):  040  (075):  996
+12:  11/1800: 12.7S 104.4E:     060 (110):  045  (085):  993
+18:  12/0000: 13.2S 105.6E:     065 (120):  045  (085):  992
+24:  12/0600: 13.7S 106.7E:     070 (130):  045  (085):  992
+36:  12/1800: 14.6S 108.9E:     095 (175):  040  (075):  995
+48:  13/0600: 15.4S 110.9E:     120 (225):  040  (075):  995
+60:  13/1800: 16.1S 112.3E:     150 (275):  040  (075):  994
+72:  14/0600: 16.9S 113.3E:     170 (310):  045  (085):  992
+96:  15/0600: 18.0S 113.9E:     195 (360):  045  (085):  990
+120: 16/0600: 19.3S 113.4E:     240 (440):  055  (100):  983
REMARKS:
Tropical Low 08U continues to fight against easterly shear as monsoon gales
continue to the north of the system. 

The animated VIS imagery over the last 6 hours has shown a well-defined low
level vortex. However this seems transient in nature and the ASCAT-B imagery at
0302Z shows a very elongated centre, consistent with the broader VIS imagery. 
Moderate confidence in position based on ASCAT and animated imagery. 

Intensity at 40 knots based on ASCAT pass at 0302Z with gales restricted to the
northern quadrants. Dvorak analysis: DT 1.0 based on shear pattern (120nm
removed from the tight temperature gradient). MET/PAT 1.0 based on D 24h trend.
CI held at 2.0 due to restraints. No objective guidance available. 

08U has continued to track east associated with the strengthening monsoon in
the Indian Ocean. 08U is forecast to take a track to the southeast tonight and
for the remainder of the week. In the long term, 08U is forecast to recurve to
the southwest over the weekend under the influence of the mid level ridge, most
likely offshore of the Western Australian mainland. As Tropical Low 08U passes
to the south of Christmas Island tomorrow, heavy rain and strong to gale-force
winds are likely due to the strengthening monsoon flow. 

Sea surface temperatures along the track remain warm at about 29 degrees
Celsius. Easterly shear is forecast to limit the development of 08U throughout
the week, with only a moderate chance of tropical cyclone development forecast
through to Thursday. From Friday the shear may reduce enough and environment
remains generally favourable that the system develops into a tropical cyclone.
The chances may improve if the system is located a bit further south under the
upper ridge.  

Copyright Commonwealth of Australia
==
The next bulletin for this system will be issued by: 11/1330 UTC.

	Time (CXT)	Intensity Category	Latitude (decimal deg.)	Longitude (decimal deg.)	Estimated Position Accuracy (km)
0hr	1 pm March 11	tropical low	12.1S	101.6E	55
+6hr	7 pm March 11	tropical low	12.3S	103.0E	85
+12hr	1 am March 12	tropical low	12.7S	104.4E	110
+18hr	7 am March 12	tropical low	13.2S	105.6E	120
+24hr	1 pm March 12	tropical low	13.7S	106.7E	130
+36hr	1 am March 13	tropical low	14.6S	108.9E	175
+48hr	1 pm March 13	tropical low	15.4S	110.9E	225
+60hr	1 am March 14	tropical low	16.1S	112.3E	275
+72hr	1 pm March 14	tropical low	16.9S	113.3E	310

ygsj24 楼主 W 2024-03-11 18:00:02

0 12楼

WTXS32 PGTW 110900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 001//
REF/A/MSG/JOINT TYPHOON WRNCEN PEARL HARBOR HI/100852ZMAR2024//
AMPN/REF A IS A TROPICAL CYCLONE FORMATION ALERT.//
RMKS/
1. TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 001    
   02 ACTIVE TROPICAL CYCLONES IN SOUTHIO
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   110600Z --- NEAR 12.2S 101.3E
     MOVEMENT PAST SIX HOURS - 100 DEGREES AT 15 KTS
     POSITION ACCURATE TO WITHIN 050 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 - 155 NM NORTHEAST QUADRANT
                            080 NM SOUTHEAST QUADRANT
                            135 NM SOUTHWEST QUADRANT
                            225 NM NORTHWEST QUADRANT
   REPEAT POSIT: 12.2S 101.3E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   111800Z --- 12.7S 104.1E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 170 NM NORTHEAST QUADRANT
                            050 NM SOUTHEAST QUADRANT
                            100 NM SOUTHWEST QUADRANT
                            200 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 105 DEG/ 14 KTS
    ---
   24 HRS, VALID AT:
   120600Z --- 13.4S 106.8E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT
                            040 NM SOUTHEAST QUADRANT
                            070 NM SOUTHWEST QUADRANT
                            180 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 110 DEG/ 15 KTS
    ---
   36 HRS, VALID AT:
   121800Z --- 14.3S 109.7E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT
                            030 NM SOUTHEAST QUADRANT
                            060 NM SOUTHWEST QUADRANT
                            160 NM NORTHWEST QUADRANT
   VECTOR TO 48 HR POSIT: 110 DEG/ 14 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   130600Z --- 15.3S 112.5E
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 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 - 130 NM NORTHEAST QUADRANT
                            040 NM SOUTHEAST QUADRANT
                            060 NM SOUTHWEST QUADRANT
                            160 NM NORTHWEST QUADRANT
   VECTOR TO 72 HR POSIT: 110 DEG/ 07 KTS
    ---
   72 HRS, VALID AT:
   140600Z --- 16.2S 115.4E
   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 - 100 NM NORTHEAST QUADRANT
                            050 NM SOUTHEAST QUADRANT
                            090 NM SOUTHWEST QUADRANT
                            140 NM NORTHWEST QUADRANT
   VECTOR TO 96 HR POSIT: 150 DEG/ 03 KTS
    ---
   LONG RANGE OUTLOOK:
    ---
   96 HRS, VALID AT:
   150600Z --- 17.1S 116.0E
   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 - 120 NM NORTHEAST QUADRANT
                            060 NM SOUTHEAST QUADRANT
                            110 NM SOUTHWEST QUADRANT
                            140 NM NORTHWEST QUADRANT
   VECTOR TO 120 HR POSIT: 210 DEG/ 03 KTS
    ---
   120 HRS, VALID AT:
   160600Z --- 18.0S 115.5E
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
                            040 NM SOUTHEAST QUADRANT
                            040 NM SOUTHWEST QUADRANT
                            040 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT
                            080 NM SOUTHEAST QUADRANT
                            120 NM SOUTHWEST QUADRANT
                            120 NM NORTHWEST QUADRANT
    ---
REMARKS:
110900Z POSITION NEAR 12.3S 102.0E.
11MAR24. TROPICAL CYCLONE 18S (EIGHTEEN), LOCATED APPROXIMATELY
950 NM NORTHWEST OF LEARMONTH, AUSTRALIA, HAS TRACKED EASTWARD AT
15 KNOTS OVER THE PAST SIX HOURS. MINIMUM CENTRAL PRESSURE AT
110600Z IS 999 MB. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 110600Z IS
24 FEET. NEXT WARNINGS AT 111500Z, 112100Z, 120300Z AND 120900Z.
REFER TO TROPICAL CYCLONE 17S (FILIPO) WARNINGS (WTXS31 PGTW) 
FOR TWELVE-HOURLY UPDATES.
2. THIS CANCELS AND SUPERSEDES REF A (WTXS22 PGTW 100900).//
NNNN

WDXS32 PGTW 110900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 18S (EIGHTEEN)
WARNING NR 001//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 12.2S 101.3E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 950 NM NORTHWEST OF LEARMONTH, AUSTRALIA
   MOVEMENT PAST 6 HOURS: EASTWARD AT 15 KTS
   SIGNIFICANT WAVE HEIGHT: 24 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
TROPICAL CYCLONE (TC) 18S HAS CONTINUED TO STRUGGLE TO DEVELOP DUE
TO HIGH (30-40 KNOTS) EASTERLY VERTICAL WIND SHEAR AS EVIDENCED IN
THE ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI), WHICH DEPICTS A
FULLY-EXPOSED LOW-LEVEL CIRCULATION (LLC) WITH PERSISTENT AND DEEP
CONVECTION SHEARED OVER THE WESTERN QUADRANT. ALTHOUGH THE DEEP
CONVECTIVE STRUCTURE IS WEAK, THE LOW-LEVEL BANDING IS DEFINED AND
WRAPS NEATLY INTO THE CENTER, AS EVIDENT IN THE 110209Z MHS 89 GHZ
MICROWAVE IMAGE. HOWEVER, AN 110304Z ASCAT-C IMAGE HAS CONTINUED TO
CONFIRM A BROAD CENTER WITH EXTENSIVE GALE-FORCE WINDS (35-45
KNOTS) DISPLACED ALONG THE PERIPHERY. THIS EXTENSIVE WIND FIELD IS
REFLECTED IN THE WIND RADII ANALYSIS. THE INITIAL POSITION IS
PLACED WITH HIGH CONFIDENCE BASED ON MSI, AND THE AFOREMENTIONED
ASCAT IMAGE. THE INITIAL INTENSITY OF 40 KTS IS ASSESSED WITH HIGH
CONFIDENCE BASED ON THE ASCAT DATA.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: NEAR-EQUATORIAL RIDGE (NER) POSITIONED TO
THE NORTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   KNES: T2.0 - 30 KTS
   APRF: T2.0 - 30 KTS

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY
UNFAVORABLE
   VWS: 30-40 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE WESTWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   INITIAL WIND RADII: HIGH

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THIS INITIAL PROGNOSTIC REASONING
MESSAGE ESTABLISHES THE FORECAST PHILOSOPHY.

