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WDXS32 PGTW 151500 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 018// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 17.9S 114.2E INITIAL INTENSITY: 35 KTS GEOGRAPHIC REFERENCE: 264 NM NORTH OF LEARMONTH, AUSTRALIA MOVEMENT PAST 6 HOURS: WESTWARD AT 06 KTS SIGNIFICANT WAVE HEIGHT: 14 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: TROPICAL CYCLONE (TC) 18S HAS CONTINUED TO DEPICT SIGNS OF SLOW CONSOLIDATION WITH PERSISTENT DEEP CONVECTION AND ASSOCIATED OVERSHOOTING TOPS JUST WEST OF THE LOW-LEVEL CIRCULATION CENTER (LLCC). THE SURFACE CENTER HAS BECOME INCREASINGLY OBSCURED BETWEEN TWO CONVECTIVE STRUCTURES JUST TO THE EAST AND WEST, WITH OBSERVABLE WARMING TOPS OVER THE LAST FEW HOURS AS REVEALED IN THE ANIMATED ENHANCED INFRARED SATELLITE IMAGERY. WEAK RADIAL OUTFLOW IS EVIDENT OVER THE LLCC, AS UPPER-LEVEL OUTFLOW FROM ASSOCIATED CONVECTION CONTINUES TO FUEL THE ONGOING AND SLOW INTENSIFICATION TREND. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON A 151052Z 37 GHZ SSMIS MICROWAVE IMAGE. THE INITIAL INTENSITY IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE SUBJECTIVE DVORAK ESTIMATES RANGING BETWEEN 30-35 KNOTS. INITIAL WIND RADII BASIS: OBJECTIVE BEST TRACK CURRENT STEERING MECHANISM: SUBTROPICAL RIDGE (STR) TO THE SOUTHEAST LOCATED OVER CENTRAL AUSTRALIA AND EXTENDING WESTWARD INTO THE SOUTHWESTERN INDIAN OCEAN. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T2.5 - 35 KTS KNES: T2.5 - 35 KTS DEMS: T2.5 - 35 KTS APRF: T2.0 - 30 KTS CIMSS ADT: 33 KTS AT 150820Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINALLY FAVORABLE VWS: 15-20 KTS SST: 29-30 CELSIUS OUTFLOW: MODERATE RADIAL 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 WEST-SOUTHWESTWARD ALONG THE NORTHWESTERN PERIPHERY OF THE STR LOCATED OVER CENTRAL AUSTRALIA AND EXTENDING WESTWARD INTO THE SOUTHWESTERN INDIAN OCEAN (IO). AS THE AFOREMENTIONED DEEP-LAYER STR CONTINUES TO BUILD SLIGHTLY WESTWARD, TC 18S IS FORECASTED TO CONTINUE ITS SLOW, MEANDERING WEST- SOUTHWESTWARD TRACK THROUGH TAU 36. AFTER TAU 36, A DEEP LONGWAVE TROUGH WILL WEAKEN THE STR STEERING FLOW, ALLOWING FOR A SHARP SOUTHWESTWARD TRACK UNTIL TAU 72. AS THE HIGH IN THE SOUTHERN IO REORIENTS EASTWARD, TC 18S WILL BEGIN A WEST-NORTHWESTWARD TRACK ALONG THE NORTHERN PERIPHERY OF THE SOUTHEAST TRADE FLOW THROUGH TAU 120. AS THE CYCLONE PROGRESSES GENERALLY WESTWARD, A MORE CONDUCIVE ENVIRONMENT IS EXPECTED AS VERTICAL WIND SHEAR (VWS) REMAINS LOW (10- 15 KNOTS), THE SYSTEM'S CORE MAINTAINS ITS MOIST STRUCTURE, AND FAVORABLE POLEWARD OUTFLOW INCREASES, RESULTING IN A STEADY INCREASE IN INTENSITY THROUGH TAU 120 OF UP TO 65 KNOTS. MODEL DISCUSSION: THE DETERMINISTIC MODEL TRACK GUIDANCE IS IN POOR AGREEMENT THROUGH TAU 72, AS THE NAVGEM AND GFS TRACKERS HAVE ILLUSTRATED ERRATIC FORECAST SOLUTIONS OVER THE LAST 12 HOURS AWAY FROM THE CONSENSUS. THE 150600Z ECMWF ENSEMBLE (EPS) AND GFS ENSEMBLE (GEFS) ALSO INDICATE CONTINUED UNCERTAINTY AFTER TAU 72 DUE TO COMPETING STEERING MECHANISMS, WITH TWO DISTINCT GROUPINGS OF SOLUTIONS IN A SOUTHWARD AND WESTWARD TRAJECTORY. ROUGHLY 90 PERCENT OF THE EPS AND GEFS SOLUTIONS DEPICT A GENERAL WESTWARD TRACK, WHILE 10 PERCENT OF ENSEMBLE SOLUTIONS HAVE SHOWN A SLOW SOUTHWARD TRACK INTO NORTHWESTERN AUSTRALIA. THE 150600Z COAMPS-TC INTENSITY ENSEMBLE (CTCXEPS) SHOWS A STEADY INTENSIFICATION TREND, WITH DECREASING PEAK PROBABILITIES REACHING MODERATE INTENSIFICATION OF 30 TO 40 PERCENT BETWEEN TAU 60 AND TAU 84. 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 151927 IDW27600 TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE at: 1927 UTC 15/03/2024 Name: Tropical Low Identifier: 08U Data At: 1800 UTC Latitude: 17.7S Longitude: 115.0E Location Accuracy: within 45nm (85 km) Movement Towards: southwest (235 deg) Speed of Movement: 2 knots (3 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: T1.5/2.0/S0.0/24HRS 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: 16/0000: 17.7S 114.9E: 060 (110): 030 (055): 995 +12: 16/0600: 17.7S 114.7E: 070 (130): 030 (055): 996 +18: 16/1200: 17.7S 114.5E: 075 (140): 030 (055): 996 +24: 16/1800: 17.6S 114.3E: 080 (145): 030 (055): 996 +36: 17/0600: 17.7S 114.0E: 090 (165): 030 (055): 996 +48: 17/1800: 18.1S 113.8E: 110 (205): 030 (055): 997 +60: 18/0600: 18.6S 113.3E: 130 (245): 035 (065): 993 +72: 18/1800: 18.8S 112.9E: 155 (285): 040 (075): 989 +96: 19/1800: 18.4S 111.6E: 