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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 -
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
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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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AXAU01 APRF 121839 IDW27600 TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE at: 1839 UTC 12/03/2024 Name: Tropical Low Identifier: 08U Data At: 1800 UTC Latitude: 13.9S Longitude: 108.8E Location Accuracy: within 40nm (75 km) Movement Towards: east (099 deg) Speed of Movement: 13 knots (25 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: 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:S0.0/06HRS Pressure of outermost isobar: 1006 hPa Radius of outermost closed isobar: 200 nm (370 km) FORECAST DATA Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure (UTC) : degrees : nm (km): knots(km/h): hPa +06: 13/0000: 14.3S 110.2E: 055 (100): 040 (075): 994 +12: 13/0600: 14.8S 111.3E: 065 (120): 040 (075): 993 +18: 13/1200: 15.1S 112.3E: 070 (130): 040 (075): 993 +24: 13/1800: 15.4S 113.1E: 075 (140): 040 (075): 993 +36: 14/0600: 16.0S 114.4E: 095 (175): 040 (075): 993 +48: 14/1800: 16.7S 115.0E: 125 (230): 040 (075): 992 +60: 15/0600: 17.4S 114.8E: 155 (290): 045 (085): 990 +72: 15/1800: 17.7S 114.4E: 170 (315): 050 (095): 986 +96: 16/1800: 18.3S 113.3E: 225 (420): 060 (110): 977 +120: 17/1800: 19.1S 112.2E: 280 (515): 055 (100): 981 REMARKS: Tropical low 08U remains under the influence of strong deep layer easterly wind shear. There has been little change in the satellite presentation compared with 24 hours ago, with deep convection displaced to the west of the estimated low level centre and showing little curvature or rotation. Confidence in the centre position is low. Dvorak analysis: low confidence in shear pattern DT given low confidence in centre position. Weak 0.3 to 0.4 wrap curved band is likewise dubious. MET is 2.0 based on a 24 hour S trend with no PAT adjustment. Final T 2.0 with CI also 2.0, below the analysed intensity. Objective guidance: ADT 33kt, AiDT 32kt, DPRINT 29kt, DMINT 30kt, SATCON 44kt (1-min average). Intensity maintained at 40 knots based chiefly on persistence from the Tuesday morning ASCAT pass given the static nature of the cloud pattern. Gales remain confined to northern quadrants only, supported by partial scatterometry passes during the past 12 to 18 hours. 08U is currently tracking east with the low-level monsoon flow, with development constrained by strong easterly shear (analysed by CIMSS winds at approximately 30 knots). Environmental conditions are otherwise favourable with SSTs 28-29C along track, strong monsoon flow to the north, reasonable upper level divergence, and upper level winds supportive of poleward outflow as the system deepens. 08U is forecast to slowly become a deeper system during the week. Once this happens, the influence of a mid-level ridge to the south will increase and slow the system down. At the same time, an amplifying upper level trough to the west will steer the system slowly to the south. The resulting reduction in deep layer wind shear should allow the system to develop and become more symmetric late in the week. It is forecast to intensify into the weekend as it tracks south and then southwest 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. Another scenario is that the system remains a shallow low for longer and tracks 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: 13/0130 UTC.