FORECAST DISCUSSION: TC 18S IS FORECAST TO TRACK EAST-SOUTHEASTWARD
THROUGH TAU 72 UNDER THE STEERING INFLUENCE OF THE NER. AFTER TAU 72,
THE SYSTEM WILL SLOW, POSSIBLY BECOMING QUASI-STATIONARY, AS THE
STEERING INFLUENCE GRADUALLY TRANSITIONS TO A BUILDING STR OVER
AUSTRALIA. THE SYSTEM SHOULD TURN SOUTH-SOUTHWESTWARD BY TAU 120
ALONG THE NORTHWESTERN PERIPHERY OF THE AFOREMENTIONED STR. THE
SYSTEM WILL INTENSIFY SLOWLY THROUGH TAU 48, WITH A SLIGHTLY FASTER
INTENSIFICATION RATE THROUGH TAU 96 DUE TO IMPROVING POLEWARD OUTFLOW.
AFTER TAU 96, THE SYSTEM WILL BEGIN TO INTERACT WITH A MAJOR SHORTWAVE
TROUGH, WHICH SHOULD LEAD TO A SLIGHT WEAKENING TREND.   

MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN FAIR AGREEMENT
THROUGH TAU 72 WITH A 200 NM CROSS-TRACK SPREAD AT TAU 72. AFTER
TAU 72, THE NUMERICAL MODEL GUIDANCE DIVERGES SIGNIFICANTLY DUE TO
COMPETING STEERING MECHANISMS, LENDING LOW CONFIDENCE TO THE JTWC
EXTENDED FORECAST. THE 110000Z ECMWF ENSEMBLE (EPS) INDICATES A
VERY LARGE SPREAD IN SOLUTIONS AND HIGH UNCERTAINTY IN THE TAU 72
TO TAU 120 PERIOD. RELIABLE INTENSITY GUIDANCE INDICATES FAIR
AGREEMENT THROUGH THE FORECAST PERIOD WITH A STEADY INTENSIFICATION
TREND. 

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: MEDIUM
   TRACK 72-120 HR: LOW
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
NNNN

ygsj24 楼主 W 2024-03-11 20:42:47

0 13楼

AXAU01 APRF 111321
IDW27600
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE
at: 1321 UTC 11/03/2024
Name: Tropical Low  
Identifier: 08U
Data At: 1200 UTC
Latitude: 11.9S
Longitude: 102.5E
Location Accuracy: within 40nm (75 km)
Movement Towards: east (090 deg)
Speed of Movement: 9 knots (17 km/h)
Maximum 10-Minute Wind: 40 knots (75 km/h)
Maximum 3-Second Wind Gust: 55 knots (100 km/h)
Central Pressure: 994 hPa
Radius of 34-knot winds NE quadrant: 120 nm (220 km)
Radius of 34-knot winds SE quadrant: 
Radius of 34-knot winds SW quadrant: 
Radius of 34-knot winds NW quadrant: 150 nm (280 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:  nm ( km)
Radius of Maximum Winds:   nm (  km)
Dvorak Intensity Code: T1.5/2.0/S0.0/24HRS STT:D0.5/06HRS
Pressure of outermost isobar: 1006 hPa
Radius of outermost closed isobar: 180 nm (335 km)
FORECAST DATA
Date/Time    : Location    : Loc. Accuracy: Max Wind   : Central Pressure
(UTC)        : degrees     :      nm  (km): knots(km/h): hPa
+06:  11/1800: 12.3S 103.9E:     055 (100):  045  (085):  992
+12:  12/0000: 12.8S 105.2E:     065 (120):  045  (085):  993
+18:  12/0600: 13.3S 106.3E:     070 (130):  045  (085):  992
+24:  12/1200: 13.7S 107.6E:     075 (145):  045  (085):  992
+36:  13/0000: 14.6S 109.8E:     095 (180):  040  (075):  995
+48:  13/1200: 15.5S 111.6E:     125 (235):  040  (075):  995
+60:  14/0000: 16.2S 112.8E:     150 (275):  040  (075):  994
+72:  14/1200: 16.9S 113.4E:     155 (290):  045  (085):  992
+96:  15/1200: 18.3S 113.7E:     180 (335):  050  (095):  987
+120: 16/1200: 19.6S 113.1E:     235 (440):  055  (100):  982
REMARKS:
Tropical Low 08U continues to fight against easterly shear as monsoon gales
continue to the north of the system.

Animated VIS imagery prior to sunset showed a well-defined low level exposed
circulation with deep convection displaced to the northwest. Scatterometry
however continues to show a broad, elongated circulation. Confidence in the
analysis position is poor due to the deep convection being displaced from the
LLCC which is difficult to resolve on overnight IR imagery 

Intensity has been maintained at 40 knots based on earlier scatterometry passes
though gales remain restricted to the northern quadrants. Dvorak analysis: DT
1.5 based on shear pattern with the LLCC around 60nm from strong T gradient.
MET/PAT 1.5 based on S 24h trend. FT 1.5 based on PAT. CI held at 2.0. No
objective guidance available. 

08U is a relatively shallow system that continues to track east with the
low-level monsoon flow and is limited by easterly shear. Environmental
conditions are otherwise favourable and it is likely to slowly become deeper.
As the influence of a mid-level ridge then increases it is expected to turn to
the south from Thursday. Gales would then be less due to the monsoon influence,
becoming confined closer to the system centre and likely extending into the
southern quadrants. It could then strengthen further if it is able to move
further south and under the upper ridge.  

It will most likely remain offshore of the Western Australian coast as it moves
to the southwest over the weekend. There is however a large spread in how far
east the system moves prior to turning back towards the southwest. 

Sea surface temperatures along the track remain warm at about 28-29 degrees
Celsius.

Copyright Commonwealth of Australia
==
The next bulletin for this system will be issued by: 11/1930 UTC.

	Time (CXT)	Intensity Category	Latitude (decimal deg.)	Longitude (decimal deg.)	Estimated Position Accuracy (km)
0hr	7 pm March 11	tropical low	11.9S	102.5E	75
+6hr	1 am March 12	tropical low	12.3S	103.9E	100
+12hr	7 am March 12	tropical low	12.8S	105.2E	120
+18hr	1 pm March 12	tropical low	13.3S	106.3E	130
+24hr	7 pm March 12	tropical low	13.7S	107.6E	145
+36hr	7 am March 13	tropical low	14.6S	109.8E	180
+48hr	7 pm March 13	tropical low	15.5S	111.6E	235
+60hr	7 am March 14	tropical low	16.2S	112.8E	275
+72hr	7 pm March 14	tropical low	16.9S	113.4E	290