205 (380): 045 (085): 987 +120: 20/1800: 18.2S 108.9E: 260 (485): 040 (075): 991 REMARKS: The low level centre is not clear in IR imagery and is insufficiently defined in microwave to give confidence in the position. IR imagery suggests moderate to high shear continues in accordance with the CIMSS shear analyses. Intensity is set at 30 knots. Dvorak analysis: Shear pattern has the LLC more than 1.25 degrees from deep convection, so not used. MET/PAT give 1.0. FT is restricted to 1.5, CI is held to 2.0. Recent objective guidance: ADT 33kn, AiDT 30kn, DPRINT 35kn (1800 UTC, both 1-min average). The low level circulation remains convection free. Thunderstorm activity to the west has lightning, indicating dry air. 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. Upper level winds are forecast to become supportive of poleward outflow, with some indications in imagery and AMVs that this is already happening. The reduction in deep layer wind shear may allow the system to begin to slowly strengthen from later Saturday or Sunday, and tropical cyclone strength is currently forecast from Tuesday. Further intensification is possible as 08U tracks west or southwest under the influence of the ridge. Some guidance has it maintaining tropical cyclone intensity or intensifying further mid to late next week, however this is questionable given the dry surrounding environment. The most likely track scenario is for 08U to remain off the Western Australian coast as it moves slowly west or southwest. There is a small chance of it becoming near stationary over the weekend then moving south early next week, taking it close to or across the western Pilbara coast. Copyright Commonwealth of Australia == The next bulletin for this system will be issued by: 16/0130 UTC.
Time (AWST) Intensity Category Latitude
(decimal deg.)Longitude
(decimal deg.)Estimated Position
Accuracy (km)0hr 2 am March 16 tropical low 17.7S 115.0E 85 +6hr 8 am March 16 tropical low 17.7S 114.9E 110 +12hr 2 pm March 16 tropical low 17.7S 114.7E 130 +18hr 8 pm March 16 tropical low 17.7S 114.5E 140 +24hr 2 am March 17 tropical low 17.6S 114.3E 145 +36hr 2 pm March 17 tropical low 17.7S 114.0E 165 +48hr 2 am March 18 tropical low 18.1S 113.8E 205 +60hr 2 pm March 18 tropical low 18.6S 113.3E 245 +72hr 2 am March 19 1 18.8S 112.9E 285 -
WTXS32 PGTW 152100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 019// RMKS/ 1. TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 019 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 151800Z --- NEAR 17.8S 114.8E MOVEMENT PAST SIX HOURS - 205 DEGREES AT 02 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 - 030 NM NORTHEAST QUADRANT 065 NM SOUTHEAST QUADRANT 065 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT REPEAT POSIT: 17.8S 114.8E --- FORECASTS: 12 HRS, VALID AT: 160600Z --- 17.8S 114.4E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 020 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 300 DEG/ 01 KTS --- 24 HRS, VALID AT: 161800Z --- 17.7S 114.2E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 020 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 270 DEG/ 01 KTS --- 36 HRS, VALID AT: 170600Z --- 17.7S 114.0E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 010 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 020 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 195 DEG/ 02 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 171800Z --- 18.1S 113.9E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 000 NM SOUTHWEST QUADRANT 010 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 215 DEG/ 01 KTS --- 72 HRS, VALID AT: 181800Z --- 18.5S 113.6E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 080 NM SOUTHEAST QUADRANT 080 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 295 DEG/ 04 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 191800Z --- 17.9S 112.2E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 040 NM NORTHEAST QUADRANT 080 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT VECTOR TO 120 HR POSIT: 275 DEG/ 04 KTS --- 120 HRS, VALID AT: 201800Z --- 17.8S 110.7E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT 100 NM SOUTHEAST QUADRANT 100 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT --- REMARKS: 152100Z POSITION NEAR 17.8S 114.7E. 15MAR24. TROPICAL CYCLONE 18S (EIGHTEEN), LOCATED APPROXIMATELY 273 NM NORTH OF LEARMONTH, AUSTRALIA, HAS TRACKED SOUTH-SOUTHWESTWARD AT 02 KNOTS OVER THE PAST SIX HOURS. MINIMUM CENTRAL PRESSURE AT 151800Z IS 997 MB. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 151800Z IS 16 FEET. NEXT WARNINGS AT 160300Z, 160900Z, 161500Z AND 162100Z. // NNNN