Time (AWST) Intensity Category Latitude
(decimal deg.)Longitude
(decimal deg.)Estimated Position
Accuracy (km)0hr 2 am March 13 tropical low 13.9S 108.8E 75 +6hr 8 am March 13 tropical low 14.3S 110.2E 100 +12hr 2 pm March 13 tropical low 14.8S 111.3E 120 +18hr 8 pm March 13 tropical low 15.1S 112.3E 130 +24hr 2 am March 14 tropical low 15.4S 113.1E 140 +36hr 2 pm March 14 tropical low 16.0S 114.4E 175 +48hr 2 am March 15 tropical low 16.7S 115.0E 230 +60hr 2 pm March 15 1 17.4S 114.8E 290 +72hr 2 am March 16 2 17.7S 114.4E 315 -
WTXS32 PGTW 122100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 007// RMKS/ 1. TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 007 02 ACTIVE TROPICAL CYCLONES IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 121800Z --- NEAR 14.0S 109.4E MOVEMENT PAST SIX HOURS - 120 DEGREES AT 19 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 130 NM NORTHWEST QUADRANT REPEAT POSIT: 14.0S 109.4E --- FORECASTS: 12 HRS, VALID AT: 130600Z --- 14.8S 111.9E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 120 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 105 DEG/ 10 KTS --- 24 HRS, VALID AT: 131800Z --- 15.3S 114.0E 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 040 NM SOUTHWEST QUADRANT 110 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 120 DEG/ 07 KTS --- 36 HRS, VALID AT: 140600Z --- 15.9S 115.2E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT 100 NM SOUTHEAST QUADRANT 080 NM SOUTHWEST QUADRANT 110 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 135 DEG/ 04 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 141800Z --- 16.5S 115.8E 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 000 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT 120 NM SOUTHEAST QUADRANT 100 NM SOUTHWEST QUADRANT 100 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 180 DEG/ 02 KTS --- 72 HRS, VALID AT: 151800Z --- 17.4S 115.8E MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 130 NM NORTHEAST QUADRANT 130 NM SOUTHEAST QUADRANT 130 NM SOUTHWEST QUADRANT 100 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 210 DEG/ 03 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 161800Z --- 18.3S 115.3E MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 030 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 070 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 140 NM NORTHEAST QUADRANT 150 NM SOUTHEAST QUADRANT 140 NM SOUTHWEST QUADRANT 110 NM NORTHWEST QUADRANT VECTOR TO 120 HR POSIT: 225 DEG/ 03 KTS --- 120 HRS, VALID AT: 171800Z --- 19.0S 114.5E MAX SUSTAINED WINDS - 080 KT, GUSTS 100 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 035 NM NORTHEAST QUADRANT 035 NM SOUTHEAST QUADRANT 035 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 - 150 NM NORTHEAST QUADRANT 160 NM SOUTHEAST QUADRANT 150 NM SOUTHWEST QUADRANT 130 NM NORTHWEST QUADRANT --- REMARKS: 122100Z POSITION NEAR 14.2S 110.0E. 12MAR24. TROPICAL CYCLONE 18S (EIGHTEEN), LOCATED APPROXIMATELY 565 NM NORTH-NORTHWEST OF LEARMONTH, AUSTRALIA, HAS TRACKED EAST- sOUTHEASTWARD AT 19 KNOTS OVER THE PAST SIX HOURS. MNIMUM CENTRAL PRESSURE AT 121800Z IS 999 MB. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 121800Z IS 20 FEET. NEXT WARNINGS AT 130300Z, 130900Z, 131500Z AND 132100Z. REFER TO TROPICAL CYCLONE 17S (FILIPO) WARNINGS (WTXS31 PGTW) FOR TWELVE-HOURLY UPDATES. // NNNN
