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AXAU01 APRF 141321 IDW27600 TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE at: 1321 UTC 14/03/2024 Name: Tropical Low Identifier: 08U Data At: 1200 UTC Latitude: 16.9S Longitude: 115.4E Location Accuracy: within 40nm (75 km) Movement Towards: southeast (129 deg) Speed of Movement: 12 knots (22 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: 100 nm (185 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: T1.5/1.5/D0.5/24HRS STT:S0.0/06HRS Pressure of outermost isobar: 1002 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: 14/1800: 17.2S 115.6E: 055 (100): 035 (065): 993 +12: 15/0000: 17.4S 115.7E: 065 (125): 035 (065): 993 +18: 15/0600: 17.6S 115.7E: 075 (135): 035 (065): 992 +24: 15/1200: 17.8S 115.6E: 080 (145): 030 (055): 994 +36: 16/0000: 17.9S 115.1E: 090 (165): 030 (055): 996 +48: 16/1200: 18.1S 114.6E: 110 (205): 030 (055): 996 +60: 17/0000: 18.3S 114.1E: 135 (255): 040 (075): 989 +72: 17/1200: 18.8S 113.8E: 155 (285): 045 (085): 983 +96: 18/1200: 20.0S 113.1E: 200 (370): 060 (110): 976 +120: 19/1200: 21.2S 112.1E: 275 (505): 040 (075): 989 REMARKS: Strong easterly wind shear continues to influence 08U with the low level circulation exposed. Convection has mostly been displaced to the west however in the last three hours there has been a small area of deep convection develop on the up-shear side to the east of the LLCC. Position is based on animated IR imagery, with low confidence. Dvorak analysis: Shear pattern gives DT 2.0 with the estimated centre displaced approximately 0.75 degrees from the deep convection. This is based on the more persistent convection to the west rather than the area that has recently developed to the east. Given the low confidence in the position, there is also low confidence in the DT. MET is 1.5 based on a 24 hour D- trend, and PT agrees. FT of 1.5 based on MET/PAT. Given FT has plateaued for greater than 6 hours, CI is now also 1.5 . Objective guidance: ADT 29kn, AiDT 31kn and DPRINT 26kn (all 1-min average). Intensity has been maintained at 35kn based on earlier ASCAT passes. 08U has been moving more to the southeast in the last six hours as the influence of the low level monsoon flow begins to ease. Development continues to be 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. Shear is expected to ease and become more northerly by the weekend, and upper level winds are forecast to become supportive of poleward outflow. The influence of a mid-level ridge to the south will slow the system down before an amplifying upper level trough to the west will begin to steer the system slowly to the south. The resulting reduction in deep layer wind shear should allow the system to begin to develop, and tropical cyclone strength is currently forecast from Sunday. Further intensification is possible as 08U tracks south and then southwest under the influence of the ridge over the weekend and early next week. Additionally, there is a slight chance for the system to become severe. Latest guidance suggests that 08U should reach its most eastern location within the next 24 hours. The most likely track scenario is for 08U to remain off the Western Australian coast as it curves towards the southwest over the weekend and into next week. But the potential for more southerly movement over the weekend means an approach close to or across the western Pilbara coast early next week remains possible. Copyright Commonwealth of Australia == The next bulletin for this system will be issued by: 14/1930 UTC.
Time (AWST) Intensity Category Latitude
(decimal deg.)Longitude
(decimal deg.)Estimated Position
Accuracy (km)0hr 8 pm March 14 tropical low 16.9S 115.4E 75 +6hr 2 am March 15 tropical low 17.2S 115.6E 100 +12hr 8 am March 15 tropical low 17.4S 115.7E 125 +18hr 2 pm March 15 tropical low 17.6S 115.7E 135 +24hr 8 pm March 15 tropical low 17.8S 115.6E 145 +36hr 8 am March 16 tropical low 17.9S 115.1E 165 +48hr 8 pm March 16 tropical low 18.1S 114.6E 205 +60hr 8 am March 17 1 18.3S 114.1E 255 +72hr 8 pm March 17 1 18.8S 113.8E 285 最后于 2024-03-14 21:25:00 被ygsj24编辑 ，原因： -
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WDXS32 PGTW 141500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 014// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 17.0S 115.8E INITIAL INTENSITY: 35 KTS GEOGRAPHIC REFERENCE: 332 NM NORTH-NORTHEAST OF LEARMONTH, AUSTRALIA MOVEMENT PAST 6 HOURS: SOUTHEASTWARD AT 11 KTS SIGNIFICANT WAVE HEIGHT: 16 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: TROPICAL CYCLONE (TC) 18S HAS SHOWN SIGNS OF INCREASED CONSOLIDATION AS VERTICAL WIND SHEAR (VWS) HAS DECREASED IN CLOSE PROXIMITY TO THE CENTRAL CORE AND THE ONCE FULLY-EXPOSED CENTER HAS BECOME COMPLETELY OBSCURED BY INCREASED FLARING CONVECTION OVER THE LOW-LEVEL CIRCULATION CENTER (LLCC), AS REVEALED IN THE ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY. MODERATE EQUATORWARD OUTFLOW IS NOW EVIDENT OVER THE SURFACE CIRCULATION, AS UPPER-LEVEL OUTFLOW HAS CONTINUED TO AID IN THE OVERALL CONSOLIDATION OF THE SYSTEM THROUGHOUT THE LAST SIX HOURS. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON A 141106Z 37 GHZ SSMIS MICROWAVE IMAGE. AN EARLIER 140202Z ASCAT-C IMAGE HAS SHOWN AN ASYMMETRIC WIND FIELD WITH A SWATH OF 35 KNOT WINDS TO THE NORTH, WHICH SUPPORTS THE INITIAL INTENSITY ASSESSMENT OF 35 KNOTS WITH MEDIUM CONFIDENCE. AGENCY SUBJECTIVE DVORAK ESTIMATES CONTINUE TO REMAIN SLIGHTLY LOWER AT 30 KNOTS, WITH UW-CIMSS ADT AND AIDT ESTIMATES RANGING BETWEEN 29 TO 31 KNOTS. INITIAL WIND RADII BASIS: SCATTEROMETER DATA CURRENT STEERING MECHANISM: NEAR-EQUATORIAL RIDGE (NER) ENTRENCHED TO THE NORTH, WITH A BUILDING SUBTROPICAL RIDGE (STR) TO THE SOUTH. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T2.0 - 30 KTS KNES: T2.0 - 30 KTS DEMS: T2.0 - 30 KTS APRF: T1.5 - 25 KTS CIMSS ADT: 29 KTS AT 141200Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE VWS: 10-15 KTS SST: 30-31 CELSIUS OUTFLOW: MODERATE EQUATORWARD 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 TRACK SOUTHEASTWARD THROUGH TAU 12. HOWEVER, THE SYSTEM IS EXPECTED TO CONTINUE SLOWING DOWN AND GRADUALLY TURN SOUTHWARD TO SOUTHWESTWARD THROUGH TAU 42 AS THE AFOREMENTIONED WESTWARD BUILDING STR TO THE SOUTH BECOMES THE DOMINANT STEERING INFLUENCE. TC 18S IS FORECAST TO MAINTAIN WEAK TROPICAL STORM STRENGTH THROUGH TAU 48 DUE TO THE MARGINAL UPPER-LEVEL CONDITIONS. AFTER TAU 48, VERTICAL WIND SHEAR (VWS) IS EXPECTED TO CONTINUE DECREASING, ALLOWING THE SYSTEM TO CONSOLIDATE FURTHER. AFTER TAU 48, TC 18S WILL TRACK SLOWLY SOUTH-SOUTHWESTWARD TOWARD A BREAK IN THE STR STEERING PATTERN ASSOCIATED WITH AN APPROACHING SHORTWAVE TROUGH AND FRONTAL SYSTEM. AFTER TAU 90, A STRONG LOW-LEVEL HIGH IS EXPECTED TO BUILD TO THE SOUTH OVER WESTERN AUSTRALIA, EFFECTIVELY BLOCKING AND SLOWING POLEWARD PROGRESSION. AFTER TAU 66, ENVIRONMENTAL CONDITIONS APPEAR INCREASINGLY CONDUCIVE, WITH LOW VWS AND IMPROVING POLEWARD OUTFLOW INTO THE MIDLATITUDE EQUATORWARD-EXTENDING SHORTWAVE TROUGH, WHICH WILL RESULT IN MODERATE INTENSIFICATION TO A PEAK INTENSITY OF 70 KNOTS BY TAU 96 AND THROUGH THE REMAINDER OF THE FORECAST PERIOD. MODEL DISCUSSION: WITH THE EXCEPTION OF NAVGEM AND THE ECMWF ENSEMBLE MEAN, DETERMINISTIC NUMERICAL MODEL TRACK GUIDANCE REMAINS IN FAIR AGREEMENT THROUGH TAU 72 WITH A 117 NM CROSS-TRACK SPREAD AT TAU 72 THEN POOR AGREEMENT AFTER TAU 72 WITH A 254 NM CROSS-TRACK SPREAD AT TAU 120. THE 140600Z ECMWF ENSEMBLE (EPS) AND GFS ENSEMBLE (GEFS) ALSO INDICATE CONTINUED AND INCREASING UNCERTAINTY AFTER TAU 72, WITH A VERY LARGE SPREAD IN SOLUTIONS. THE 140600Z COAMPS-TC INTENSITY ENSEMBLE (CTCXEPS) SHOWS INCREASING INTENSITY PROBABILITIES OF MODERATE INTENSIFICATION, WITH PEAK PROBABILITY VALUES RANGING FROM 50 TO 80 PERCENT FROM TAU 54 TO TAU 90. RAPID INTENSIFICATION PROBABILITIES REMAIN LOW AT LESS THAN 25 PERCENT THROUGHOUT THE 120 HOUR FORECAST. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: LOW INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: LOW// NNNN
最后于 2024-03-15 18:20:00 被ygsj24编辑 ，原因： -
AXAU01 APRF 141854 IDW27600 TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE at: 1854 UTC 14/03/2024 Name: Tropical Low Identifier: 08U Data At: 1800 UTC Latitude: 17.3S Longitude: 115.7E Location Accuracy: within 40nm (75 km) Movement Towards: south southeast (147 deg) Speed of Movement: 7 knots (13 km/h) Maximum 10-Minute Wind: 35 knots (65 km/h) Maximum 3-Second Wind Gust: 50 knots (95 km/h) Central Pressure: 993 hPa Radius of 34-knot winds NE quadrant: 100 nm (185 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: T1.5/1.5/S0.0/24HRS STT:S0.0/06HRS 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: 15/0000: 17.5S 115.7E: 055 (105): 035 (065): 993 +12: 15/0600: 17.7S 115.7E: 070 (125): 035 (065): 993 +18: 15/1200: 17.9S 115.6E: 075 (135): 030 (055): 996 +24: 15/1800: 17.9S 115.4E: 085 (155): 030 (055): 996 +36: 16/0600: 18.1S 114.8E: 090 (170): 030 (055): 996 +48: 16/1800: 18.3S 114.4E: 105 (195): 035 (065): 993 +60: 17/0600: 18.6S 114.0E: 135 (255): 040 (075): 990 +72: 17/1800: 19.1S 113.6E: 160 (295): 050 (095): 982 +96: 18/1800: 20.4S 112.8E: 215 (395): 055 (100): 978 +120: 19/1800: 21.6S 111.7E: 280 (515): 045 (085): 985 REMARKS: Strong easterly wind shear continues to influence 08U with the low level circulation exposed. Deep convection is located more than 90nm to the northwest. Position is based on animated IR imagery and persistence. Dvorak analysis: Shear pattern gives DT1.5. MET is 1.5 on a 24 hour S trend, and PT agrees. FT of 1.5 based on MET/PAT. Objective guidance: ADT 32kn, AiDT 35kn and DPRINT 27kn (all 1-min average). Intensity has been maintained at 35kn in the northern quadrants. 