WDXS32 PGTW 152100 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 019// 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: SOUTH-SOUTHWESTWARD AT 02 KTS SIGNIFICANT WAVE HEIGHT: 16 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED ENHANCED INFRARED (EIR) SATELLITE IMAGERY DEPICTS A PARTIALLY OBSCURED LOW LEVEL CIRCULATION CENTER (LLCC) WITH FLARING DEEP CONVECTION DISPLACED WEST OF THE CENTER DUE TO ELEVATED EASTERLY VERTICAL WIND SHEAR (VWS) BETWEEN 25-30KTS. MODERATE POLEWARD OUTFLOW IS EVIDENCED BY EXPANDING CIRRUS FILAMENTS EXTENDING WEST SOUTHWEST OF THE CENTER. ON THE LOWER LEVELS, BANDING CLOUDS WRAP INTO THE LLCC INDICATING A MOIST ENVIRONMENT SUPPORTED BY WARM SEA SURFACE TEMPERATURES OF 28-29C. CURRENTLY, TROPICAL CYCLONE (TC) 18S IS IN A COMPETING STEERING ENVIRONMENT ON THE LOWER LEVELS WITH A LOW- TO MID-LEVEL STR OVER SOUTHWESTERN AUSTRALIA AND THE SOUTHERN PERIPHERY OF A NEAR EQUATORIAL RIDGE (NER) TO THE NORTH. THE INITIAL POSITION WAS ASSESSED USING ANIMATED EIR IMAGERY IDENTIFYING THE EXPOSED LLCC. HOWEVER, THE POTENTIAL FOR A POSSIBLE SECONDARY CIRCULATION CENTER CANNOT BE RULED OUT UNDERNEATH THE DEEP LAYER CONVECTION THAT MAY NOT BE IDENTIFIED ON THE LOWER LEVELS DUE TO THE USE OF EIR. THE INITIAL INTENSITY WAS ASSESSED USING PERSISTENCE AND THE AGENCY AND OBJECTIVE FIXES LISTED BELOW. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: IN A COMPETING STEERING ENVIRONMENT ON THE NORTHWESTERN PERIPHERY RIDGE TO THE SOUTHEAST AND THE SOUTHERN PERIPHERY OF AN NER TO THE NORTH. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T2.5 - 35 KTS KNES: T2.5 - 35 KTS APRF: T1.5 - 25 KTS CIMSS ADT: 33 KTS AT 151730Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE VWS: 25-30 KTS SST: 29-30 CELSIUS OUTFLOW: MODERATE POLEWARD ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: HIGH 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 REMAIN QUASI-STATIONARY OVER THE NEXT 36 HOURS AS IT REMAINS TRAPPED IN A WEAK STEERING ENVIRONMENT. AS A RIDGE OVER SOUTHWESTERN AUSTRALIA TRAVELS WEST, A REGION OF WEAKNESS WILL REMAIN OVER THE WESTERN EXPANSE OF AUSTRALIA THROUGH THE 36 HOUR POINT, AND TC 18S IS FORECAST TO DRIFT GENERALLY SOUTHWARD BETWEEN TAU 24 AND 48. BY TAU 48, A STRONG LOW- TO MID-LEVEL STR IS EXPECTED TO DEVELOP AND BUILD OVER SOUTHWESTERN AUSTRALIA, DRIVING TC 18S ONTO A WESTWARD TRACK FROM TAU 72 THROUGH THE END OF THE FORECAST PERIOD. THERE IS SIGNIFICANT VARIATION IN HOW THE SYSTEM MAY MOVE WITHIN THE WEAK STEERING ENVIRONMENT IN THE FIRST 48 HOURS, MEANING THAT A SLIGHT EASTWARD, SOUTHWARD, OR WESTWARD TRACK ARE ALL POSSIBLITIES AT A SLOW TRACK SPEED BEFORE TAKING OFF TO THE WEST AT TAU 72. THE INTENSITY FOR THE TC18S IS FORECAST TO REMAIN STEADY FOR THE 48 HOURS DUE TO ELEVATED VWS OF 25-30KTS AND MINIMAL UPPER-LEVEL DIVERGENCE TO SUPPORT OUTFLOW. ONCE THE SYSTEM BEGINS TO TAP INTO THE JET MAXIMUM TO THE SOUTH, TC 18S MAY BEGIN TO DEVELOP A OUTFLOW CHANNEL BETWEEN TAU 48-60, AT WHICH POINT THE CYCLONE IS ANTICIPATED TO GRADUALLY INTENSIFY TO A MAXIMUM OF 45KTS. MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN SIGNIFICANT DISAGREEMENT AS TO THE INITIAL TRACK THAT TC 18S WILL INITIALLY TAKE DUE TO THE HIGHLY WEAK STEERING ENVIRONMENT THAT PERSISTS. GFS INITIALLY TAKES THE SYSTEM ON A NORTHEAST AND THEN SOUTHEAST TRACK FOR THE FIRST 72 HOURS BEFORE SHARPLY TURNING NORTHEAST AGAIN AND SUDDENLY SOUTHWEST BETWEEN TAUS 72-96 AND CONTINUING THROUGH THE END OF THE FORECAST PERIOD. ECMWF, ON THE OTHER HAND, TAKES THE SYSTEM TO THE WEST-NORTHWEST FOR THE FIRST 24 HOURS AND THEN SHARPLY SOUTH-SOUTHWEST THROUGH TAU 72 BEFORE CONTINUING AGAIN TO THE WEST-NORTHWEST THROUGH THE END OF THE FORECAST PERIOD. THE SHARP VARIATIONS IN TRACK INDICATED A POSSIBLE ELONGATED QUASI-STATIONARY PERIOD BEFORE PICKING UP AND TRACKING WESTWARD. THE JTWC INTENSITY CONSENSUS GUIDANCE IS SPLIT BETWEEN BOTH GFS AND NAVGEM BASED SHIPS GUIDANCE, HWRF, AND HAFS-A ANTICIPATING SIGNIFICANT INTENSIFICATION THROUGHOUT THE FORECAST PERIOD AND COAMPS-TC AND GFS INDICATING STAGNATION, EVEN POSSIBLE WEAKENING BE THE END OF THE FORECAST. THE INTENSITY FORECAST REFLECTS THE MOST LIKELY STAGNANT RATE OF INTENSIFICATION OVER THE NEXT 36-60 HOURS, BUT ALSO THE POTENTIAL FOR INTENSIFICATION AS OUTFLOW IMPROVES AT THE 48-60 HOUR MARK. 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 2024-03-16 06:00:00 被ygsj24编辑 ，原因： -