WDXS32 PGTW 122100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 007// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 14.0S 109.4E INITIAL INTENSITY: 40 KTS GEOGRAPHIC REFERENCE: 565 NM NORTH-NORTHWEST OF LEARMONTH, AUSTRALIA MOVEMENT PAST 6 HOURS: EAST-SOUTHEASTWARD AT 19 KTS SIGNIFICANT WAVE HEIGHT: 20 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS TROPICAL CYCLONE (TC) 18S WITH A PARTIALLY OBSCURED LOW-LEVEL CIRCULATION CENTER (LLCC) AND DEEP CONVECTION FLARING TO THE WEST. A 121807Z AMSR2 COLOR-ENHANCED 89GHZ MICROWAVE IMAGE DEPICTS VERY BROAD SPIRAL BANDS WRAPPING INTO A DEFINED AND FULLY EXPOSED LLCC TO THE EAST OF A PATCH OF DISORGANIZED CONVECTION. CIRRUS FILAMENTS EXPAND FROM THE CONVECTION CENTER PRIMARILY TOWARDS THE WEST, AS THE UPPER-LEVEL VORTEX STRUGGLES TO OVERCOME THE INFLUENCE OF THE STRONG 30KT EASTERLY VERTICAL WIND SHEAR (VWS). ALSO RESULTING FROM VWS, WEAK WESTWARD OUTFLOW IS BLOWN OF THE LLCC, WHICH IS EXHIBITING SIGNIFICANT VERTICAL TILT WITH HEIGHT. DESPITE THE UNFAVORABLE ELEMENTS, SEA SURFACE TEMPERATURES AND STRONG WESTERLIES TO THE NORTH OF THE STORM ENHANCING VORTICITY WHICH SHOULD HELP TO STEADY IMPROVE THE VORTEX STRUCTURE OVER THE NEXT 24 HOURS. THE STEERING ENVIRONMENT IS PRIMARILY DRIVING THE SYSTEM TO THE EAST-SOUTHEAST ON THE SOUTHERN PERIPHERY OF A STRONG NEAR EQUATORIAL RIDGE (NER) TO THE NORTH. THE INITIAL POSITION WAS ASSESSED WITH HIGH CONFIDENCE BASED ON ANIMATED EIR REVEALING THE PARTIALLY OBSCURED LLCC. THE INITIAL INTENSITY WAS ASSESSED WITH LOW CONFIDENCE BASED ON AGENCY AND OBJECTIVE FIXES LISTED BELOW. SATCON ASSESSES THE SYSTEM AS 44 KTS, HOWEVER IT IS SUSPECTED THAT THE WIND FIELD IS SIGNIFICANTLY WEAKER IN THE SOUTHERN HEMISPHERE OF THE SYSTEM, BASED ON ANALYSIS OF EARLIER SCATTEROMETER DATA WHICH SHOWED WINDS AT OR BELOW 25 KTS. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: THE SOUTHERN PERIPHERY OF A NEAR EQUATORIAL RIDGE TO THE NORTH. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T2.0 - 30 KTS KNES: T2.0 - 30 KTS APRF: T2.0 - 30 KTS CIMSS SATCON: 44 KTS AT 121630Z CIMSS ADT: 33 KTS AT 121730Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE 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 CONTINUE TO TRACK EAST-SOUTHEAST ON THE SOUTHERN PERIPHERY OF AN NER TO THE NORTH OVER THE NEXT 48 HOURS BEFORE SLOWING TRACK SPEED AND CURVING TO THE SOUTH UNTIL TAU 72. A SUBTROPICAL RIDGE (STR) EXPANDING OVER THE AUSTRALIAN CONTINENT IS ANTICIPATED TO REDIRECT THE SYSTEM TO THE SOUTHWEST THROUGH THE END OF THE FORECAST PERIOD. THE FORECAST TRACK REMAINS UNCERTAIN, ESPECIALLY AFTER TAU 72, DUE TO MODERATE DISAGREEMENT IN HOW STRONGLY THE RIDGE WILL INFLUENCE THE SYSTEM AND WHETHER IT WILL HAVE A NORTH-SOUTH ALIGNMENT FORCING THE SYSTEM TO TRACK FARTHER SOUTH OR WILL HAVE AN EAST-WEST ALIGNMENT ALLOWING THE STORM TO TRACK FARTHER EAST AND IMPACT THE NORTHWESTERN COAST OF AUSTRALIA. LITTLE IN THE WAY OF INTENSIFICATION IS EXPECTED THROUGH THE FIRST 24 HOURS OF THE FORECAST AS MODERATE TO HIGH SHEAR WILL CONTINUE TO IMPACT THE SYSTEM. SHEAR BEGINS TO DROP OFF WHICH WILL ALLOW FOR A MORE RAPID PACE OF INTENSIFICATION, TO A PEAK OF 80KTS AT THE END OF THE FORECAST PERIOD. MODEL