08U has been moving more to the south-southeast. Development continues to be constrained by strong easterly shear (~30 knots). Environmental conditions are otherwise somewhat favourable with SSTs 28-29C along track. Shear is expected to ease and become more northerly during the weekend, and upper level winds are forecast to become supportive of poleward outflow. The result of reduction in deep layer wind shear should allow the system to begin to develop, and tropical cyclone strength is currently forecast from Sunday. Further intensification is possible as 08U tracks southwest under the influence of the ridge over the weekend and early next week. There is a slight chance for the system to become severe, if it tracks north of west early next week. The most likely track scenario is for 08U to remain off the Western Australian coast as it curves towards the southwest tonight and continues to move southwest during the weekend. A slight risk of potential for a continued southerly movement remains over the weekend, in which case 08U may move close to or across the western Pilbara coast early next week. Copyright Commonwealth of Australia == The next bulletin for this system will be issued by: 15/0130 UTC.
Time (AWST) Intensity Category Latitude
(decimal deg.)Longitude
(decimal deg.)Estimated Position
Accuracy (km)0hr 2 am March 15 tropical low 17.3S 115.7E 75 +6hr 8 am March 15 tropical low 17.5S 115.7E 105 +12hr 2 pm March 15 tropical low 17.7S 115.7E 125 +18hr 8 pm March 15 tropical low 17.9S 115.6E 135 +24hr 2 am March 16 tropical low 17.9S 115.4E 155 +36hr 2 pm March 16 tropical low 18.1S 114.8E 170 +48hr 2 am March 17 tropical low 18.3S 114.4E 195 +60hr 2 pm March 17 1 18.6S 114.0E 255 +72hr 2 am March 18 2 19.1S 113.6E 295 -
WTXS32 PGTW 142100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 015// RMKS/ 1. TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 015 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 141800Z --- NEAR 17.3S 115.4E MOVEMENT PAST SIX HOURS - 180 DEGREES AT 06 KTS POSITION ACCURATE TO WITHIN 025 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 - 040 NM NORTHEAST QUADRANT 000 NM SOUTHEAST QUADRANT 065 NM SOUTHWEST QUADRANT 075 NM NORTHWEST QUADRANT REPEAT POSIT: 17.3S 115.4E --- FORECASTS: 12 HRS, VALID AT: 150600Z --- 17.8S 115.4E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT 010 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 215 DEG/ 02 KTS --- 24 HRS, VALID AT: 151800Z --- 18.2S 115.1E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 030 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 230 DEG/ 03 KTS --- 36 HRS, VALID AT: 160600Z --- 18.6S 114.6E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 030 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 230 DEG/ 03 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 161800Z --- 19.0S 114.1E MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 000 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 230 DEG/ 02 KTS --- 72 HRS, VALID AT: 171800Z --- 19.6S 113.3E MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 090 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 245 DEG/ 03 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 181800Z --- 20.1S 112.2E MAX SUSTAINED WINDS - 065 KT, GUSTS 080 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 030 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT VECTOR TO 120 HR POSIT: 250 DEG/ 03 KTS --- 120 HRS, VALID AT: 191800Z --- 20.5S 111.0E MAX SUSTAINED WINDS - 065 KT, GUSTS 080 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 - 030 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 090 NM NORTHWEST QUADRANT --- REMARKS: 142100Z POSITION NEAR 17.4S 115.4E. 14MAR24. TROPICAL CYCLONE 18S (EIGHTEEN), LOCATED APPROXIMATELY 309 NM NORTH-NORTHEAST OF LEARMONTH, AUSTRALIA, HAS TRACKED SOUTHWARD AT 06 KNOTS OVER THE PAST SIX HOURS. MINIMUM CENTRAL PRESSURE AT 141800Z IS 998 MB. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 141800Z IS 14 FEET. NEXT WARNINGS AT 150300Z, 150900Z, 151500, AND 152100.// NNNN
WDXS32 PGTW 142100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 015// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 17.3S 115.4E INITIAL INTENSITY: 35 KTS GEOGRAPHIC REFERENCE: 309 NM NORTH-NORTHEAST OF LEARMONTH, AUSTRALIA MOVEMENT PAST 6 HOURS: SOUTHWARD AT 06 KTS SIGNIFICANT WAVE HEIGHT: 14 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS THE FLARING DEEP CENTRAL CONVECTION SHEARED WESTWARD OF A PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC). THERE IS MODERATE POLEWARD OUTFLOW BUT NO ORGANIZED FEEDER BANDS. ANALYSIS INDICATES A MARGINAL ENVIRONMENT WITH VERY WARM SST AND MODERATE POLEWARD OUTFLOW ALOFT GREATLY OFFSET BY 20-25 KTS OF VERTICAL WIND SHEAR (VWS). THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE PARTLY EXPOSED LLCC IN THE EIR LOOP. THE INITIAL INTENSITY IS ALSO PLACED WITH MEDIUM CONFIDENCE BASED ON OVERALL ASSESSMENT OF AGENCY AND OBJECTIVE DVORAK INTENSITY ESTIMATES AND REFLECTS THE SUSTAINED 6-HR CONVECTIVE SIGNATURE. INITIAL WIND RADII BASIS: MOST RECENT STORM-CENTERED SCATTEROMETER DATA. CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE SOUTHEAST ANCHORED OVER CENTRAL AUSTRALIA. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T2.0 - 30 KTS KNES: T1.5 - 25 KTS CIMSS ADT: 32 KTS AT 141730Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL VWS: 20-25 KTS SST: 30-31 CELSIUS OUTFLOW: MODERATE POLEWARD 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 WILL TRACK MORE SOUTHWESTWARD AS THE STR BUILDS AND EXTENDS WESTWARD. AS THE STORM MOTION BECOMES MORE IN-PHASE WITH THE UPPER-LEVEL WIND FLOW, VWS IS EXPECTED TO WEAKEN, AND POLEWARD OUTFLOW TO IMPROVE, PROMOTING A STEADY INTENSIFICATION, REACHING 65KTS BY TAU 96. MODEL DISCUSSION: NUMERICAL MODELS EVENLY SPREAD OUT TO 145NM BY TAU 72, LENDING MEDIUM CONFIDENCE TO THE NEAR- TO MID-PORTION OF THE JTWC TRACK FORECAST. AFTERWARD, THE SPREAD BECOMES A LOT MORE UNEVEN AND WIDER TO 440NM BY TAU 120 WITH GFS ON THE RIGHT AND NAVGEM ON THE LEFT MARGIN OF THE MODEL ENVELOPE, LENDING LOW CONFIDENCE TO THE EXTENDED PORTION OF THE JTWC TRACK FORECAST. 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 150124 IDW27600 TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE at: 0124 UTC 15/03/2024 Name: Tropical Low Identifier: 08U Data At: 0000 UTC Latitude: 17.3S Longitude: 115.6E Location Accuracy: within 40nm (75 km) Movement Towards: south southeast (154 deg) Speed of Movement: 2 knots (4 km/h) Maximum 10-Minute Wind: 35 knots (65 km/h) Maximum 3-Second Wind Gust: 50 knots (95 km/h) Central Pressure: 993 hPa Radius of 34-knot winds NE quadrant: Radius of 34-knot winds SE quadrant: Radius of 34-knot winds SW quadrant: Radius of 34-knot winds NW quadrant: 100 nm (185 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 SST:D0.5/06HRS Pressure of outermost isobar: 1002 hPa Radius of outermost closed isobar: 160 nm (295 km) FORECAST DATA Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure (UTC) : degrees : nm (km): knots(km/h): hPa +06: 15/0600: 17.5S 115.6E: 055 (100): 035 (065): 993 +12: 15/1200: 17.8S 115.5E: 065 (125): 030 (055): 996 +18: 15/1800: 17.9S 115.2E: 075 (140): 030 (055): 996 +24: 16/0000: 17.9S 114.8E: 080 (150): 030 (055): 996 +36: 16/1200: 18.1S 114.2E: 080 (150): 030 (055): 997 +48: 17/0000: 18.2S 113.7E: 100 (185): 035 (065): 993 +60: 17/1200: 18.6S 113.3E: 130 (240): 040 (075): 990 +72: 18/0000: 19.1S 112.8E: 150 (280): 045 (085): 982 +96: 19/0000: 19.8S 111.8E: 210 (390): 050 (095): 982 +120: 20/0000: 20.2S 110.4E: 275 (505): 045 (085): 986 REMARKS: The low level centre remains exposed but closer to improving convection to the west than it was 6 hours due to a slight decrease in easterly shear. In the last hour shallow convection has started to develop on the northeast quadrant. The low level centre is a little broad and located using animated visible imagery, with a moderate confidence in position. Dvorak analysis: Shear pattern gives DT2.5. MET is 2.5 on a 24 hour D trend. PAT reduced to 2.0 due to the broad LLC. FT of 2.0 based on PAT. Objective guidance: ADT 31kn, AiDT 31kn and DPRINT 25kn (all 1-min average). Intensity has been maintained at 35kn in the northeast quadrant based on the AMSR2 SMAP microwave pass at 1756 UTC. 08U has become slow moving to the south. Development of the system has slightly improved with strong easterly shear dropping slightly to 20-25 kn (CIMMS shear 1800 UTC) though overall is expected to remain high (20-30 kn) over the next 12 to 24 hours, stagnating development. Quadrant gales are forecast to ease from later today till Sunday morning. Environmental conditions are otherwise somewhat favourable with SSTs 28-29C along track. Shear is expected to ease and become more northerly over the weekend as the system moves south, and upper level winds are forecast to become supportive of poleward outflow. The result of reduction in deep layer wind shear should allow the system to begin to develop from later Saturday, and tropical cyclone strength is currently forecast from later Sunday or early Monday. Further intensification is possible as 08U tracks southwest under the influence of the ridge over the weekend and early next week. There is a slight chance for the system to become severe, if it tracks north of west early next week. The most likely track scenario is for 08U to remain off the Western Australian coast as it curves towards the southwest tonight and continues to move southwest during the weekend. A slight, and slowly decreasing risk of the system having a more southerly movement over the weekend, in which case 08U may move close to or across the western Pilbara coast early next week. Copyright Commonwealth of Australia == The next bulletin for this system will be issued by: 15/0730 UTC.