AXAU01 APRF 160051 IDW27600 TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE at: 0051 UTC 16/03/2024 Name: Tropical Low Identifier: 08U Data At: 0000 UTC Latitude: 17.4S Longitude: 114.7E Location Accuracy: within 45nm (85 km) Movement Towards: west northwest (300 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: 998 hPa Radius of 34-knot winds NE quadrant: Radius of 34-knot winds SE quadrant: Radius of 34-knot winds SW quadrant: Radius of 34-knot winds NW quadrant: Radius of 48-knot winds NE quadrant: Radius of 48-knot winds SE quadrant: Radius of 48-knot winds SW quadrant: Radius of 48-knot winds NW quadrant: Radius of 64-knot winds: nm ( km) Radius of Maximum Winds: nm ( km) Dvorak Intensity Code: T1.0/2.0/W1.0/24HRS STT:W0.5/06HRS Pressure of outermost isobar: 1004 hPa Radius of outermost closed isobar: 240 nm (445 km) FORECAST DATA Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure (UTC) : degrees : nm (km): knots(km/h): hPa +06: 16/0600: 17.4S 114.6E: 060 (110): 030 (055): 998 +12: 16/1200: 17.4S 114.4E: 070 (125): 030 (055): 998 +18: 16/1800: 17.4S 114.2E: 070 (135): 030 (055): 998 +24: 17/0000: 17.5S 114.1E: 075 (140): 030 (055): 998 +36: 17/1200: 17.6S 113.9E: 080 (150): 030 (055): 997 +48: 18/0000: 17.7S 113.7E: 105 (190): 030 (055): 997 +60: 18/1200: 17.9S 113.5E: 115 (215): 030 (055): 997 +72: 19/0000: 18.0S 113.3E: 135 (255): 030 (055): 997 +96: 20/0000: 17.6S 112.2E: 165 (300): 045 (085): 990 +120: 21/0000: 17.8S 109.7E: 205 (375): 040 (075): 994 REMARKS: The low level centre is not clear in IR imagery and is insufficiently defined in microwave to give confidence in the position. IR imagery suggests moderate to high shear continues in accordance with the CIMSS shear analyses. Intensity is set at 30 knots. Dvorak analysis: DT is not clear, the system is under shear but there has been some recent convection closer to the centre. A curved band with a warp of 0.1 is possible, regardless this wasn't used. MET/PAT give 1.0. FT is 1.0, CI is held to 1.5. Recent objective guidance: ADT 35kn, AiDT 33kn, DPRINT 29kn (1800 UTC, both 1-min average). Intensity is set at 30kn (10-min mean) and based on persistence with support from the objective aids and Dvorak. There has been some recent convection near the low level centre, however this does not look persistent and rather is fluctuating. Thunderstorm activity to the west has lightning, indicating dry air. Environmental conditions are otherwise somewhat favourable with SSTs 28-29C along track. Shear is expected to ease and become more northerly from later Sunday. Upper level winds are forecast to become supportive of poleward outflow, with some indications in imagery that this is already happening. The reduction in deep layer wind shear may allow the system to begin to slowly strengthen from Monday, and tropical cyclone strength is currently forecast from Tuesday evening. Further intensification is possible as 08U tracks west or southwest under the influence of the ridge. Some guidance has it maintaining tropical cyclone intensity or intensifying further mid to late next week, however this is questionable given the dry surrounding environment. The most likely track scenario is for 08U to remain off the Western Australian coast as it moves slowly west or southwest. Copyright Commonwealth of Australia == The next bulletin for this system will be issued by: 16/0730 UTC.
Time (AWST) Intensity Category Latitude
(decimal deg.)Longitude
(decimal deg.)Estimated Position
Accuracy (km)0hr 8 am March 16 tropical low 17.4S 114.7E 85 +6hr 2 pm March 16 tropical low 17.4S 114.6E 110 +12hr 8 pm March 16 tropical low 17.4S 114.4E 125 +18hr 2 am March 17 tropical low 17.4S 114.2E 135 +24hr 8 am March 17 tropical low 17.5S 114.1E 140 +36hr 8 pm March 17 tropical low 17.6S 113.9E 150 +48hr 8 am March 18 tropical low 17.7S 113.7E 190 +60hr 8 pm March 18 tropical low 17.9S 113.5E 215 +72hr 8 am March 19 tropical low 18.0S 113.3E 255 -