最后于 2024-03-11 21:25:00 被ygsj24编辑，原因：

ygsj24 楼主 W 2024-03-12 04:10:01

0 14楼

AXAU01 APRF 111848
IDW27600
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE
at: 1848 UTC 11/03/2024
Name: Tropical Low  
Identifier: 08U
Data At: 1800 UTC
Latitude: 12.4S
Longitude: 104.2E
Location Accuracy: within 35nm (65 km)
Movement Towards: east (097 deg)
Speed of Movement: 13 knots (24 km/h)
Maximum 10-Minute Wind: 40 knots (75 km/h)
Maximum 3-Second Wind Gust: 55 knots (100 km/h)
Central Pressure: 996 hPa
Radius of 34-knot winds NE quadrant: 120 nm (220 km)
Radius of 34-knot winds SE quadrant: 
Radius of 34-knot winds SW quadrant: 
Radius of 34-knot winds NW quadrant: 140 nm (260 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:  nm ( km)
Radius of Maximum Winds:   nm (  km)
Dvorak Intensity Code: T2.0/2.0/S0.0/24HRS STT:D0.5/06HRS
Pressure of outermost isobar: 1008 hPa
Radius of outermost closed isobar: 140 nm (260 km)
FORECAST DATA
Date/Time    : Location    : Loc. Accuracy: Max Wind   : Central Pressure
(UTC)        : degrees     :      nm  (km): knots(km/h): hPa
+06:  12/0000: 12.9S 105.5E:     050 (090):  045  (085):  994
+12:  12/0600: 13.4S 106.7E:     055 (105):  040  (075):  997
+18:  12/1200: 13.8S 107.9E:     065 (120):  045  (080):  996
+24:  12/1800: 14.2S 109.0E:     075 (135):  040  (075):  997
+36:  13/0600: 15.2S 111.0E:     095 (170):  040  (075):  997
+48:  13/1800: 15.9S 112.5E:     130 (240):  040  (075):  996
+60:  14/0600: 16.7S 113.4E:     150 (275):  045  (085):  993
+72:  14/1800: 17.4S 113.9E:     165 (305):  045  (085):  994
+96:  15/1800: 18.7S 113.8E:     200 (365):  050  (095):  988
+120: 16/1800: 20.0S 113.1E:     260 (485):  055  (100):  984
REMARKS:
Deep convection remains confined to the northwest quadrant of Tropical Low 08U. 

Position is based on animated enhanced IR imagery and recent movement since
that last SSMIS microwave pass at 11:49Z. Overnight scatterometry pass missed
the low level centre but confirmed that gales do not extend beyond 120nmi to
the northeast. Confidence in the analysis position is fair due to the deep
convection being displaced from the low level centre.  

Intensity has been maintained at 40 knots based on earlier scatterometry passes
though gales remain restricted to the northern quadrants. Dvorak analysis: DT
2.5 based on shear pattern with the LLCC around 40nm from strong T gradient.
MET 2.5 based on D- 24h trend and PAT adjusted to 2.0. FT 2.0 based on PAT, CI
2.0. Objective guidance: ADT 35kt, AiDT 36kt (1-min average). 

08U is a relatively shallow system that continues to track east with the
low-level monsoon flow and is limited by easterly shear. Environmental
conditions are otherwise favourable with SSTs of 28 to 29 degrees Celcius along
the track. 08U is forecast to slowly become a deeper tropical low through the
week.  

As the influence of a mid-level ridge then increases it is expected to turn to
the south from Thursday. Thursday into Friday, gales are likely to become more
confined to the system centre and are forecast to extend into the southern
quadrants of 08U. It is forecast to intensify into the weekend as it tracks
south under the upper ridge. 

It will most likely remain offshore of the Western Australian coast as it moves
to the southwest over the weekend. There is however a large spread in how far
east the system moves prior to turning back towards the southwest and 08U may
approach the coast over the weekend. 

Copyright Commonwealth of Australia
==
The next bulletin for this system will be issued by: 12/0130 UTC.

	Time (CXT)	Intensity Category	Latitude (decimal deg.)	Longitude (decimal deg.)	Estimated Position Accuracy (km)
0hr	1 am March 12	tropical low	12.4S	104.2E	65
+6hr	7 am March 12	tropical low	12.9S	105.5E	90
+12hr	1 pm March 12	tropical low	13.4S	106.7E	105
+18hr	7 pm March 12	tropical low	13.8S	107.9E	120
+24hr	1 am March 13	tropical low	14.2S	109.0E	135
+36hr	1 pm March 13	tropical low	15.2S	111.0E	170
+48hr	1 am March 14	tropical low	15.9S	112.5E	240
+60hr	1 pm March 14	tropical low	16.7S	113.4E	275
+72hr	1 am March 15	1	17.4S	113.9E	305

ygsj24 楼主 W 2024-03-12 04:10:02

0 15楼

WTXS32 PGTW 112100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 003//
RMKS/
1. TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 003    
   02 ACTIVE TROPICAL CYCLONES IN SOUTHIO
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   111800Z --- NEAR 12.1S 104.4E
     MOVEMENT PAST SIX HOURS - 095 DEGREES AT 18 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 - 155 NM NORTHEAST QUADRANT
                            080 NM SOUTHEAST QUADRANT
                            135 NM SOUTHWEST QUADRANT
                            225 NM NORTHWEST QUADRANT
   REPEAT POSIT: 12.1S 104.4E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   120600Z --- 13.0S 107.1E
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT
                            070 NM SOUTHEAST QUADRANT
                            100 NM SOUTHWEST QUADRANT
                            200 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 105 DEG/ 14 KTS
    ---
   24 HRS, VALID AT:
   121800Z --- 13.8S 109.8E
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT
                            070 NM SOUTHEAST QUADRANT
                            070 NM SOUTHWEST QUADRANT
                            170 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 105 DEG/ 11 KTS
    ---
   36 HRS, VALID AT:
   130600Z --- 14.4S 112.0E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT
                            100 NM SOUTHEAST QUADRANT
                            100 NM SOUTHWEST QUADRANT
                            170 NM NORTHWEST QUADRANT
   VECTOR TO 48 HR POSIT: 110 DEG/ 10 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   131800Z --- 15.0S 113.9E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT
                            110 NM SOUTHEAST QUADRANT
                            090 NM SOUTHWEST QUADRANT
                            150 NM NORTHWEST QUADRANT
   VECTOR TO 72 HR POSIT: 120 DEG/ 05 KTS
    ---
   72 HRS, VALID AT:
   141800Z --- 15.9S 115.7E
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT
                            000 NM SOUTHEAST QUADRANT
                            000 NM SOUTHWEST QUADRANT
                            000 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT
                            130 NM SOUTHEAST QUADRANT
                            090 NM SOUTHWEST QUADRANT
                            130 NM NORTHWEST QUADRANT
   VECTOR TO 96 HR POSIT: 150 DEG/ 03 KTS
    ---
   LONG RANGE OUTLOOK:
    ---
   96 HRS, VALID AT:
   151800Z --- 16.9S 116.3E
   MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT
                            060 NM SOUTHEAST QUADRANT
                            050 NM SOUTHWEST QUADRANT
                            050 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT
                            140 NM SOUTHEAST QUADRANT
                            110 NM SOUTHWEST QUADRANT
                            110 NM NORTHWEST QUADRANT
   VECTOR TO 120 HR POSIT: 180 DEG/ 03 KTS
    ---
   120 HRS, VALID AT:
   161800Z --- 18.0S 116.3E
   MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 070 NM NORTHEAST QUADRANT
                            070 NM SOUTHEAST QUADRANT
                            060 NM SOUTHWEST QUADRANT
                            050 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT
                            140 NM SOUTHEAST QUADRANT
                            130 NM SOUTHWEST QUADRANT
                            110 NM NORTHWEST QUADRANT
    ---
REMARKS:
112100Z POSITION NEAR 12.3S 105.1E.
11MAR24. TROPICAL CYCLONE 18S (EIGHTEEN), LOCATED APPROXIMATELY
826 NM NORTHWEST OF LEARMONTH, AUSTRALIA, HAS TRACKED EASTWARD AT
18 KNOTS OVER THE PAST SIX HOURS. MINIMUM CENTRAL PRESSURE AT 111800Z 
IS 999 MB. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 111800Z IS 23 FEET. NEXT 
WARNINGS AT 120900Z AND 122100Z. REFER TO TROPICAL CYCLONE 17S 
(FILIPO) WARNINGS (WTXS31 PGTW) FOR TWELVE-HOURLY UPDATES.//
NNNN