DISCUSSION: THE JTWC CONSENSUS TRACK GUIDANCE HAS IMPROVED OVER THE LAST 12 HOURS, HOWEVER THE CROSS-TRACK SPREAD IS STILL LARGE AT 450NM BY TAU 120. THE TRACK DIRECTION HAS ALSO OVERALL TAKEN A MORE SOUTHERLY TURN SHOWING MORE AGREEMENT IN THE NORTH-SOUTH ORIENTATION OF THE STR OVER AUSTRALIA, DESPITE GFS BOUNDING THE SPREAD TO THE EAST AND GALWEM BOUNDING THE TRACK TO THE WEST. THE JTWC FORECAST TRACK GENERALLY CONFORMS TO THE ECMWF TRACK AND THE CONSENSUS MEAN, FASTER THAN THE GFS BUT SLOWER THAN THE UKMET AND GALWEM. DUE THE LARGE SPREAD IN THE DETERMINISTIC AND ENSEMBLE GUIDANCE, THERE IS LOW CONFIDENCE IN THE JTWC FORECAST TRACK. INTENSITY GUIDANCE IS ALSO IN GOOD AGREEMENT THROUGH TAU 84, WITH THE EXCEPTION OF COAMPS-TC SPIKING AT TAU 60 AND INTENSIFYING TO 110KTS BY TAU 96 BEFORE DROPPING OFF AT THE END OF THE FORECAST. ADDITIONALLY, THE HAFS-A GUIDANCE SUGGESTS A PEAK INTENSITY ABOVE 110 KNOTS, AND THE COAMPS-TC ENSEMBLE INTENSITY PROBABILITIES SHOW A LOW (30 PERCENT) CHANCE OF RAPID INTENSIFICATION AFTER TAU 96. THE INTENSITY FORECAST IS ASSESSED WITH LOW CONFIDENCE ON THE BASIS THAT TRACK DEVIATIONS CAN CAUSE SIGNIFICANTLY DIFFERENT RESULTS IN INTENSITY AND THE RELATIVELY LARGE SPREAD IN THE INTENSITY GUIDANCE. 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 2024-03-13 18:00:02 被ygsj24编辑 ，原因： -
AXAU01 APRF 130107 IDW27600 TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE at: 0107 UTC 13/03/2024 Name: Tropical Low Identifier: 08U Data At: 0000 UTC Latitude: 14.6S Longitude: 110.4E Location Accuracy: within 30nm (55 km) Movement Towards: east southeast (108 deg) Speed of Movement: 16 knots (30 km/h) Maximum 10-Minute Wind: 35 knots (65 km/h) Maximum 3-Second Wind Gust: 50 knots (95 km/h) Central Pressure: 997 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: 110 nm (205 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:W0.5/06HRS Pressure of outermost isobar: 1004 hPa Radius of outermost closed isobar: 170 nm (315 km) FORECAST DATA Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure (UTC) : degrees : nm (km): knots(km/h): hPa +06: 13/0600: 15.1S 111.6E: 045 (085): 035 (065): 996 +12: 13/1200: 15.3S 112.7E: 055 (105): 035 (065): 996 +18: 13/1800: 15.4S 113.6E: 065 (120): 035 (065): 995 +24: 14/0000: 15.5S 114.5E: 075 (140): 035 (065): 996 +36: 14/1200: 16.1S 116.0E: 095 (170): 035 (065): 995 +48: 15/0000: 16.8S 116.5E: 120 (225): 040 (075): 993 +60: 15/1200: 17.2S 116.1E: 145 (270): 045 (085): 989 +72: 16/0000: 17.5S 115.5E: 165 (305): 055 (100): 983 +96: 17/0000: 17.9S 114.6E: 205 (375): 060 (110): 979 +120: 18/0000: 19.0S 113.5E: 270 (500): 060 (110): 977 REMARKS: Tropical low 08U remains under the influence of strong deep layer easterly wind shear. Recent visible imagery indicates a twin low level centre with deep convection displaced more than 100 n mi to the west. This represents a slight weakening trend over the past 24 hours. Confidence in the centre position is low. Dvorak analysis: DT 1.5 +- 0.5 from shear pattern. MET of 1.0 based on a W- trend, no PAT adjustment. FT of 1.5 due to constraints and CI of 2.0. Objective guidance: ADT 33kt, AiDT 33kt, DPRINT 28kt, DMINT 26kt, SATCON 44kt (1-min average). Intensity lowered to 35 knots based chiefly on persistence from the Tuesday morning ASCAT, AMSR2 scat winds and the slight weakening in the cloud pattern. Gales remain confined to northern quadrants only, supported by partial scatterometry passes during the past 12 to 18 hours. 