WTXS32 PGTW 160300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 020// RMKS/ 1. TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 020 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 160000Z --- NEAR 17.5S 114.5E MOVEMENT PAST SIX HOURS - 315 DEGREES AT 04 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 - 030 NM NORTHEAST QUADRANT 065 NM SOUTHEAST QUADRANT 065 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT REPEAT POSIT: 17.5S 114.5E --- FORECASTS: 12 HRS, VALID AT: 161200Z --- 17.4S 114.3E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 020 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 010 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 270 DEG/ 01 KTS --- 24 HRS, VALID AT: 170000Z --- 17.4S 114.0E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 020 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 010 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 225 DEG/ 01 KTS --- 36 HRS, VALID AT: 171200Z --- 17.6S 113.8E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT 080 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 210 DEG/ 02 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 180000Z --- 17.9S 113.6E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT 090 NM SOUTHEAST QUADRANT 080 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 260 DEG/ 01 KTS --- 72 HRS, VALID AT: 190000Z --- 18.0S 113.0E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT 090 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 280 DEG/ 03 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 200000Z --- 17.8S 111.7E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT 090 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT VECTOR TO 120 HR POSIT: 280 DEG/ 03 KTS --- 120 HRS, VALID AT: 210000Z --- 17.6S 110.3E MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT 110 NM SOUTHEAST QUADRANT 110 NM SOUTHWEST QUADRANT 100 NM NORTHWEST QUADRANT --- REMARKS: 160300Z POSITION NEAR 17.5S 114.5E. 16MAR24. TROPICAL CYCLONE 18S (EIGHTEEN), LOCATED APPROXIMATELY 289 NM NORTH OF LEARMONTH, AUSTRALIA, HAS TRACKED NORTHWESTWARD AT 04 KNOTS OVER THE PAST SIX HOURS. MINIMUM CENTRAL PRESSURE AT 160000Z IS 1001 MB. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 160000Z IS 16 FEET. NEXT WARNINGS AT 161500Z AND 170300Z. // NNNN
WDXS32 PGTW 160300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 020// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 17.5S 114.5E INITIAL INTENSITY: 35 KTS GEOGRAPHIC REFERENCE: 289 NM NORTH OF LEARMONTH, AUSTRALIA MOVEMENT PAST 6 HOURS: NORTHWESTWARD AT 04 KTS SIGNIFICANT WAVE HEIGHT: 16 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS A PARTIALLY EXPOSED LOW LEVEL CIRCULATION CENTER OBSCURED BY FLARING CONVECTION OFFSET TO THE WEST. LOW-LEVEL CLOUD BANDING IS ALSO VISIBLE WRAPPING INTO THE CIRCULATION CENTER. THE WESTWARD VERTICAL TILT WITH HEIGHT CAN BE ATTRIBUTED TO A TIGHT GRADIENT OF ELEVATED VERTICAL WIND SHEAR (VWS) OF 20-25KTS, COUPLED WITH DRY AIR ENTRAINMENT INTO THE SYSTEM FROM THE NORTHWEST CREATING AN UNFAVORABLE ENVIRONMENT FOR INTENSIFICATION. MODERATE WEST-SOUTHWESTWARD OUTFLOW AND FAVORABLE SEA SURFACE TEMPERATURES SUPPORT THE STAGNANT NATURE OF THE SYSTEM. CURRENTLY TROPICAL CYCLONE (TC) 18S IS DRIFTING NORTHWESTWARD IN A COMPETING STEERING ENVIRONMENT IN THE LOWER-LEVELS WHILE RIDING THE SOUTHERN PERIPHERY OF A NEAR EQUATORIAL RIDGE (NER) TO THE NORTH AND THE NORTHWESTERN PERIPHERY OF A SUBTROPICAL RIDGE (STR) TO THE SOUTHEAST. THE INITIAL POSITION WAS ASSESSED WITH HIGH CONFIDENCE BASED ON ANIMATED MSI AND A 162205Z 37GHZ SSMIS MICROWAVE IMAGE REVEALING A LLCC. THE INITIAL INTENSITY WAS ASSESSED WITH LOW CONFIDENCE BASED ON PERSISTENCE AND AGENCY AND OBJECTIVE FIXES LISTED BELOW. INITIAL WIND RADII BASIS: PERSISTENCE CURRENT STEERING MECHANISM: COMPETING STEERING ENVIRONMENT. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T2.5 - 35 KTS KNES: T2.5 - 35 KTS APRF: T1.0 - 25 KTS CIMSS ADT: 35 KTS AT 152330Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: UNFAVORABLE VWS: 20-25 KTS SST: 28-29 CELSIUS OUTFLOW: MODERATE POLEWARD 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 DRIFT WESTWARD FOR THE NEXT 36 HOURS BEFORE SLOWLY CURVING TO THE WEST-SOUTHWEST FROM TAU 36-48 AS THE RIDGE TO THE SOUTHEAST OVER AUSTRALIA WEAKENS. BY HOUR 72, THE SYSTEM IS DRIVEN WESTWARD BY A SUBTROPICAL RIDGE THAT BUILDS BETWEEN TAU 60-72 THAT WILL CARRY TC 18S THROUGH TO THE END OF THE FORECAST PERIOD. GIVEN THE WEAK NATURE OF THE STEERING ENVIRONMENT UNTIL TAU 48, THE POTENTIAL CANNOT BE RULED OUT THAT THE SYSTEM MAY DRIFT IN ANY DIRECTION BEFORE BEING DRIVEN WESTWARD. THE INTENSITY FORECAST HAS CHANGED SLIGHTLY OVER THE LAST SIX HOURS, REMAINING STAGNANT AT 35KTS FOR THE FIRST 24 HOURS BEFORE SLIGHTLY INTENSIFYING FROM TAU 24-48 AS THE VWS MODERATES AND THE