WDXS32 PGTW 112100
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 18S (EIGHTEEN) WARNING 
NR 003//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 12.1S 104.4E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 826 NM NORTHWEST OF LEARMONTH, AUSTRALIA
   MOVEMENT PAST 6 HOURS: EASTWARD AT 18 KTS
   SIGNIFICANT WAVE HEIGHT: 23 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL
CYCLONE 18S WITH A BROAD AND PARTIALLY EXPOSED LOWER-LEVEL
CIRCULATION CENTER (LLCC) WITH FLARING DEEP-LAYER CONVECTION
LIMITED TO THE NORTHWEST SECTOR DUE TO HIGH EASTERLY SHEAR. MOIST
AIR FROM THE NORTHWEST ENTRAINS INTO THE SYSTEM AS INDICATED BY
CLOUD BANDS WRAPPING INTO THE CENTER OF THE CYCLONE. THE
ENVIRONMENT IS MARGINALLY FAVORABLE WITH MODERATE VERTICAL WIND
SHEAR FROM THE EAST AT 20-25KTS, WARM SEA SURFACE TEMPERATURE (SST)
OF 29-30C, AND MODERATE WESTWARD OUTFLOW IN THE EASTERN SEMI-CIRCLE
OF THE SYSTEM. THE INITIAL POSITION WAS BASED ON GOES-IO EIR AND
SHORTWAVE INFRARED (SWIR) REVEALING A PARTIALLY EXPOSED AND BROAD
LLCC. THE INITIAL INTENSITY WAS DETERMINED BASED ON AGENCY AND
OBJECTIVE FIXES LISTED BELOW. THE PRIMARY STEERING INFLUENCE AT THE
MOMENT IS THE STRONG NEAR EQUATORIAL RIDGE (NER) CENTERED OVER
BORNEO, AND THE ACCOMPANYING DEEP WESTERLIES ALONG THE INDONESIAN
ISLANDS. HOWEVER, THERE IS A RELATIVELY DEEP TROUGH IN PLACE TO THE
SOUTH, WHICH AS OF YET IS NOT INFLUENCING THE TRACK BUT REMAINS A
POTENTIAL INFLUENCER DOWN THE ROAD.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: ON THE SOUTHERN PERIPHERY OF A NEAR
EQUATORIAL RIDGE (NER) TO THE NORTH. 

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   KNES: T1.5 - 25 KTS
   APRF: T2.0 - 30 KTS
   CIMSS ADT: 35 KTS AT 111730Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL
   VWS: 25-30 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE WESTWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: LOW
   INITIAL WIND RADII: LOW

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TC 18S IS FORECAST TO TRACK EAST-SOUTHEAST
OVER THE NEXT 72 HOURS WHILE UNDER THE STEERING INFLUENCE OF A NER
TO THE NORTH. FROM TAU 72 ONWARDS, THE TRACK BECOMES HIGHLY
UNCERTAIN DUE TO SIGNIFICANT DIFFERENCES IN THE EVOLUTION OF A
SUBTROPICAL RIDGE (STR) ANTICIPATED TO DEVELOP OVER CENTRAL
AUSTRALIA. AS THE RIDGE DEVELOPS OVER THE CONTINENT, PRIMARILY TO
THE SOUTH OF TC 18S, IT WILL TEND TO BLOCK THE SYSTEM FROM MOVING
FURTHER EAST, AND TEND TO SLOW IT DOWN AS IT APPROACHES THE
NORTHWEST COAST OF AUSTRALIA. A SLOW CURVE TOWARDS THE SOUTH IS
EXPECTED BY THE END OF THE FORECAST PERIOD AS THE SYSTEM MOVES
TOWARDS A BREAK IN THE STR. TC 18S IS FORECAST TO INTENSIFY SLOWLY
BUT STEADILY OVER THE FORECAST PERIOD AS IT STRUGGLES IN THE
NEAR-TERM AGAINST SIGNIFICANT EASTERLY SHEAR (20-25KTS). A FASTER
RATE OF INTENSIFICATION IS EXPECTED BY THE END OF THE FORECAST AS
SHEAR IS FORECAST TO WEAKEN, THOUGH THE RESTRAINED OUTFLOW
ENVIRONMENT SHOULD KEEP A LID ON THE INTENSIFICATION. OTHERWISE,
CONDITIONS ARE ANTICIPATED TO BE FAVORABLE AS THE ENVIRONMENT
REMAINS MOIST AND SEA SURFACE TEMPERATURES ARE EXPECTED TO REMAIN
BETWEEN 29-30C.

MODEL DISCUSSION: JTWC CONSENSUS TRACK MODEL GUIDANCE IS IN GOOD
AGREEMENT IN THE NEAR-TERM, THAT THE STORM WILL TRACK TO THE
WEST-SOUTHWEST OVER THE NEXT 36 HOURS, HOWEVER CROSS-TRACK SPREAD
BEGINS TO OPEN EXPONENTIALLY BEYOND TAU 36. BY TAU 120, THE
CROSS-TRACK SPREAD OPENS TO 1050NM, WITH GALWEM MARKING THE
SOUTHERN EXTENT AND GFS MARKING THE NORTH. CONSENSUS GUIDANCE TENDS
TO PREFER A MORE SOUTHERLY AND SLOWER ROUTE THAN GFS. LARGE
DIFFERENCES IN THE STEERING MECHANISM BEYOND TAU 72 ARE REPRESENTED
IN HOW THE RIDGE OVER AUSTRALIA DEVELOPS; GFS SHOWS THE RIDGE
EXTENDING WESTWARD TO THE SOUTH OF THE SYSTEM, ALLOWING THE SYSTEM
TO TRACK MORE EASTWARD AND CLOSER TO THE COAST NEAR BROOME.
MEANWHILE THE ECMWF GUIDANCE SHOWS THE RIDGE BUILDING AS ONE LARGER
RIDGE TO THE EAST, WHICH WOULD FORCE THE SYSTEM TO TURN TO THE
SOUTH-SOUTHWEST MUCH SOONER IN THE FORECAST PERIOD, BEING IN
GENERAL SIMILAR TO THE OTHER MODELS SUCH AS NAVGEM AND THE UKMET.
THE JTWC FORECAST TRACK LIES ON THE NORTHERN EDGE OF THE GUIDANCE
ENVELOPE THROUGH TAU 72, THEN REMAINS EAST OF THE CONSENSUS AND THE
MAJORITY OF THE GUIDANCE, EXCEPT GFS, THROUGH TAU 120. ENSEMBLE
GUIDANCE ALSO SHOWS AN EXTREME AMOUNT OF UNCERTAINTY, WITH A VERY
WIDE SPREAD IN THE TRACKS. WITH SUCH HIGH UNCERTAINTY, THE JTWC
FORECAST IS SET WITH LOW CONFIDENCE THROUGH THE FORECAST PERIOD.
JTWC INTENSITY CONSENSUS GUIDANCE CONSISTENTLY AND STEADILY
INCREASES TO 50-65KTS BY THE END OF THE FORECAST PERIOD, WITH
MINIMAL SPREAD ACROSS THE GUIDANCE PACKAGE. HOWEVER, IN LIGHT OF
TRACK UNCERTAINTY AND THE IMPACT OF TRACK CHANGES ON THE POTENTIAL
INTENSITY, THE INTENSITY FORECAST IS SET WITH LOW CONFIDENCE.  

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: LOW
   TRACK 72-120 HR: LOW
   INTENSITY 0 - 72 HR: LOW
   INTENSITY 72-120 HR: LOW//
NNNN

最后于 2024-03-12 06:00:00 被ygsj24编辑，原因：

ygsj24 楼主 W 2024-03-12 18:00:01

0 16楼

AXAU01 APRF 120046
IDW27600
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE
at: 0046 UTC 12/03/2024
Name: Tropical Low  
Identifier: 08U
Data At: 0000 UTC
Latitude: 13.3S
Longitude: 105.6E
Location Accuracy: within 30nm (55 km)
Movement Towards: east southeast (112 deg)
Speed of Movement: 15 knots (27 km/h)
Maximum 10-Minute Wind: 40 knots (75 km/h)
Maximum 3-Second Wind Gust: 55 knots (100 km/h)
Central Pressure: 996 hPa
Radius of 34-knot winds NE quadrant: 120 nm (220 km)
Radius of 34-knot winds SE quadrant: 
Radius of 34-knot winds SW quadrant: 
Radius of 34-knot winds NW quadrant: 140 nm (260 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:  nm ( km)
Radius of Maximum Winds:   nm (  km)
Dvorak Intensity Code: T1.5/2.0/W0.5/24HRS STT:W0.5/06HRS
Pressure of outermost isobar: 1006 hPa
Radius of outermost closed isobar: 180 nm (335 km)
FORECAST DATA
Date/Time    : Location    : Loc. Accuracy: Max Wind   : Central Pressure
(UTC)        : degrees     :      nm  (km): knots(km/h): hPa
+06:  12/0600: 13.7S 107.1E:     045 (085):  040  (075):  995
+12:  12/1200: 14.0S 108.4E:     055 (105):  040  (075):  995
+18:  12/1800: 14.4S 109.8E:     065 (120):  040  (075):  995
+24:  13/0000: 14.8S 111.1E:     075 (140):  040  (075):  995
+36:  13/1200: 15.6S 113.3E:     100 (180):  040  (075):  995
+48:  14/0000: 16.4S 114.7E:     130 (240):  040  (075):  994
+60:  14/1200: 17.3S 115.4E:     155 (290):  045  (085):  991
+72:  15/0000: 17.9S 115.3E:     175 (320):  045  (085):  992
+96:  16/0000: 19.0S 114.4E:     190 (350):  055  (100):  984
+120: 17/0000: 20.1S 113.5E:     275 (505):  060  (110):  978
REMARKS:
Deep convection remains confined well to the northwest of an exposed low level
circulation centre of Tropical Low 08U.  