08U is currently tracking east with the low-level monsoon flow, with development constrained by strong easterly shear (analysed by CIMSS winds at approximately 30 knots). Environmental conditions are otherwise favourable with SSTs 28-29C along track, strong monsoon flow to the north, reasonable upper level divergence, and upper level winds supportive of poleward outflow as the system deepens. 08U is forecast to slowly become a deeper system during the week. Once this happens, the influence of a mid-level ridge to the south will increase and slow the system down. At the same time, an amplifying upper level trough to the west will steer the system slowly to the south. The resulting reduction in deep layer wind shear should allow the system to develop and become more symmetric later in the week. It is forecast to intensify into the weekend as it tracks south and then southwest 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. Another scenario is that the system remains a shallow low for longer and tracks further east before developing. If this happens, then 08U is likely to be further east when it turns to the southwest increasing the chance of reaching the west Pilbara coast. Copyright Commonwealth of Australia == The next bulletin for this system will be issued by: 13/0730 UTC.
Time (AWST) Intensity Category Latitude
(decimal deg.)Longitude
(decimal deg.)Estimated Position
Accuracy (km)0hr 8 am March 13 tropical low 14.6S 110.4E 55 +6hr 2 pm March 13 tropical low 15.1S 111.6E 85 +12hr 8 pm March 13 tropical low 15.3S 112.7E 105 +18hr 2 am March 14 tropical low 15.4S 113.6E 120 +24hr 8 am March 14 tropical low 15.5S 114.5E 140 +36hr 8 pm March 14 tropical low 16.1S 116.0E 170 +48hr 8 am March 15 1 16.8S 116.5E 225 +60hr 8 pm March 15 1 17.2S 116.1E 270 +72hr 8 am March 16 2 17.5S 115.5E 305 -
WTXS32 PGTW 130300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 008// RMKS/ 1. TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 008 02 ACTIVE TROPICAL CYCLONES IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 130000Z --- NEAR 14.5S 110.2E MOVEMENT PAST SIX HOURS - 125 DEGREES AT 13 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 - 080 NM NORTHEAST QUADRANT 000 NM SOUTHEAST QUADRANT 000 NM SOUTHWEST QUADRANT 120 NM NORTHWEST QUADRANT REPEAT POSIT: 14.5S 110.2E --- FORECASTS: 12 HRS, VALID AT: 131200Z --- 15.2S 112.5E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 000 NM SOUTHWEST QUADRANT 140 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 105 DEG/ 09 KTS --- 24 HRS, VALID AT: 140000Z --- 15.6S 114.4E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 100 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 000 NM SOUTHWEST QUADRANT 120 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 115 DEG/ 07 KTS --- 36 HRS, VALID AT: 141200Z --- 16.2S 115.7E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 110 NM NORTHEAST QUADRANT 100 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 120 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 130 DEG/ 05 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 150000Z --- 16.8S 116.5E MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 000 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 120 NM NORTHEAST QUADRANT 120 NM SOUTHEAST QUADRANT 080 NM SOUTHWEST QUADRANT 110 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 180 DEG/ 03 KTS --- 72 HRS, VALID AT: 160000Z --- 17.9S 116.5E MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 130 NM NORTHEAST QUADRANT 130 NM SOUTHEAST QUADRANT 120 NM SOUTHWEST QUADRANT 100 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 210 DEG/ 02 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 170000Z --- 18.6S 116.1E MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 030 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 060 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 130 NM NORTHEAST QUADRANT 150 NM SOUTHEAST QUADRANT 140 NM SOUTHWEST QUADRANT 110 NM NORTHWEST QUADRANT VECTOR TO 120 HR POSIT: 220 DEG/ 02 KTS --- 120 HRS, VALID AT: 180000Z --- 19.3S 115.5E MAX SUSTAINED WINDS - 080 KT, GUSTS 100 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 035 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 035 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 - 150 NM NORTHEAST QUADRANT 160 NM SOUTHEAST QUADRANT 150 NM SOUTHWEST QUADRANT 130 NM NORTHWEST QUADRANT --- REMARKS: 130300Z POSITION NEAR 14.7S 110.8E. 13MAR24. TROPICAL CYCLONE 18S (EIGHTEEN), LOCATED APPROXIMATELY 518 NM NORTH-NORTHWEST OF LEARMONTH, AUSTRALIA, HAS TRACKED SOUTHEASTWARD AT 13 KNOTS OVER THE PAST SIX HOURS. MINIMUM CENTRAL PRESSURE AT 130000Z IS 999 MB. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 130000Z IS 18 FEET. NEXT WARNINGS AT 131500Z AND 140300Z. REFER TO TROPICAL CYCLONE 17S (FILIPO) WARNINGS (WTXS31 PGTW) FOR TWELVE-HOURLY UPDATES. // NNNN
WDXS32 PGTW 130300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 008// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 14.5S 110.2E INITIAL INTENSITY: 35 KTS GEOGRAPHIC REFERENCE: 518 NM NORTH-NORTHWEST OF LEARMONTH, AUSTRALIA MOVEMENT PAST 6 HOURS: SOUTHEASTWARD AT 13 KTS SIGNIFICANT WAVE HEIGHT: 18 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A HIGHLY IRREGULAR TROPICAL CYCLONE, WITH TWO DISTINCT LOWER-LEVEL CIRCULATION CENTERS (LLCC), ONE TO THE NORTHWEST AND TRAVELLING EASTWARD FASTER THAN THE SECOND CIRCULATION TO THE SOUTHEAST WHICH APPEARS TO HAVE BECOME STATIONARY. THE TWO CENTERS ARE CURRENTLY ASSESSED AS UNDERGOING A FUJIWHARA INTERACTION. STRONG 30KT VERTICAL WIND SHEAR (VWS) FROM THE EAST IS BLOWING THE DEEP LAYER CONVECTION COMPLETELY OFF OF THE VORTICES LEAVING BOTH CIRCULATIONS FULLY EXPOSED, DESPITE A FAVORABLY MOIST ENVIRONMENT AND WARM SEA SURFACE TEMPERATURES (SST). THE POSITION WAS ASSESSED WITH MEDIUM CONFIDENCE GIVEN THAT THE POSITION WAS PLACED IN THE CENTROID BETWEEN THE TWO CIRCULATIONS DEFINED ABOVE. THE INTENSITY WAS ASSESSED WITH MEDIUM CONFIDENCE, AT A GENEROUS 35KTS, BASED ON AN 121800Z AMSR2 WINDSPEED PRODUCT SHOWING A BAND OF ELEVATED WIND SPEEDS NORTH OF THE CIRCULATION. SUBJECTIVE AND OBJECTIVE INTENSITY ESTIMATES ARE FOR THE MOST PART MUCH LOWER THAN THE AMSR2 MEASUREMENT. INITIAL WIND RADII BASIS: OTHER (AMSR2 WINDSPEED PRODUCT). 