UPPER-LEVEL ENVIRONMENT FAILS TO SUPPORT SIGNIFICANT OUTFLOW. UNTIL TAU 96, THE SYSTEM IS EXPECTED TO STRUGGLE TO INTENSIFY AGAINST THE MODERATE VWS UNTIL POTENTIALLY TAPPING INTO A JET MAXIMUM TO THE SOUTH THAT MAY CREATE A STRONG POLEWARD CHANNEL SUPPORTING MODEST INTENSIFICATION. MODEL DISCUSSION: DETERMINISTIC MODEL GUIDANCE IS IN POOR AGREEMENT AS TO THE INITIAL DIRECTION AS HOW TC 18S WILL DRIFT THROUGH THE FIRST 48-72 HOURS. GFS AND AEMI INITIALLY DRIFT EAST FOR THE FIRST 24 HOURS AND THEN SOUTHEAST THROUGH TAU 60 BEFORE BEING PICKED UP BY THE BUILDING STR TO THE SOUTHEAST AND TRAVELING WEST. THE ECMWF AND ENSEMBLE GUIDANCE INDICATE A SLOW DRIFT WESTWARD BEFORE DIVING SOUTH THROUGH TAU 48 AND WEST AT TAU 72 WHEN PICKED UP BY A SOUTHERN STR. JTWC INTENSITY GUIDANCE ALSO IS IN POOR AGREEMENT WITH A OVERALL 150KT SPREAD BETWEEN HAFS-A WHICH HAS A PEAK OF 175KTS AND COAMPS-TC WHICH ANTICIPATES A WEAKENING TO 25KTS BY TAU 120. THE JTWC INTENSITY FORECAST IS ASSESSED WITH LOW CONFIDENCE ACKNOWLEDGING THE POTENTIAL FOR NEAR STAGNATION THROUGH THE FIRST 48 HOURS AT 35KTS AND A SLOW INCREASE TO 45KTS BY TAU 96. BOTH ECMWF AND GFS AGREE THAT THE ENVIRONMENT FOR UPPER-LEVEL DIVERGENCE AND OUTFLOW WILL BECOME MORE FAVORABLE BEYOND TAU 96. 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 2024-03-16 13:00:00 被ygsj24编辑 ，原因： -
AXAU01 APRF 160659 IDW27600 TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE at: 0659 UTC 16/03/2024 Name: Tropical Low Identifier: 08U Data At: 0600 UTC Latitude: 17.3S Longitude: 114.1E Location Accuracy: within 25nm (45 km) Movement Towards: west northwest (290 deg) Speed of Movement: 5 knots (9 km/h) Maximum 10-Minute Wind: 30 knots (55 km/h) Maximum 3-Second Wind Gust: 45 knots (85 km/h) Central Pressure: 999 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: T1.0/1.5/W1.0/24HRS STT:S0.0/06HRS Pressure of outermost isobar: 1004 hPa Radius of outermost closed isobar: 220 nm (405 km) FORECAST DATA Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure (UTC) : degrees : nm (km): knots(km/h): hPa +06: 16/1200: 17.3S 114.0E: 055 (100): 030 (055): 998 +12: 16/1800: 17.2S 113.9E: 060 (115): 030 (055): 998 +18: 17/0000: 17.2S 113.8E: 065 (120): 030 (055): 998 +24: 17/0600: 17.3S 113.7E: 070 (130): 030 (055): 998 +36: 17/1800: 17.6S 113.4E: 075 (140): 030 (055): 998 +48: 18/0600: 17.8S 113.2E: 100 (185): 030 (055): 998 +60: 18/1800: 17.9S 113.0E: 110 (205): 030 (055): 998 +72: 19/0600: 17.6S 112.7E: 130 (245): 030 (055): 995 +96: 20/0600: 17.0S 110.9E: 155 (290): 035 (065): 990 +120: 21/0600: 17.1S 108.0E: 190 (355): 045 (085): 994 REMARKS: Tropical low 08U continues to struggle to develop. Intensity is set at 30 knots with ASCAT imagery at 0210 UTC indicating 30 kn to the north of the centre. The centre analysis is fair with the ASCAT pass and visible Himawari satellite imagery. Convection is to the west of the low level centre in accordance with the CIMSS shear analyses. Dvorak analysis: DT is not clear. A curved band with a wrap of 0.2 is possible, regardless this wasn't used. With a 24hr W trend MET/PAT yields 1.0. FT is 1.0, CI is held to 1.5. Recent objective guidance: ADT 51kn, AiDT 42kn, DPRINT 32kn (0600 UTC, both 1-min average). Objective aides have tended to be higher than scatterometry would suggest, intensity is heavily biased to scatterometry. Convection continues to fluctuate, at this time there is limited deep convection. Environmental conditions are somewhat favourable with SSTs 28-29C along track. The easterly shear that is currently impacting the circulation is expected to ease and become more northerly this evening. With an upper trough approaching from the southwest the upper level winds are forecast to become supportive of poleward outflow, more likely from Sunday or Monday. The reduction in deep layer wind shear may allow the system to begin to slowly strengthen from Monday, and tropical cyclone strength is currently forecast from Wednesday. Further intensification is possible as 08U tracks west or southwest under the influence of the ridge. Some guidance has it maintaining tropical cyclone intensity or intensifying further mid to late next week, however this is questionable given the dry surrounding environment. The most likely track scenario is for 08U to remain off the Western Australian coast as it moves slowly west or southwest. Copyright Commonwealth of Australia == The next bulletin for this system will be issued by: 16/1330 UTC.