Position is based on animated VIS imagery, persistence and recent microwave
passes. Confidence in the analysis position is good.  

Intensity is maintained at 40 knots based on earlier scatterometry passes,
though gales remain restricted to the northern quadrant. Dvorak analysis is
based on MET=1.5 on a W- 24h trend. DT is inclusive as the LLCC is more than
90nm from deepest convection. CI is held at 2.0. Objective guidance: ADT 33kt,
AiDT 31kt, DPRINT 28kt (1-min average). 

08U is a shallow system that continues to track east with the low-level monsoon
flow and is limited by 22kt easterly shear. Environmental conditions are
otherwise favourable with SSTs 28-29C along track, decent monsoon flow to the
north and reasonable upper level divergence.  

08U is forecast to slowly become a deeper system during the week. Once this
happens, the influence of the mid-level ridge over Australia would then
increase and 08U is expected to turn towards the south. Gales are likely to
become more confined to the system centre and are forecast to extend into the
southern quadrants of 08U from Thursday. It is forecast to intensify into the
weekend as it tracks south under the influence of the ridge. 

The most likely track scenario keeps 08U off the coast of Western Australian as
it curves towards the southwest over the weekend. There is however a large
spread in the guidance in the longer term. A small number of guidance keeps the
system as a shallow low and track it further east, before developing it. If
this happens, then 08U is likely to be closer to the coast as it turns towards
the southwest over the weekend. In any case, there could be possible impacts
along the Pilbara coast due to its proximity to the coast.  

Copyright Commonwealth of Australia
==
The next bulletin for this system will be issued by: 12/0730 UTC.

	Time (CXT)	Intensity Category	Latitude (decimal deg.)	Longitude (decimal deg.)	Estimated Position Accuracy (km)
0hr	7 am March 12	tropical low	13.3S	105.6E	55
+6hr	1 pm March 12	tropical low	13.7S	107.1E	85
+12hr	7 pm March 12	tropical low	14.0S	108.4E	105
+18hr	1 am March 13	tropical low	14.4S	109.8E	120
+24hr	7 am March 13	tropical low	14.8S	111.1E	140
+36hr	7 pm March 13	tropical low	15.6S	113.3E	180
+48hr	7 am March 14	tropical low	16.4S	114.7E	240
+60hr	7 pm March 14	tropical low	17.3S	115.4E	290
+72hr	7 am March 15	1	17.9S	115.3E	320

ygsj24 楼主 W 2024-03-12 18:00:01

0 17楼

WTXS32 PGTW 120300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 004//
RMKS/
1. TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 004
   02 ACTIVE TROPICAL CYCLONES IN SOUTHIO
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   120000Z --- NEAR 13.4S 105.5E
     MOVEMENT PAST SIX HOURS - 140 DEGREES AT 17 KTS
     POSITION ACCURATE TO WITHIN 060 NM
     POSITION BASED ON CENTER LOCATED BY SATELLITE
   PRESENT WIND DISTRIBUTION:
   MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 155 NM NORTHEAST QUADRANT
                            080 NM SOUTHEAST QUADRANT
                            135 NM SOUTHWEST QUADRANT
                            225 NM NORTHWEST QUADRANT
   REPEAT POSIT: 13.4S 105.5E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   121200Z --- 14.2S 108.2E
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT
                            110 NM SOUTHEAST QUADRANT
                            100 NM SOUTHWEST QUADRANT
                            250 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 105 DEG/ 13 KTS
    ---
   24 HRS, VALID AT:
   130000Z --- 14.8S 110.8E
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT
                            100 NM SOUTHEAST QUADRANT
                            070 NM SOUTHWEST QUADRANT
                            210 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 110 DEG/ 09 KTS
    ---
   36 HRS, VALID AT:
   131200Z --- 15.5S 112.6E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT
                            130 NM SOUTHEAST QUADRANT
                            100 NM SOUTHWEST QUADRANT
                            180 NM NORTHWEST QUADRANT
   VECTOR TO 48 HR POSIT: 115 DEG/ 07 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   140000Z --- 16.1S 114.0E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT
                            140 NM SOUTHEAST QUADRANT
                            090 NM SOUTHWEST QUADRANT
                            160 NM NORTHWEST QUADRANT
   VECTOR TO 72 HR POSIT: 120 DEG/ 04 KTS
    ---
   72 HRS, VALID AT:
   150000Z --- 17.0S 115.5E
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT
                            000 NM SOUTHEAST QUADRANT
                            000 NM SOUTHWEST QUADRANT
                            000 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT
                            150 NM SOUTHEAST QUADRANT
                            100 NM SOUTHWEST QUADRANT
                            130 NM NORTHWEST QUADRANT
   VECTOR TO 96 HR POSIT: 160 DEG/ 03 KTS
    ---
   LONG RANGE OUTLOOK:
    ---
   96 HRS, VALID AT:
   160000Z --- 18.0S 115.9E
   MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 070 NM NORTHEAST QUADRANT
                            070 NM SOUTHEAST QUADRANT
                            060 NM SOUTHWEST QUADRANT
                            060 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 150 NM NORTHEAST QUADRANT
                            160 NM SOUTHEAST QUADRANT
                            120 NM SOUTHWEST QUADRANT
                            120 NM NORTHWEST QUADRANT
   VECTOR TO 120 HR POSIT: 175 DEG/ 03 KTS
    ---
   120 HRS, VALID AT:
   170000Z --- 19.1S 116.0E
   MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 064 KT WINDS - 040 NM NORTHEAST QUADRANT
                            040 NM SOUTHEAST QUADRANT
                            030 NM SOUTHWEST QUADRANT
                            030 NM NORTHWEST QUADRANT
   RADIUS OF 050 KT WINDS - 080 NM NORTHEAST QUADRANT
                            080 NM SOUTHEAST QUADRANT
                            080 NM SOUTHWEST QUADRANT
                            070 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 160 NM NORTHEAST QUADRANT
                            170 NM SOUTHEAST QUADRANT
                            150 NM SOUTHWEST QUADRANT
                            140 NM NORTHWEST QUADRANT
    ---
REMARKS:
120300Z POSITION NEAR 13.6S 106.2E.
12MAR24. TROPICAL CYCLONE 18S (EIGHTEEN), LOCATED APPROXIMATELY
725 NM NORTHWEST OF LEARMONTH, AUSTRALIA, HAS TRACKED SOUTHEASTWARD AT
17 KNOTS OVER THE PAST SIX HOURS. MINIMUM CENTRAL PRESSURE AT 120000Z
IS 1000 MB. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 120000Z IS 20 FEET.
NEXT WARNINGS AT 121500Z AND 130300Z. REFER TO TROPICAL CYCLONE 17S
(FILIPO) WARNINGS (WTXS31 PGTW) FOR TWELVE-HOURLY UPDATES.//
NNNN

WDXS32 PGTW 120300
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 18S (EIGHTEEN) WARNING 
NR 004//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 13.4S 105.5E
   INITIAL INTENSITY: 35 KTS
   GEOGRAPHIC REFERENCE: 725 NM NORTHWEST OF LEARMONTH, AUSTRALIA
   MOVEMENT PAST 6 HOURS: SOUTHEASTWARD AT 17 KTS
   SIGNIFICANT WAVE HEIGHT: 20 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
CYCLONE (TC) 18S WITH AN EXPOSED LOW LEVEL CIRCULATION CENTER
(LLCC) WITH FLARING CONVECTION AND EXPANDING CIRRUS FILAMENTS TO
THE NORTHWEST OF THE LLCC AS THE SYSTEM EXPERIENCES STRONG VERTICAL
WIND SHEAR (VWS) FROM THE EAST. THE SYSTEM IS CURRENTLY TRACKING
SOUTHEASTWARD AS IT IS STEERED ON THE SOUTHERN PERIPHERY OF A NEAR
EQUATORIAL RIDGE (NER) TO THE NORTH. THE TRACK MOTION HOWEVER HAS
BEEN RATHER ERRATIC OVER THE PAST SIX HOURS, WITH THE LLCC DIVING
SOUTHEASTWARD UP TO THE 0000Z HOUR SUBSEQUENTLY STOMPING ON THE
BRAKES AND BECOMING ALMOST STATIONARY THROUGH THE 0200Z HOUR.
FAVORABLE SEA SURFACE TEMPERATURES AND FAVORABLE DIVERGENCE ALOFT
ENCOURAGING STRONG WESTWARD OUTFLOW ARE BEING OFFSET BY THE
ELEVATED VWS, INHIBITING DEVELOPMENT OF A CONSOLIDATED VORTEX. THE
INITIAL POSITION WAS ASSESSED WITH HIGH CONFIDENCE BASED ON THE
EXPOSED LLCC IN THE ANIMATED MSI. THE INITIAL INTENSITY WAS
ASSESSED WITH LOW CONFIDENCE DUE TO AN ABSENCE OF WIND SPEED
MEASUREMENTS, AS THUS BASED ENTIRELY ON AGENCY AND OBJECTIVE
ESTIMATES NOTED BELOW AS WELL AS THE OVERALL RAGGED AND
DETERIORATED STRUCTURE.