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: T2.0 - 30 KTS APRF: T1.5 - 25 KTS CIMSS ADT: 32 KTS AT 120030Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL VWS: 15-20 KTS SST: 29-30 CELSIUS OUTFLOW: WEAK WESTWARD ANALYSIS CONFIDENCE: INITIAL POSITION: MEDIUM INITIAL INTENSITY: MEDIUM INITIAL WIND RADII: MEDIUM 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 CONTINUE TRACKING EAST-SOUTHEAST ON THE SOUTHERN PERIPHERY OF AN NER TO THE NORTH FOR THE NEXT 36 HOURS. INTERACTION WITH A SUBTROPICAL RIDGE (STR) OVER THE CONTINENT OF AUSTRALIA IS EXPECTED TO SLOW THE SYSTEM AND REDIRECT THE CYCLONE TO THE SOUTHWEST AT APPROXIMATELY TAU 72 AND CONTINUING ON THAT TRACK THROUGH THE END OF THE FORECAST PERIOD. THE FORECAST TRACK REMAINS UNCERTAIN, ESPECIALLY AFTER TAU 72, DUE TO MODERATE DISAGREEMENT IN HOW STRONGLY THE STR WILL INFLUENCE THE SYSTEM AND WHETHER IT WILL HAVE A NORTH-SOUTH ALIGNMENT FORCING THE SYSTEM TO TRACK FARTHER SOUTH OR WILL HAVE AN EAST-WEST ALIGNMENT ALLOWING THE STORM TO TRACK FARTHER EAST AND APPROACH THE NORTHWESTERN COAST OF AUSTRALIA. IN THE NEAR-TERM, THE LACK OF AN ORGANIZED, SINGULAR VORTEX, COMBINED WITH THE STRONG EASTERLY SHEAR, WILL RESULT IN LITTLE TO NO INTENSIFICATION THROUGH TAU 24. THE LATEST SHIPS OUTPUT CONTINUES TO INSIST THAT SHEAR WILL DECREASE AFTER TAU 36, WHICH WILL ALLOW THE VORTEX TO FINALLY CONSOLIDATE AND THE SYSTEM TO STEADILY INCREASE IN INTENSITY TO A FORECASTED PEAK OF 80 KNOTS BY THE END OF THE FORECAST PERIOD. MODEL DISCUSSION: THE JTWC CONSENSUS TRACK GUIDANCE HAS OPENED OVER THE LAST SIX HOURS TO A CROSS-TRACK ERROR OF 550NM BY TAU 120, BANDED BY GALWEM TO THE WEST AND GFS TO THE EAST. GFS ANTICIPATES THE SYSTEM WILL CONTINUE NEARLY DUE EAST BEFORE SHARPLY TURNING TO THE SOUTHWEST AT TAU 72. ECMWF AND UKMET BOTH INITIALLY TRACK TO THE EAST-SOUTHEAST, AND SLOWLY CURVE TO THE SOUTHWEST BETWEEN TAU 48 AND TAU 72. THE LARGE SPREAD IN THE DETERMINISTIC AND ENSEMBLE GUIDANCE RESULTS IN LOW CONFIDENCE IN THE JTWC FORECAST, WHICH CONFORMS CLOSELY TO THE ECMWF AND THE CONSENSUS MEAN. INTENSITY GUIDANCE IS IN GOOD AGREEMENT IN TERMS OF THE GRADUAL INCREASE TO 80KTS BY TAU 120, HOWEVER BOTH COAMPS-TC (GFS-BASED) AND COAMPS-TC (NAVGEM-BASED) HAVE SIGNIFICANTLY HIGHER PEAKS UP TO 100KTS. ADDITIONALLY, THE COAMPS-TC ENSEMBLE INTENSITY PROBABILITY PRODUCT SHOWS INCREASING CHANCES OF RAPID INTENSIFICATION AFTER TAU 96 (NOW UP TO 40 PERCENT PROBABILITY), WHILE THE SAME PRODUCT BASED ON GEFS SHOWS A LOW, BUT INCREASING CHANCE AS WELL. AS A RESULT, THE CHANCE OF A PERIOD OF RI AT THE END OF THE FORECAST PERIOD CANNOT BE RULED OUT. FORECAST CONFIDENCE: TRACK 0 - 72 HR: LOW TRACK 72-120 HR: LOW INTENSITY 0 - 72 HR: LOW INTENSITY 72-120 HR: LOW// NNNN
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AXAU01 APRF 130717 IDW27600 TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE at: 0717 UTC 13/03/2024 Name: Tropical Low Identifier: 08U Data At: 0600 UTC Latitude: 15.2S Longitude: 111.2E Location Accuracy: within 40nm (75 km) Movement Towards: east southeast (119 deg) Speed of Movement: 13 knots (25 km/h) Maximum 10-Minute Wind: 35 knots (65 km/h) Maximum 3-Second Wind Gust: 50 knots (95 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: 110 nm (205 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: T1.0/1.5/W1.0/24HRS STT:W0.5/06HRS Pressure of outermost isobar: 1002 hPa Radius of outermost closed isobar: 120 nm (220 