Time (AWST) Intensity Category Latitude
(decimal deg.)Longitude
(decimal deg.)Estimated Position
Accuracy (km)0hr 8 am March 15 tropical low 17.3S 115.6E 75 +6hr 2 pm March 15 tropical low 17.5S 115.6E 100 +12hr 8 pm March 15 tropical low 17.8S 115.5E 125 +18hr 2 am March 16 tropical low 17.9S 115.2E 140 +24hr 8 am March 16 tropical low 17.9S 114.8E 150 +36hr 8 pm March 16 tropical low 18.1S 114.2E 150 +48hr 8 am March 17 tropical low 18.2S 113.7E 185 +60hr 8 pm March 17 1 18.6S 113.3E 240 +72hr 8 am March 18 1 19.1S 112.8E 280 -
WTXS32 PGTW 150300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 016// RMKS/ 1. TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 016 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 150000Z --- NEAR 17.7S 115.2E MOVEMENT PAST SIX HOURS - 205 DEGREES AT 04 KTS POSITION ACCURATE TO WITHIN 025 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 - 030 NM NORTHEAST QUADRANT 000 NM SOUTHEAST QUADRANT 045 NM SOUTHWEST QUADRANT 065 NM NORTHWEST QUADRANT REPEAT POSIT: 17.7S 115.2E --- FORECASTS: 12 HRS, VALID AT: 151200Z --- 18.1S 115.0E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 030 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 230 DEG/ 02 KTS --- 24 HRS, VALID AT: 160000Z --- 18.4S 114.6E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 240 DEG/ 03 KTS --- 36 HRS, VALID AT: 161200Z --- 18.7S 114.1E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 020 NM NORTHEAST QUADRANT 090 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 240 DEG/ 03 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 170000Z --- 19.0S 113.6E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 030 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 245 DEG/ 02 KTS --- 72 HRS, VALID AT: 180000Z --- 19.4S 112.7E MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 250 DEG/ 03 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 190000Z --- 19.8S 111.6E MAX SUSTAINED WINDS - 060 KT, GUSTS 075 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 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT VECTOR TO 120 HR POSIT: 260 DEG/ 04 KTS --- 120 HRS, VALID AT: 200000Z --- 20.0S 110.0E MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 080 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT --- REMARKS: 150300Z POSITION NEAR 17.8S 115.2E. 15MAR24. TROPICAL CYCLONE 18S (EIGHTEEN), LOCATED APPROXIMATELY 283 NM NORTH-NORTHEAST OF LEARMONTH, AUSTRALIA, HAS TRACKED SOUTH-SOUTHWESTWARD AT 04 KNOTS OVER THE PAST SIX HOURS. MINIMUM CENTRAL PRESSURE AT 150000Z IS 998 MB. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 150000Z IS 14 FEET. NEXT WARNINGS AT 150900Z, 151500Z, 152100Z AND 160300Z.// NNNN
WDXS32 PGTW 150300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 016// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 17.7S 115.2E INITIAL INTENSITY: 35 KTS GEOGRAPHIC REFERENCE: 283 NM NORTH-NORTHEAST OF LEARMONTH, AUSTRALIA MOVEMENT PAST 6 HOURS: SOUTH-SOUTHWESTWARD AT 04 KTS SIGNIFICANT WAVE HEIGHT: 14 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY SHOWS THE DEEP FLARING CENTRAL CONVECTION SHEARED WESTWARD OF AND MOSTLY OBSCURING THE LEVEL CIRCULATION CENTER (LLCC). THERE IS MODERATE POLEWARD OUTFLOW BUT NO ORGANIZED CONVECTIVE FEEDER BANDS. ANALYSIS INDICATES A MARGINAL ENVIRONMENT WITH VERY WARM SST AND MODERATE POLEWARD OUTFLOW ALOFT OFFSET BY 20-25 KTS OF VERTICAL WIND SHEAR (VWS). THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON A MICROWAVE LLCC FEATURE IN THE 142218Z SSMIS IMAGE SUITE. THE INITIAL INTENSITY IS ALSO PLACED WITH MEDIUM CONFIDENCE AND HELD SLIGHTLY HIGHER THAN THE AGENCY AND OBJECTIVE DVORAK INTENSITY ESTIMATES TO REFLECT THE SUSTAINED 6-HR CONVECTIVE SIGNATURE. INITIAL WIND RADII BASIS: MOST RECENT STORM-CENTERED SCATTEROMETER DATA. CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE SOUTHEAST ANCHORED OVER CENTRAL AUSTRALIA. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T2.0 - 30 KTS DEMS: T2.0 - 30 KTS APRF: T1.5 - 25 KTS CIMSS ADT: 32 KTS AT 142020Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL VWS: 20-25 KTS SST: 29-30 CELSIUS OUTFLOW: MODERATE POLEWARD 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 WILL TRACK MORE SOUTHWESTWARD THEN WEST-SOUTHWESTWARD AS THE STR BUILDS AND EXTENDS WESTWARD. AS THE STORM MOTION BECOMES MORE IN-PHASE WITH THE UPPER-LEVEL WIND FLOW, VWS IS EXPECTED TO WEAKEN, AND POLEWARD OUTFLOW TO IMPROVE, PROMOTING A STEADY INTENSIFICATION, PEAKING 60KTS BY TAU 96. AFTERWARD, COLD DRY AIR INTRUSION WILL MOSTLY BE RESPONSIBLE FOR A GRADUAL WEAKENING DOWN TO 55KTS BY TAU 120. MODEL DISCUSSION: NUMERICAL MODELS EVENLY SPREAD OUT TO 150NM BY TAU 72, LENDING MEDIUM CONFIDENCE TO THE NEAR- TO MID-PORTION OF THE JTWC TRACK FORECAST. AFTERWARD, THE SPREAD BECOMES A LOT MORE UNEVEN AND SIGNIFICANTLY WIDER TO 695NM BY TAU 120 WITH ECMWF ON THE RIGHT AND NAVGEM ON THE LEFT MARGIN OF THE MODEL ENVELOPE, LENDING LOW CONFIDENCE TO THE EXTENDED PORTION OF THE JTWC TRACK FORECAST. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: LOW INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: LOW// NNNN
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AXAU01 APRF 150707 IDW27600 TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE at: 0707 UTC 15/03/2024 Name: Tropical Low Identifier: 08U Data At: 0600 UTC Latitude: 17.5S Longitude: 115.3E Location Accuracy: within 40nm (75 km) Movement Towards: southwest (216 deg) Speed of Movement: 2 knots (5 km/h) Maximum 10-Minute Wind: 30 knots (55 km/h) Maximum 3-Second Wind Gust: 45 knots (85 km/h) Central Pressure: 996 hPa Radius of 34-knot winds NE quadrant: Radius of 34-knot winds SE quadrant: Radius of 34-knot winds SW quadrant: Radius of 34-knot winds NW quadrant: Radius of 48-knot winds NE quadrant: Radius of 48-knot winds SE quadrant: Radius of 48-knot winds SW quadrant: Radius of 48-knot winds NW quadrant: Radius of 64-knot winds: nm ( km) Radius of Maximum Winds: nm ( km) Dvorak Intensity Code: T2.0/2.0/D1.0/24HRS SST:S0.0/06HRS Pressure of outermost isobar: 1002 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: 15/1200: 17.6S 115.3E: 055 (105): 030 (055): 996 +12: 15/1800: 17.7S 115.1E: 070 (130): 030 (055): 996 +18: 16/0000: 17.7S 115.0E: 080 (145): 030 (055): 996 +24: 16/0600: 17.8S 114.8E: 080 (150): 030 (055): 996 +36: 16/1800: 17.8S 114.2E: 090 (170): 030 (055): 996 +48: 17/0600: 18.0S 113.7E: 115 (210): 035 (065): 993 +60: 17/1800: 18.3S 113.3E: 140 (255): 045 (085): 986 +72: 18/0600: 18.7S 112.9E: 170 (310): 045 (085): 982 +96: 19/0600: 19.1S 112.0E: 215 (395): 050 (095): 982 +120: 20/0600: 18.8S 110.2E: 285 (530): 040 (075): 990 REMARKS: The low level centre remains exposed to the deep convection to the west and confidence in position is poor due to high cloud masking it. Deep convection remains around 45 nautical miles from the low level centre with high easterly shear. Dvorak analysis: Shear pattern gives DT2.5. MET is 2.0 on a 24 hour D- trend. PAT agrees. FT of 2.0 based on MET/PAT. Recent objective guidance: ADT 33kn and AiDT 31kn (all 1-min average). Intensity has reduced to 30 knots, in agreeance with guidance and recent weakening the system. 08U has become slow moving to the southwest. Development of the system has slightly improved with strong easterly shear dropping slightly to 20-25 kn (CIMMS shear 0000 UTC) though overall is expected to remain high (20-30 kn) over the next 12 to 36 hours, stagnating development. Quadrant gales has eased. Environmental conditions are otherwise somewhat favourable with SSTs 28-29C along track. Shear is expected to ease and become more northerly from later Saturday or Sunday as the system moves south, and upper level winds are forecast to become supportive of poleward outflow. The result of reduction in deep layer wind shear should allow the system to begin to develop from Sunday, and tropical cyclone strength is currently forecast from Monday. Further intensification is possible as 08U tracks west or southwest under the influence of the ridge over the weekend and early next week. There is a slight chance for the system to become severe, if it tracks north of west early next week. The most likely track scenario is for 08U to remain off the Western Australian coast as it curves towards the southwest tonight and continues to move west or southwest during the weekend. Recent guidance has the system remaining slow moving until Monday well off the Pilbara coast before taking a more west or southwest track away from Western Australia. A slight, and slowly decreasing risk of the system having a more southerly movement over the weekend, in which case 08U may move close to or across the western Pilbara coast early next week. Copyright Commonwealth of Australia == The next bulletin for this system will be issued by: 15/1330 UTC.