INITIAL WIND RADII BASIS: PERSISTENCE 

CURRENT STEERING MECHANISM: THE SOUTHERN PERIPHERY OF THE NER TO
THE NORTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   KNES: T1.5 - 25 KTS
   APRF: T1.5 - 25 KTS
   CIMSS SATCON: 45 KTS AT 122120Z
   CIMSS ADT: 33 KTS AT 120030Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 20-25 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: WEAK WESTWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: LOW
   INITIAL WIND RADII: LOW

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TC 18S WILL CONTINUE TO TRACK EAST-SOUTHEAST
FOR THE NEXT 72 HOURS WHILE UNDER THE INFLUENCE OF A NER TO THE
NORTH. THE SYSTEM WILL SLOW DOWN AFTER TAU 48 AS THE STEERING
GRADIENT WEAKENS AND THE SUBTROPICAL RIDGE (STR) CENTERED OVER
CENTRAL AUSTRALIA RIDGES WESTWARD, CREATING A COMPETING STEERING
PATTERN. BEYOND TAU 72, THE EVOLUTION OF THE STR PATTERN IS HIGHLY
UNCERTAIN, WITH THE ECMWF DEVELOPING A NORTH-SOUTH ORIENTED RIDGE,
WHILE IN THE GFS THE RIDGE REMAINS ORIENTED MORE EAST-WEST. THE
CURRENT FORECAST CALLS FOR THE SYSTEM TO RUN INTO THE NORTH-SOUTH
ORIENTED STR WHICH WILL BLOCK THE STORM FROM TRAVELING FURTHER EAST
AND WHICH WILL SLOW THE SPEED AND REDIRECT THE SYSTEM TO THE SOUTH
THROUGH THE END OF THE FORECAST PERIOD. TC 18S IS FORECAST TO
SLOWLY BUT STEADILY INTENSIFY OVER THE FIRST 72 HOURS OF THE FORECAST 
AS THE SYSTEM STRUGGLES TO CONSOLIDATE THE VORTEX AGAINST ELEVATED VWS 
OF 20-25KTS. AS VWS LESSENS FROM TAU 72-120, INTENSITY
IS EXPECTED TO INCREASE MORE RAPIDLY WITH FAVORABLE SEA SURFACE
TEMPERATURES OF 28-29C AND MOIST ENVIRONMENT, REACHING OF A PEAK OF
75 KNOTS BY TAU 120. 

MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN GOOD AGREEMENT
IN THE NEAR-TERM THAT THE STORM WILL TRACK TO THE EAST-SOUTHEAST
OVER THE NEXT 36 HOURS. HOWEVER, BY TAU 120 THE CROSS-TRACK SPREAD
OPENS TO 820NM, BOUNDED BY GALWEM TO THE SOUTHWEST AND GFS TO THE
NORTHEAST. THE VARIATIONS IN THE JTWC TRACK CONSENSUS MEMBERS CAN
BE EXPLAINED BY THE SIGNIFICANT DIFFERENCES IN THE STEERING
ENVIRONMENT REPRESENTED IN EACH MODEL. PARTICULARLY, ECMWF
REPRESENTS A MORE SOUTHERLY ROUTE CLOSER TO THE JTWC TRACK
CONSENSUS WHICH IS DRIVEN BY A LARGE STR OVER THE AUSTRALIAN
CONTINENT WHICH BLOCKS THE SYSTEM FROM CONTINUING ON ITS EASTWARD
TRACK AND CAUSES IT TO SLOWLY TURN TO THE SOUTHWEST. ON THE OTHER
HAND, GFS SHOWS THE RIDGE EXTENDING TOWARDS THE WEST OVER THE
FORECAST PERIOD, ALLOWING THE SYSTEM TO CONTINUE TO TRACK TO THE
NORTHWEST COAST OF AUSTRALIA BEFORE MARKING ITS TURN SOUTH BY TAU
72. DUE TO UNCERTAINTY IN DETERMINISTIC AND ENSEMBLE MODEL
GUIDANCE, THE TRACK FORECAST IS DETERMINED WITH LOW CONFIDENCE
THROUGH THE FORECAST PERIOD. THE JTWC INTENSITY CONSENSUS GUIDANCE
IS ALSO IN GOOD AGREEMENT THROUGH THE END OF THE FORECAST PERIOD
THAT THERE WILL BE A GRADUAL AND CONSISTENT INCREASE IN INTENSITY
WITH THE EXCEPTION OF COAMPS-TC (GFS VERSION) WHICH SPIKES TO
130KTS BETWEEN TAU 96-120 LIKELY DUE TO AN AMPLIFIED REACTION TO A
DROP IN VWS. HOWEVER, WHILE THE INTENSITY GUIDANCE ENVELOPE IS VERY
TIGHT, THE HIGH UNCERTAINTY IN THE TRACK LEADS TO LOW CONFIDENCE IN
THE INTENSITY, AS A TRACK FURTHER SOUTH WOULD LIKELY LEAD TO A MUCH
STRONGER SYSTEM VERSUS A MORE NORTHWARD TRACK. 

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: LOW
   TRACK 72-120 HR: LOW
   INTENSITY 0 - 72 HR: LOW
   INTENSITY 72-120 HR: LOW//
NNNN

ygsj24 楼主 W 2024-03-12 18:00:02

0 18楼

AXAU01 APRF 120841
IDW27600
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE
at: 0841 UTC 12/03/2024
Name: Tropical Low  
Identifier: 08U
Data At: 0600 UTC
Latitude: 13.5S
Longitude: 106.1E
Location Accuracy: within 25nm (45 km)
Movement Towards: east southeast (119 deg)
Speed of Movement: 9 knots (17 km/h)
Maximum 10-Minute Wind: 40 knots (75 km/h)
Maximum 3-Second Wind Gust: 55 knots (100 km/h)
Central Pressure: 998 hPa
Radius of 34-knot winds NE quadrant: 110 nm (205 km)
Radius of 34-knot winds SE quadrant: 
Radius of 34-knot winds SW quadrant: 
Radius of 34-knot winds NW quadrant: 140 nm (260 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:  nm ( km)
Radius of Maximum Winds:   nm (  km)
Dvorak Intensity Code: T1.5/2/0/S0.0/24HRS STT:S0.0/06HRS
Pressure of outermost isobar: 1004 hPa
Radius of outermost closed isobar: 150 nm (280 km)
FORECAST DATA
Date/Time    : Location    : Loc. Accuracy: Max Wind   : Central Pressure
(UTC)        : degrees     :      nm  (km): knots(km/h): hPa
+06:  12/1200: 13.9S 107.4E:     040 (080):  040  (075):  997
+12:  12/1800: 14.3S 108.8E:     055 (105):  040  (075):  996
+18:  13/0000: 14.7S 110.0E:     065 (120):  040  (075):  995
+24:  13/0600: 15.1S 111.1E:     075 (135):  040  (075):  995
+36:  13/1800: 15.8S 112.9E:     100 (180):  040  (075):  995
+48:  14/0600: 16.6S 113.9E:     130 (240):  040  (075):  992
+60:  14/1800: 17.4S 114.2E:     150 (280):  040  (075):  992
+72:  15/0600: 18.2S 114.0E:     175 (320):  045  (085):  990
+96:  16/0600: 19.4S 113.0E:     240 (440):  055  (100):  982
+120: 17/0600: 20.6S 111.9E:     320 (580):  060  (110):  980
REMARKS:
Deep convection remains confined well to the northwest of an exposed low level
circulation centre of Tropical Low 08U.  

Position is based on animated VIS imagery, persistence and recent microwave
passes. Confidence in the analysis position is good.  