km) FORECAST DATA Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure (UTC) : degrees : nm (km): knots(km/h): hPa +06: 13/1200: 15.5S 112.4E: 055 (100): 035 (065): 994 +12: 13/1800: 15.7S 113.3E: 065 (120): 035 (065): 994 +18: 14/0000: 15.8S 114.2E: 075 (140): 035 (065): 994 +24: 14/0600: 16.1S 114.8E: 085 (160): 035 (065): 994 +36: 14/1800: 16.6S 115.7E: 110 (205): 035 (065): 993 +48: 15/0600: 17.3S 115.8E: 135 (255): 035 (065): 993 +60: 15/1800: 17.5S 115.3E: 150 (275): 035 (065): 993 +72: 16/0600: 17.9S 114.8E: 170 (315): 040 (075): 991 +96: 17/0600: 18.5S 114.1E: 220 (405): 050 (095): 983 +120: 18/0600: 20.2S 113.4E: 285 (530): 060 (110): 975 REMARKS: Tropical low 08U remains under the influence of strong deep layer easterly wind shear. Recent visible imagery indicates a twin low level centre with deep convection displaced more than 100 n mi to the west, but with the second centre now dissipating. This represents a slight weakening trend over the past 24 hours. Confidence in the centre position is low. Dvorak analysis: No reliable cloud pattern. MET of 1.0 based on a W- trend, no PAT adjustment. FT of 1.0, CI of 2.0. Objective guidance: ADT 28kt, AiDT 31kt, DPRINT 27kt, DMINT 26kt (old), SATCON 44kt (old) (1-min average). Recent scatterometry indicates about 30 knots to the north, but re-strengthening to gales is the short term in the strong monsoonal flow to the north is likely. Gales analysed and forecast to persist in the northern quadrants. 08U is currently tracking east with the low-level monsoon flow, with development constrained by strong easterly shear (analysed by CIMSS winds at approximately 30 knots). Environmental conditions are otherwise somewhat favourable with SSTs 28-29C along track and strong monsoon flow to the north. Shear is expected to ease and become more northerly by the weekend, and upper level winds are forecast to become supportive of poleward outflow. 08U is forecast to slowly become a deeper system during the week. Once this happens, the influence of a mid-level ridge to the south will increase and slow the system down. At the same time, an amplifying upper level trough to the west will steer the system slowly to the south. The resulting reduction in deep layer wind shear should allow the system to develop and become more symmetric later in the week. It is forecast to intensify over the weekend and early next week as it tracks south and then southwest 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. There is the possibility of it moving further east before turning to the south then southwest, which would see it move closer to or across the west Pilbara coast. Copyright Commonwealth of Australia == The next bulletin for this system will be issued by: 13/1330 UTC.
Time (AWST) Intensity Category Latitude
(decimal deg.)Longitude
(decimal deg.)Estimated Position
Accuracy (km)0hr 2 pm March 13 tropical low 15.2S 111.2E 75 +6hr 8 pm March 13 tropical low 15.5S 112.4E 100 +12hr 2 am March 14 tropical low 15.7S 113.3E 120 +18hr 8 am March 14 tropical low 15.8S 114.2E 140 +24hr 2 pm March 14 tropical low 16.1S 114.8E 160 +36hr 2 am March 15 tropical low 16.6S 115.7E 205 +48hr 2 pm March 15 tropical low 17.3S 115.8E 255 +60hr 2 am March 16 tropical low 17.5S 115.3E 275 +72hr 2 pm March 16 1 17.9S 114.8E 315