Time (AWST) Intensity Category Latitude
(decimal deg.)Longitude
(decimal deg.)Estimated Position
Accuracy (km)0hr 2 pm March 16 tropical low 17.3S 114.1E 45 +6hr 8 pm March 16 tropical low 17.3S 114.0E 100 +12hr 2 am March 17 tropical low 17.2S 113.9E 115 +18hr 8 am March 17 tropical low 17.2S 113.8E 120 +24hr 2 pm March 17 tropical low 17.3S 113.7E 130 +36hr 2 am March 18 tropical low 17.6S 113.4E 140 +48hr 2 pm March 18 tropical low 17.8S 113.2E 185 +60hr 2 am March 19 tropical low 17.9S 113.0E 205 +72hr 2 pm March 19 tropical low 17.6S 112.7E 245 -
WTXS32 PGTW 160900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 021// RMKS/ 1. TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 021 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 160600Z --- NEAR 17.3S 114.0E MOVEMENT PAST SIX HOURS - 290 DEGREES AT 03 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 - 055 NM NORTHEAST QUADRANT 055 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT REPEAT POSIT: 17.3S 114.0E --- FORECASTS: 12 HRS, VALID AT: 161800Z --- 17.3S 113.8E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT 050 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 090 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 250 DEG/ 02 KTS --- 24 HRS, VALID AT: 170600Z --- 17.4S 113.5E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT 090 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 205 DEG/ 01 KTS --- 36 HRS, VALID AT: 171800Z --- 17.6S 113.4E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 090 NM SOUTHEAST QUADRANT 080 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 200 DEG/ 02 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 180600Z --- 17.9S 113.3E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 090 NM SOUTHEAST QUADRANT 080 NM SOUTHWEST QUADRANT 070 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 270 DEG/ 01 KTS --- 72 HRS, VALID AT: 190600Z --- 17.9S 113.0E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 090 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 285 DEG/ 04 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 200600Z --- 17.5S 111.3E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT 080 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 100 NM NORTHWEST QUADRANT VECTOR TO 120 HR POSIT: 270 DEG/ 05 KTS --- 120 HRS, VALID AT: 210600Z --- 17.4S 109.0E MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 040 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 090 NM NORTHEAST QUADRANT 080 NM SOUTHEAST QUADRANT 090 NM SOUTHWEST QUADRANT 110 NM NORTHWEST QUADRANT --- REMARKS: 160900Z POSITION NEAR 17.3S 114.0E. 16MAR24. TROPICAL CYCLONE 18S (EIGHTEEN), LOCATED APPROXIMATELY 300 NM NORTH OF LEARMONTH, AUSTRALIA, HAS TRACKED WEST- NORTHWESTWARD AT 03 KNOTS OVER THE PAST SIX HOURS. MINIMUM CENTRAL PRESSURE AT 160600Z IS 998 MB. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 160600Z IS 15 FEET. NEXT WARNINGS AT 161500Z, 162100Z, 170300Z AND 170900Z.// NNNN
WDXS32 PGTW 160900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 021// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 17.3S 114.0E INITIAL INTENSITY: 35 KTS GEOGRAPHIC REFERENCE: 300 NM NORTH OF LEARMONTH, AUSTRALIA MOVEMENT PAST 6 HOURS: WEST-NORTHWESTWARD AT 03 KTS SIGNIFICANT WAVE HEIGHT: 15 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) DEPICTS TROPICAL CYCLONE (TC) 18S (EIGHTEEN) WITH A WEAKENING CONVECTIVE STRUCTURE THAT IS OFFSET TO THE WEST OF A POORLY ORGANIZED LOW-LEVEL CIRCULATION CENTER (LLCC). A 160210Z ASCAT-B IMAGE REVEALS WINDS OF 25-30 KTS IN THE NORTHERN SEMICIRCLE. ENVIRONMENTAL ANALYSIS INDICATES THAT 18S IS IN A MARGINAL ENVIRONMENT FOR INTENSIFICATION WITH MODERATE WESTWARD OUTFLOW ALOFT, LOW TO MODERATE (15-20 KTS) EASTERLY VERTICAL WIND SHEAR, AND WARM (28-29 C) SEA SURFACE TEMPERATURES. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON THE DISORGANIZED PARTIALLY EXPOSED LLCC OBSERVABLE IN ANIMATED MSI. THE INITIAL INTENSITY OF 35 KTS IS ASSESSED WITH MEDIUM CONFIDENCE BASED ON THE OBJECTIVE AND SUBJECTIVE INTENSITY ESTIMATES LISTED BELOW. INITIAL WIND RADII BASIS: SCATTEROMETER DATA CURRENT STEERING MECHANISM: COMPETING STEERING ENVIRONMENT. AGENCY DVORAK AND AUTOMATED FIXES: PGTW: T2.0 - 30 KTS KNES: T2.0 - 30 KTS DEMS: T2.5 - 35 KTS CIMSS AIDT: 42 KTS AT 160600Z CIMSS DPRINT: 32 KTS AT 160600Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL VWS: 15-20 KTS SST: 28-29 CELSIUS OUTFLOW: MODERATE 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 CURRENTLY TRACKING SLOWLY WEST-NORTHWESTWARD WHILE LOCATED WITHIN A COMPETING STEERING ENVIRONMENT. A NEAR EQUATORIAL RIDGE TO THE NORTH AND A SUBTROPICAL RIDGE TO THE SOUTH ARE CAUSING THE SYSTEM TO DRIFT SLOWLY IN A QUASI- STATIONARY FASHION. TC 18S IS FORECAST TO MAINTAIN A WEAK STEERING MECHANISM OVER THE NEXT 60-72 HOURS. DURING THIS TIME THERE IS A VARIETY OF DIFFERENT TRACKS THE SYSTEM COULD TAKE, AND THE MODEL GUIDANCE SUGGESTS THAT. TC 18S IS FORECAST TO TRACK SLOWLY WESTWARD UNTIL TAU 24. AFTER TAU 24, TC 18S IS FORECAST TO TURN SOUTH- SOUTHWEST, STILL VERY SLOWLY UNTIL TAU 48. AFTER TAU 60, THE STEERING MECHANISM WILL BE MORE DEFINED, AND THE SYSTEM IS EXPECTED TO TRACK WESTWARD ALONG THE NORTHERN PERIPHERY OF A SUBTROPICAL RIDGE (STR) FOR THE REMAINDER OF THE FORECAST PERIOD. REGARDING INTENSITY, THE