Intensity is maintained at 40 knots based on earlier scatterometry passes,
though gales remain restricted to the northern quadrant. Dvorak analysis is
based on MET=1.0 on a S 24h trend. DT is inclusive as the LLCC is more than
90nm from deepest convection. CI is held at 2.0.  

08U is a shallow system that continues to track east with the low-level monsoon
flow and is limited by 22kt easterly shear. Environmental conditions are
otherwise favourable with SSTs 28-29C along track, decent monsoon flow to the
north and reasonable upper level divergence.  

08U is forecast to slowly become a deeper system during the week. Once this
happens, the influence of the mid-level ridge over Australia would then
increase and 08U is expected to turn towards the south. Gales are likely to
become more confined to the system centre and are forecast to extend into the
southern quadrants of 08U from Thursday. It is forecast to intensify into the
weekend as it tracks south under the influence of the ridge. 

The most likely track scenario keeps 08U off the coast of Western Australian as
it curves towards the southwest over the weekend. There is however a large
spread in the guidance in the longer term. A small number of guidance keeps the
system as a shallow low and track it further east, before developing it. If
this happens, then 08U is likely to be closer to the coast as it turns towards
the southwest over the weekend. In any case, there could be possible impacts
along the Pilbara coast due to its proximity to the coast.  

Copyright Commonwealth of Australia
==
The next bulletin for this system will be issued by: 12/1330 UTC.

	Time (AWST)	Intensity Category	Latitude (decimal deg.)	Longitude (decimal deg.)	Estimated Position Accuracy (km)
0hr	2 pm March 12	tropical low	13.5S	106.1E	45
+6hr	8 pm March 12	tropical low	13.9S	107.4E	80
+12hr	2 am March 13	tropical low	14.3S	108.8E	105
+18hr	8 am March 13	tropical low	14.7S	110.0E	120
+24hr	2 pm March 13	tropical low	15.1S	111.1E	135
+36hr	2 am March 14	tropical low	15.8S	112.9E	180
+48hr	2 pm March 14	tropical low	16.6S	113.9E	240
+60hr	2 am March 15	tropical low	17.4S	114.2E	280
+72hr	2 pm March 15	1	18.2S	114.0E	320

ygsj24 楼主 W 2024-03-12 18:00:02

0 19楼

WTXS32 PGTW 120900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 005//
RMKS/
1. TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 005    
   02 ACTIVE TROPICAL CYCLONES IN SOUTHIO
   MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE
   WIND RADII VALID OVER OPEN WATER ONLY
    ---
   WARNING POSITION:
   120600Z --- NEAR 13.4S 106.1E
     MOVEMENT PAST SIX HOURS - 090 DEGREES AT 06 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 - 100 NM NORTHEAST QUADRANT
                            080 NM SOUTHEAST QUADRANT
                            080 NM SOUTHWEST QUADRANT
                            200 NM NORTHWEST QUADRANT
   REPEAT POSIT: 13.4S 106.1E
    ---
   FORECASTS:
   12 HRS, VALID AT:
   121800Z --- 14.1S 108.7E
   MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT
                            050 NM SOUTHEAST QUADRANT
                            050 NM SOUTHWEST QUADRANT
                            150 NM NORTHWEST QUADRANT
   VECTOR TO 24 HR POSIT: 110 DEG/ 12 KTS
    ---
   24 HRS, VALID AT:
   130600Z --- 14.9S 111.0E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT
                            030 NM SOUTHEAST QUADRANT
                            070 NM SOUTHWEST QUADRANT
                            120 NM NORTHWEST QUADRANT
   VECTOR TO 36 HR POSIT: 110 DEG/ 09 KTS
    ---
   36 HRS, VALID AT:
   131800Z --- 15.5S 112.7E
   MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT
                            040 NM SOUTHEAST QUADRANT
                            080 NM SOUTHWEST QUADRANT
                            120 NM NORTHWEST QUADRANT
   VECTOR TO 48 HR POSIT: 120 DEG/ 07 KTS
    ---
   EXTENDED OUTLOOK:
   48 HRS, VALID AT:
   140600Z --- 16.2S 113.9E
   MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT
                            000 NM SOUTHEAST QUADRANT
                            000 NM SOUTHWEST QUADRANT
                            020 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT
                            050 NM SOUTHEAST QUADRANT
                            090 NM SOUTHWEST QUADRANT
                            140 NM NORTHWEST QUADRANT
   VECTOR TO 72 HR POSIT: 140 DEG/ 02 KTS
    ---
   72 HRS, VALID AT:
   150600Z --- 16.9S 114.5E
   MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT
                            000 NM SOUTHEAST QUADRANT
                            000 NM SOUTHWEST QUADRANT
                            020 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT
                            060 NM SOUTHEAST QUADRANT
                            100 NM SOUTHWEST QUADRANT
                            130 NM NORTHWEST QUADRANT
   VECTOR TO 96 HR POSIT: 175 DEG/ 03 KTS
    ---
   LONG RANGE OUTLOOK:
    ---
   96 HRS, VALID AT:
   160600Z --- 18.0S 114.6E
   MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT
                            020 NM SOUTHEAST QUADRANT
                            020 NM SOUTHWEST QUADRANT
                            030 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT
                            100 NM SOUTHEAST QUADRANT
                            110 NM SOUTHWEST QUADRANT
                            150 NM NORTHWEST QUADRANT
   VECTOR TO 120 HR POSIT: 195 DEG/ 03 KTS
    ---
   120 HRS, VALID AT:
   170600Z --- 19.2S 114.2E
   MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT
   WIND RADII VALID OVER OPEN WATER ONLY
   RADIUS OF 064 KT WINDS - 020 NM NORTHEAST QUADRANT
                            020 NM SOUTHEAST QUADRANT
                            020 NM SOUTHWEST QUADRANT
                            020 NM NORTHWEST QUADRANT
   RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT
                            050 NM SOUTHEAST QUADRANT
                            060 NM SOUTHWEST QUADRANT
                            060 NM NORTHWEST QUADRANT
   RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT
                            120 NM SOUTHEAST QUADRANT
                            120 NM SOUTHWEST QUADRANT
                            150 NM NORTHWEST QUADRANT
    ---
REMARKS:
120900Z POSITION NEAR 13.6S 106.7E.
12MAR24. TROPICAL CYCLONE 18S (EIGHTEEN), LOCATED APPROXIMATELY
702 NM NORTHWEST OF LEARMONTH, AUSTRALIA, HAS TRACKED EASTWARD AT
06 KNOTS OVER THE PAST SIX HOURS. MINIMUM CENTRAL PRESSURE AT
120600Z IS 999 MB. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 120600Z
IS 20 FEET.
NEXT WARNINGS AT 121500Z, 122100Z, 130300Z AND 130900Z.
REFER TO TROPICAL CYCLONE 17S (FILIPO) WARNINGS (WTXS31 PGTW)
FOR TWELVE-HOURLY UPDATES.//
NNNN

WDXS32 PGTW 120900
MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI//
SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 18S (EIGHTEEN)
WARNING NR 005//
RMKS/
1. FOR METEOROLOGISTS.
2. 6 HOUR SUMMARY AND ANALYSIS.

SUMMARY:
   INITIAL POSITION: 13.4S 106.1E
   INITIAL INTENSITY: 40 KTS
   GEOGRAPHIC REFERENCE: 702 NM NORTHWEST OF LEARMONTH, AUSTRALIA
   MOVEMENT PAST 6 HOURS: EASTWARD AT 06 KTS
   SIGNIFICANT WAVE HEIGHT: 20 FEET

SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION:
ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL
CYCLONE (TC) 18S (EIGHTEEN) WITH AN EXPOSED AND ELONGATED LOW-LEVEL
CIRCULATION CENTER (LLCC) HAVING DEEP CONVECTION DISPLACED TO THE
WEST-NORTHWEST OF THE CIRCULATION CENTER. A 120244Z ASCAT-C IMAGE
REVEALS THE ELONGATED NATURE OF THE CIRCULATION WITH 40 KTS WINDS IN
THE NORTHWESTERN QUADRANT. ENVIRONMENTAL ANALYSIS INDICATES THAT
18S IS IN A MARGINALLY FAVORABLE ENVIRONMENT FOR FURTHER
DEVELOPMENT WITH MODERATE OUTFLOW ALOFT, MODERATE TO HIGH (20-25 KTS)
VERTICAL WIND SHEAR, OFFSET BY WARM (28-29 C) SSTS. THE INITIAL 
POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE LLCC BEING 
EXPOSED AND EASILY IDENTIFIABLE IN ANIMATED IMAGERY AND A 120600Z 
HIMAWARI-9 VISIBLE SATELLITE IMAGE. THE INITIAL INTENSITY OF 40 KTS 
IS ASSESSED WITH HIGH CONFIDENCE BASED ON THE PREVIOUSLY MENTIONED 
ASCAT IMAGE.