Time (AWST) Intensity Category Latitude
(decimal deg.)Longitude
(decimal deg.)Estimated Position
Accuracy (km)0hr 2 pm March 15 tropical low 17.5S 115.3E 75 +6hr 8 pm March 15 tropical low 17.6S 115.3E 105 +12hr 2 am March 16 tropical low 17.7S 115.1E 130 +18hr 8 am March 16 tropical low 17.7S 115.0E 145 +24hr 2 pm March 16 tropical low 17.8S 114.8E 150 +36hr 2 am March 17 tropical low 17.8S 114.2E 170 +48hr 2 pm March 17 tropical low 18.0S 113.7E 210 +60hr 2 am March 18 1 18.3S 113.3E 255 +72hr 2 pm March 18 1 18.7S 112.9E 310 -
WTXS32 PGTW 150900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 017// RMKS/ 1. TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 017 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 150600Z --- NEAR 17.8S 114.8E MOVEMENT PAST SIX HOURS - 240 DEGREES AT 04 KTS POSITION ACCURATE TO WITHIN 050 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 - 030 NM NORTHEAST QUADRANT 025 NM SOUTHEAST QUADRANT 000 NM SOUTHWEST QUADRANT 065 NM NORTHWEST QUADRANT REPEAT POSIT: 17.8S 114.8E --- FORECASTS: 12 HRS, VALID AT: 151800Z --- 18.0S 114.5E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT 010 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 255 DEG/ 02 KTS --- 24 HRS, VALID AT: 160600Z --- 18.1S 114.1E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 255 DEG/ 02 KTS --- 36 HRS, VALID AT: 161800Z --- 18.2S 113.7E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 235 DEG/ 02 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 170600Z --- 18.4S 113.4E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 260 DEG/ 01 KTS --- 72 HRS, VALID AT: 180600Z --- 18.5S 112.9E MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 020 NM NORTHEAST QUADRANT 020 NM SOUTHEAST QUADRANT 020 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 030 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 270 DEG/ 02 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 190600Z --- 18.5S 112.0E MAX SUSTAINED WINDS - 060 KT, GUSTS 075 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 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 030 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT VECTOR TO 120 HR POSIT: 290 DEG/ 04 KTS --- 120 HRS, VALID AT: 200600Z --- 17.9S 110.3E MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT 010 NM SOUTHEAST QUADRANT 010 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT --- REMARKS: 150900Z POSITION NEAR 17.9S 114.7E. 15MAR24. TROPICAL CYCLONE 18S (EIGHTEEN), LOCATED APPROXIMATELY 273 NM NORTH OF LEARMONTH, AUSTRALIA, HAS TRACKED WEST-SOUTHWESTWARD AT 04 KNOTS OVER THE PAST SIX HOURS. MINIMUM CENTRAL PRESSURE AT 150600Z IS 996 MB. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 150600Z IS 15 FEET. NEXT WARNINGS AT 151500Z, 152100Z, 160300Z AND 160900Z.// NNNN
WDXS32 PGTW 150900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 017// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 17.8S 114.8E INITIAL INTENSITY: 35 KTS GEOGRAPHIC REFERENCE: 273 NM NORTH OF LEARMONTH, AUSTRALIA MOVEMENT PAST 6 HOURS: WEST-SOUTHWESTWARD AT 04 KTS SIGNIFICANT WAVE HEIGHT: 15 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: TROPICAL CYCLONE (TC) 18S HAS CONTINUED TO SHOW SIGNS OF SLOW CONSOLIDATION WITH SUSTAINED CONVECTION IN CLOSE PROXIMITY TO THE LOW-LEVEL CIRCULATION CENTER (LLCC). HOWEVER, THE SURFACE CENTER REMAINS PARTIALLY EXPOSED BETWEEN TWO CONVECTIVE STRUCTURES ON THE EASTERN AND WESTERN FLANKS OF THE LOW-LEVEL CURVED CLOUD LINES WRAPPING INTO THE TIGHTEST TURNING, AS REVEALED IN THE ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI). WEAK EQUATORWARD OUTFLOW IS EVIDENT OVER THE LLCC, AS UPPER-LEVEL OUTFLOW CONTINUES TO MAINTAIN THE VERY SLOW INTENSIFICATION TREND. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON A 150609Z 89 GHZ AMSR2 MICROWAVE IMAGE. THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON UW-CIMSS OBJECTIVE INTENSITY ESTIMATES RANGING BETWEEN 32-33 KTS, WHILE SUBJECTIVE DVORAK ESTIMATES ASSESS TC 18S BETWEEN 30-35 KNOTS. INITIAL WIND RADII BASIS: OBTK CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE SOUTH, LOCATED OVER CENTRAL AUSTRALIA AND EXTENDING WESTWARD INTO THE SOUTHERN INDIAN OCEAN. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T2.5 - 35 KTS KNES: T2.0 - 30 KTS DEMS: T2.0 - 30 KTS APRF: T2.0 - 30 KTS CIMSS ADT: 33 KTS AT 150610Z CIMSS AIDT: 32 KTS AT 150610Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE VWS: 20-25 KTS SST: 29-30 CELSIUS OUTFLOW: WEAK EQUATORWARD ANALYSIS CONFIDENCE: INITIAL POSITION: MEDIUM INITIAL INTENSITY: MEDIUM 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 CURRENTLY TRACKING SOUTHWESTWARD ALONG THE WESTERN PERIPHERY OF THE STR LOCATED OVER CENTRAL AUSTRALIA AND EXTENDING WESTWARD INTO THE SOUTHERN INDIAN OCEAN (IO). AS THE AFOREMENTIONED DEEP-LAYER STR CONTINUES TO BUILD WESTWARD, TC 18S IS EXPECTED TO SLOW AND MOVE GENERALLY WEST- SOUTHWESTWARD THROUGH TAU 72. AFTER TAU 72, AN EQUATORWARD-EXTENDING DEEP LONGWAVE TROUGH WILL WEAKEN THE STR, HOWEVER, A STRONG LOW-LEVEL HIGH PRESSURE BEGINS BUILDING INTO THE SOUTHERN IO. AS THE HIGH BUILDS OVER THE SOUTHERN IO, TC 18S WILL BEGIN A WEST-NORTHWESTWARD TRACK ALONG THE NORTHERN PERIPHERY OF THE SOUTHEAST TRADE FLOW THROUGH TAU 120. THE CYCLONE IS EXPECTED TO ENTER A MORE CONDUCIVE ENVIRONMENT AS VERTICAL WIND SHEAR (VWS) DECREASES (10-15 KNOTS), AND SEA SURFACE TEMPERATURES SUSTAIN BETWEEN 29-31C, RESULTING IN A STEADY INCREASE IN INTENSITY THROUGH TAU 72 UP TO 45 KNOTS, AND A PEAK UPWARDS OF 60 KNOTS INTO TAU 96. AFTER TAU 96, A GRADUAL WEAKENING TREND IS EXPECTED AS DRY AIR BEGINS SLOWLY WRAPPING AROUND THE NORTHERN QUADRANT, LIMITING FURTHER TC DEVELOPMENT. MODEL DISCUSSION: WITH THE EXCEPTION OF NAVGEM, THE DETERMINISTIC MODEL TRACK GUIDANCE CONTINUES TO IMPROVE IN AGREEMENT THROUGH TAU 72 WITH A CROSS-TRACK SPREAD OF 70 NM, INCREASING SIGNIFICANTLY THROUGH TAU 120 WITH A CROSS-TRACK SPREAD OF 215 NM. THE 150000Z ECMWF ENSEMBLE (EPS) AND GFS ENSEMBLE (GEFS) ALSO INDICATE CONTINUED UNCERTAINTY AFTER TAU 72, WITH A DIVERGENT SPREAD IN SOLUTIONS. THE 150000Z COAMPS-TC INTENSITY ENSEMBLE (CTCXEPS) SHOWS A STEADY INTENSIFICATION TREND, WITH PEAK PROBABILITIES REACHING MODERATE INTENSIFICATION OF 30 TO 40 PERCENT BETWEEN TAU 48 AND TAU 60. 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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IDW24000 Australian Bureau of Meteorology Tropical Cyclone Warning Centre TROPICAL CYCLONE INFORMATION BULLETIN Issued at 8:50 pm WST on Friday 15 March 2024 A Tropical Low was located at 8:00 pm AWST near 17.6S 115.1E, that is 395 km north northwest of Karratha and 495 km north northeast of Exmouth, and slow moving. Tropical Low 08U is located well to the north of the Pilbara coast and is slowly moving southwest. It is expected to track slowly west or southwest over weekend, parallel to the Pilbara coast. It is not expected to develop rapidly but may reach tropical cyclone strength Monday. Peripheral impacts are a small possibility along the Pilbara coast during Monday and Tuesday. Even though the centre of Tropical Low 08U is highly likely to remain offshore, there is a slight chance it could continue moving further south late weekend. If this happens, then it may reach the west Pilbara coast early next week, but this is looking unlikely. The next Information Bulletin will be issued at 3 am AWST.
Time (AWST) Intensity Category Latitude
(decimal deg.)Longitude
(decimal deg.)Estimated Position
Accuracy (km)0hr 8 pm March 15 tropical low 17.6S 115.1E 85 +6hr 2 am March 16 tropical low 17.7S 115.0E 110 +12hr 8 am March 16 tropical low 17.7S 114.7E 130 +18hr 2 pm March 16 tropical low 17.8S 114.5E 135 +24hr 8 pm March 16 tropical low 17.8S 114.2E 140 +36hr 8 am March 17 tropical low 17.7S 113.5E 180 +48hr 8 pm March 17 tropical low 17.9S 113.2E 215 +60hr 8 am March 18 1 18.2S 112.7E 260 +72hr 8 pm March 18 2 18.5S 112.4E 295 最后于 2024-03-16 06:00:00 被ygsj24编辑 ，原因：