JTWC INTENSITY FORECASTS HAS TC 18S SLOWLY INTENSIFYING TO 45 KTS AT TAU 48, MAINLY DUE TO IMPROVING DIVERGENCE ALOFT AROUND THAT TIME. TC 18S IS FORECAST TO MAINTAIN 45 KTS THROUGH TAU 96 AS THE SYSTEM CONTINUES TO EXPERIENCE 15-20 KT VERTICAL WIND SHEAR AND LOW OCEAN HEAT CONTENT, INCREASING TO NEAR 50 KTS BY TAU 120. MODEL DISCUSSION: NUMERICAL MODEL GUIDANCE IS IN RELATIVELY POOR AGREEMENT, AS IS SOMEWHAT EXPECTED DUE TO THE COMPETING STEERING MECHANISM, AND AS SUCH IS ASSESSED WITH OVERALL LOW CONFIDENCE. GFS AND NAVGEM DIFFER FROM THE REST OF THE GUIDANCE CONSIDERABLY. THEY TRACK THE SYSTEM SOUTHWARD OVER THE FIRST 48 HOURS, AND GFS TRACKS IT BACK NORTHWARD UNTIL TAU 96 BEFORE MAKING THE WESTWARD TURN. THE JTWC TRACK FORECAST FOLLOWS MORE CLOSELY WITH THE REST OF THE GUIDANCE, THAT HAS THE SYSTEM FOLLOWING A TRACK IN A SIMILAR WAY AS DESCRIBED ABOVE IN THE FORECAST DISCUSSION. THE JTWC INTENSITY FORECAST IS ALSO ASSESSED WITH LOW CONFIDENCE BASED ON THE SPREAD IN GUIDANCE. COAMPS-TC HAS THE SYSTEM REACHING A PEAK OF 45 KTS AT TAU 48, THEN WEAKENING AFTERWARD. HAFS-A AND HWRF BOTH HAVE THE SYSTEM QUICKLY INTENSIFYING AFTER TAU 60 WITH HWRF ATTAINING 90 KTS AT TAU 108 AND HAFS-A ATTAINING 95 KTS AT TAU 120. THE JTWC INTENSITY FORECAST MOST CLOSELY FOLLOWS THE CONSENSUS MEAN AND IS ASSESSED WITH OVERALL LOW CONFIDENCE DUE TO THE VARIABILITY IN MODEL 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 2024-03-16 20:00:00 被ygsj24编辑 ，原因： -
AXAU01 APRF 161300 IDW27600 TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE at: 1300 UTC 16/03/2024 Name: Tropical Low Identifier: 08U Data At: 1200 UTC Latitude: 17.5S Longitude: 113.9E Location Accuracy: within 40nm (75 km) Movement Towards: west southwest (245 deg) Speed of Movement: 3 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: 998 hPa Radius of 34-knot winds NE quadrant: Radius of 34-knot winds SE quadrant: Radius of 34-knot winds SW quadrant: Radius of 34-knot winds NW quadrant: Radius of 48-knot winds NE quadrant: Radius of 48-knot winds SE quadrant: Radius of 48-knot winds SW quadrant: Radius of 48-knot winds NW quadrant: Radius of 64-knot winds: 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: 1004 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: 16/1800: 17.5S 113.8E: 055 (100): 030 (055): 998 +12: 17/0000: 17.5S 113.6E: 065 (120): 030 (055): 998 +18: 17/0600: 17.4S 113.5E: 070 (130): 030 (055): 998 +24: 17/1200: 17.4S 113.3E: 075 (140): 030 (055): 998 +36: 18/0000: 17.6S 113.3E: 090 (165): 030 (055): 997 +48: 18/1200: 17.8S 113.3E: 100 (190): 030 (055): 997 +60: 19/0000: 17.7S 113.1E: 115 (210): 030 (055): 998 +72: 19/1200: 17.6S 112.7E: 120 (220): 030 (055): 998 +96: 20/1200: 17.1S 110.6E: 145 (270): 035 (065): 994 +120: 21/1200: 17.0S 107.4E: 190 (350): 045 (085): 991 REMARKS: Tropical low 08U unlikely to develop significantly in the next few days. Intensity is 30 kn preserved from earlier ASCAT imagery (0210 UTC) that showed 30 kn to the north of the centre. The centre analysis is only fair extrapolating from earlier visible imagery. Renewed deep convection northeast of the centre is against the prevailing easterly wind shear but SSMIS 1028UTC microwave shows this being isolated from persisting convection west of the centre. Dvorak analysis: DT estimated at 1.5-2.0 but curvature is not clear on EIR. A steady 24h trend equates to a MET of 2.0 so FT/CI at 2.0, an increase from the 06UTC estimate. Recent objective guidance: ADT=3.3 (51kn), AiDT 41kn, DPRINT 32kn (1200 UTC, all 1-min average) (SATCON N/A). ADT remains higher than what scatterometry indicated. Convection continues to fluctuate, and the recent deep convection northeast of the centre could potentially indicate an easing of the prevailing wind shear. However, significantly more deep convection is required to moisten the circulation to enable sustained deep convection about the centre and development. While it is possible the environment improves on Sunday and Monday with lower shear, the most recent NWP now indicates a general delay for development until Wednesday. Somewhat surprisingly NWP suggests further intensification despite what appears to be a somewhat dry environment and only upper level outflow to the south. The official intensity forecast remains below most model guidance as a result. 08U has been moving slowly to the west as the ridge to the south is dominating the steering influences of the monsoonal flow to the north. The ridge will weaken in the next few days so slow and erratic motion will occur until later Tuesday. The ridge should build from Wednesday ensuring a westerly track is maintained in the following days. Copyright Commonwealth of Australia == The next bulletin for this system will be issued by: 16/1930 UTC.
Time (AWST) Intensity Category Latitude
(decimal deg.)Longitude
(decimal deg.)Estimated Position
Accuracy (km)0hr 8 pm March 16 tropical low 17.5S 113.9E 75 +6hr 2 am March 17 tropical low 17.5S 113.8E 100 +12hr 8 am March 17 tropical low 17.5S 113.6E 120 +18hr 2 pm March 17 tropical low 17.4S 113.5E 130 +24hr 8 pm March 17 tropical low 17.4S 113.3E 140 +36hr 8 am March 18 tropical low 17.6S 113.3E 165 +48hr 8 pm March 18 tropical low 17.8S 113.3E 190 +60hr 8 am March 19 tropical low 17.7S 113.1E 210 +72hr 8 pm March 19 tropical low 17.6S 112.7E 220 -