INITIAL WIND RADII BASIS: SCATTEROMETER DATA 

CURRENT STEERING MECHANISM: SOUTHERN PERIPHERY OF A NEAR EQUATORIAL
RIDGE (NER) TO THE NORTH.

AGENCY DVORAK AND AUTOMATED FIXES: 
   PGTW: T2.0 - 30 KTS
   KNES: T1.5 - 25 KTS
   CIMSS SATCON: 43 KTS AT 120554Z
   CIMSS ADT: 33 KTS AT 120530Z

FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE
   VWS: 20-25 KTS
   SST: 29-30 CELSIUS
   OUTFLOW: MODERATE WESTWARD

ANALYSIS CONFIDENCE:
   INITIAL POSITION: HIGH
   INITIAL INTENSITY: HIGH
   INITIAL WIND RADII: HIGH

3. FORECAST REASONING.

SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO
THE FORECAST FROM THE PREVIOUS WARNING.

FORECAST DISCUSSION: TC 18S IS CURRENTLY TRACKING EASTWARD ALONG
THE SOUTHERN PERIPHERY OF A NER TO THE NORTH. AT TAU 48, TC 18S IS
FORECAST TO MAKE A POLEWARD TURN AS A RIDGE OVER WESTERN
AUSTRALIA BLOCKS THE SYSTEM FROM CONTINUING THE EASTWARD TRACK AND 
TURNS THE SYSTEM SOUTHWARD THROUGH TAU 72. AFTER TAU 72, TC 18S IS 
FORECAST TO CONTINUE TURNING TO A SOUTHWESTWARD TRACK BY TAU 120. THE
SYSTEM IS FORECASTED TO MAINTAIN A GRADUAL INTENSIFICATION TREND
THROUGHOUT THE FORECAST PERIOD DUE TO VWS VALUES BEGINNING TO
DECREASE BELOW 20 KTS AFTER TAU 12 AND UPPER-LEVEL DIVERGENCE
IMPROVING OUTFLOW ALOFT.

MODEL DISCUSSION: GLOBAL NUMERICAL MODEL GUIDANCE IS IN FAIR
AGREEMENT REGARDING TRACK AND GOOD AGREEMENT REGARDING INTENSITY. A
SIGNIFICANT CROSS-TRACK SPREAD OF APPROXIMATELY 503NM IS PRESENT BY
TAU 72, INDICATING MUCH UNCERTAINTY ON HOW FAR EAST THE SYSTEM
TRACKS BEFORE MAKING A TURN TO A SOUTHWESTWARD TRACK BY TAU 120. THE 
JTWC FORECAST TRACK ALIGNS CLOSELY WITH THE ECMWF DETERMINISTIC AND
ENSEMBLE GUIDANCE, WITH GFS THE FURTHEST EAST OF THE CONSENSUS
MEMBERS AND GALWEM THE FURTHEST WEST. INTENSITY GUIDANCE SUGGESTS
A GRADUAL RISE IN INTENSITY THROUGH TAU 120 AS THE ENVIRONMENT GROWS 
MORE FAVORABLE. WITH THE EXCEPTION OF COAMPS-TC, THE INTENSITY SPREAD 
IS GREATEST AMONG CONSENSUS MEMBERS NEAR TAU 96 WITH A 30 KTS SPREAD 
IN GUIDANCE.

FORECAST CONFIDENCE:
   TRACK 0 - 72 HR: MEDIUM
   TRACK 72-120 HR: LOW
   INTENSITY 0 - 72 HR: MEDIUM
   INTENSITY 72-120 HR: MEDIUM//
NNNN

ygsj24 楼主 W 2024-03-12 20:43:32

0 20楼

AXAU01 APRF 121259
IDW27600
TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION
Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE
at: 1259 UTC 12/03/2024
Name: Tropical Low  
Identifier: 08U
Data At: 1200 UTC
Latitude: 13.6S
Longitude: 107.2E
Location Accuracy: within 40nm (75 km)
Movement Towards: east (101 deg)
Speed of Movement: 8 knots (15 km/h)
Maximum 10-Minute Wind: 40 knots (75 km/h)
Maximum 3-Second Wind Gust: 55 knots (100 km/h)
Central Pressure: 995 hPa
Radius of 34-knot winds NE quadrant: 110 nm (205 km)
Radius of 34-knot winds SE quadrant: 
Radius of 34-knot winds SW quadrant: 
Radius of 34-knot winds NW quadrant: 140 nm (260 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:  nm ( km)
Radius of Maximum Winds:   nm (  km)
Dvorak Intensity Code: T2.0/2.0/D0.5/24HRS STT:D0.5/06HRS
Pressure of outermost isobar: 1004 hPa
Radius of outermost closed isobar: 180 nm (335 km)
FORECAST DATA
Date/Time    : Location    : Loc. Accuracy: Max Wind   : Central Pressure
(UTC)        : degrees     :      nm  (km): knots(km/h): hPa
+06:  12/1800: 13.9S 108.5E:     055 (100):  040  (075):  994
+12:  13/0000: 14.3S 109.9E:     060 (115):  040  (075):  994
+18:  13/0600: 14.8S 111.0E:     060 (110):  040  (075):  993
+24:  13/1200: 15.1S 112.1E:     065 (115):  040  (075):  993
+36:  14/0000: 15.6S 113.6E:     085 (160):  040  (075):  993
+48:  14/1200: 16.3S 114.7E:     125 (230):  040  (075):  992
+60:  15/0000: 16.9S 114.7E:     155 (290):  045  (085):  989
+72:  15/1200: 17.5S 114.4E:     180 (335):  050  (095):  986
+96:  16/1200: 18.2S 113.4E:     235 (435):  060  (110):  976
+120: 17/1200: 18.9S 112.3E:     310 (570):  055  (100):  981
REMARKS:
Deep convection remains confined mostly to the northwest of an exposed low
level circulation centre. Confidence in the analysis position is poor with the
exposed LLCC difficult to locate on overnight IR.

Intensity is maintained at 40 knots based on earlier ASCAT pass. Gales remain
restricted to the northern quadrant. DT is 3.0 using a shear pattern and the
centre less than 30nm from the strong T gradient. Given the low confidence in
the position, there is also low confidence in the DT. A lack of curvature in
the deep convection also makes curved band pattern difficult. MET is 2.5 based
on a standard development 24hr trend with deep convection increasing and moving
closer to the LLCC. PAT is 2.0 and given the low confidence in the DT, FT/CI
are also 2.0 based on PAT. Objective guidance: ADT 30kt, AiDT 30kt, DPRINT 30kt
(1-min average).

08U is a shallow system that continues to track east with the low-level monsoon
flow and is limited by easterly shear (CIMSS shear 27.5 kts). Environmental
conditions are otherwise favourable with SSTs 28-29C along track, strong
monsoon flow to the north and reasonable upper level divergence.

08U is forecast to slowly become a deeper system during the week. Once this
happens, the influence of a mid-level ridge over Australia will then increase
and 08U is expected to turn towards the south. Gales are likely to become more
confined to the system centre and are forecast to extend into the southern
quadrants of 08U from Thursday. It is forecast to intensify into the weekend as
it tracks south under the influence of the ridge.

The most likely track scenario is for 08U to remain off the coast as it curves
towards the southwest over the weekend. There is however a large spread in the
guidance over the weekend. A small number of guidance keeps the system as a
shallow low and tracks it further east, before developing. If this happens,
then 08U is likely to be closer to the coast as it turns towards the southwest.

Copyright Commonwealth of Australia
==
The next bulletin for this system will be issued by: 12/1930 UTC.

	Time (AWST)	Intensity Category	Latitude (decimal deg.)	Longitude (decimal deg.)	Estimated Position Accuracy (km)
0hr	8 pm March 12	tropical low	13.6S	107.2E	75
+6hr	2 am March 13	tropical low	13.9S	108.5E	100
+12hr	8 am March 13	tropical low	14.3S	109.9E	115
+18hr	2 pm March 13	tropical low	14.8S	111.0E	110
+24hr	8 pm March 13	tropical low	15.1S	112.1E	115
+36hr	8 am March 14	tropical low	15.6S	113.6E	160
+48hr	8 pm March 14	tropical low	16.3S	114.7E	230
+60hr	8 am March 15	1	16.9S	114.7E	290
+72hr	8 pm March 15	2	17.5S	114.4E	335

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