最新回复 (87)
-
AXAU01 APRF 140106 IDW27600 TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE at: 0105 UTC 14/03/2024 Name: Tropical Low Identifier: 08U Data At: 0000 UTC Latitude: 15.4S Longitude: 113.5E Location Accuracy: within 25nm (45 km) Movement Towards: east (094 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: 994 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: 120 nm (220 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: 150 nm (280 km) FORECAST DATA Date/Time : Location : Loc. Accuracy: Max Wind : Central Pressure (UTC) : degrees : nm (km): knots(km/h): hPa +06: 14/0600: 15.8S 114.3E: 040 (080): 035 (065): 996 +12: 14/1200: 16.1S 115.2E: 060 (110): 035 (065): 996 +18: 14/1800: 16.4S 115.9E: 075 (135): 035 (065): 995 +24: 15/0000: 16.7S 116.2E: 090 (165): 035 (065): 995 +36: 15/1200: 17.3S 116.3E: 105 (195): 035 (065): 994 +48: 16/0000: 17.6S 115.7E: 130 (240): 035 (065): 995 +60: 16/1200: 17.9S 115.1E: 145 (270): 045 (085): 989 +72: 17/0000: 18.0S 114.5E: 165 (305): 050 (095): 986 +96: 18/0000: 18.7S 113.3E: 210 (390): 060 (110): 977 +120: 19/0000: 20.2S 112.3E: 295 (545): 055 (100): 981 REMARKS: Tropical Low 08U continues under the influence of strong deep layer easterly wind shear. The low level circulation continues to be exposed and at times there are multiple centres. Convection has been displaced to the west of the LLCC, waxing and waning with the diurnal cycle; with some development during the last 6 hrs. Confidence in the centre position is fair based on animated Vis imagery and slightly earlier SSMIS microwave imagery at 2023 UTC. Dvorak analysis: Shear pattern gives DT 2.0 with the estimated centre displaced 0.75 degrees from the deep convection. MET is 2.0 based on a 24 hour D- trend, and PT agrees. FT of 2.0 based on MET/PAT, with CI also 2.0. Objective guidance: ADT 33kt, AiDT 32kt, DPRINT 32kt, and SATCON 40kt (all 1-min average). Earlier (Wednesday morning) scatterometry indicated a broad swathe of max 30 knot winds in the monsoon dominated flow to the north, but these winds are expected to fluctuate around 30 to 35 knots diurnally so intensity has been maintained at 35 knots with gales in the northern quadrants only. 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. From Friday, the influence of a mid-level ridge to the south will begin to slow the system down. At the same time, 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 Saturday. 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. 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. There is, however, a large spread in the guidance due to different relative strengths of modelled steering influences, with some favouring a track further east before turning, and/or more southerly movement. An approach close to or across the western Pilbara coast early next week therefore remains possible. Copyright Commonwealth of Australia == The next bulletin for this system will be issued by: 14/0730 UTC.
Time (AWST) Intensity Category Latitude
(decimal deg.)Longitude
(decimal deg.)Estimated Position
Accuracy (km)0hr 8 am March 14 tropical low 15.4S 113.5E 45 +6hr 2 pm March 14 tropical low 15.8S 114.3E 80 +12hr 8 pm March 14 tropical low 16.1S 115.2E 110 +18hr 2 am March 15 tropical low 16.4S 115.9E 135 +24hr 8 am March 15 tropical low 16.7S 116.2E 165 +36hr 8 pm March 15 tropical low 17.3S 116.3E 195 +48hr 8 am March 16 tropical low 17.6S 115.7E 240 +60hr 8 pm March 16 1 17.9S 115.1E 270 +72hr 8 am March 17 2 18.0S 114.5E 305 -
WTXS32 PGTW 140300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 012// RMKS/ 1. TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 012 01 ACTIVE TROPICAL CYCLONES IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 140000Z --- NEAR 15.6S 113.9E MOVEMENT PAST SIX HOURS - 100 DEGREES AT 12 KTS POSITION ACCURATE TO WITHIN 020 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 - 000 NM NORTHEAST QUADRANT 000 NM SOUTHEAST QUADRANT 045 NM SOUTHWEST QUADRANT 035 NM NORTHWEST QUADRANT REPEAT POSIT: 15.6S 113.9E --- FORECASTS: 12 HRS, VALID AT: 141200Z --- 16.1S 115.4E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 000 NM NORTHEAST QUADRANT 025 NM SOUTHEAST QUADRANT 045 NM SOUTHWEST QUADRANT 035 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 125 DEG/ 05 KTS --- 24 HRS, VALID AT: 150000Z --- 16.7S 116.3E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 000 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 045 NM SOUTHWEST QUADRANT 035 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 170 DEG/ 03 KTS --- 36 HRS, VALID AT: 151200Z --- 17.2S 116.4E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 000 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 045 NM SOUTHWEST QUADRANT 040 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 215 DEG/ 02 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 160000Z --- 17.6S 116.1E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 000 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 045 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 240 DEG/ 03 KTS --- 72 HRS, VALID AT: 170000Z --- 18.2S 114.9E MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 000 NM NORTHEAST QUADRANT 015 NM SOUTHEAST QUADRANT 015 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 020 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 225 DEG/ 02 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 180000Z --- 18.9S 114.2E MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 000 NM NORTHEAST QUADRANT 010 NM SOUTHEAST QUADRANT 010 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 000 NM NORTHEAST QUADRANT 015 NM SOUTHEAST QUADRANT 015 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 020 NM NORTHEAST QUADRANT 060 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT VECTOR TO 120 HR POSIT: 210 DEG/ 04 KTS --- 120 HRS, VALID AT: 190000Z --- 20.2S 113.4E MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 000 NM NORTHEAST QUADRANT 015 NM SOUTHEAST QUADRANT 015 NM SOUTHWEST QUADRANT 000 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 020 NM NORTHEAST QUADRANT 085 NM SOUTHEAST QUADRANT 060 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT --- REMARKS: 140300Z POSITION NEAR 15.7S 114.3E. 14MAR24. TROPICAL CYCLONE 18S (EIGHTEEN), LOCATED APPROXIMATELY 402 NM NORTH OF LEARMONTH, AUSTRALIA, HAS TRACKED EASTWARD AT 12 KNOTS OVER THE PAST SIX HOURS. MINIMUM CENTRAL PRESSURE AT 140000Z IS 998 MB. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 140000Z IS 13 FEET. NEXT WARNINGS AT 140900, 141500Z, 142100Z AND 150300Z.// NNNN
WDXS32 PGTW 140300 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 012// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 15.6S 113.9E INITIAL INTENSITY: 35 KTS GEOGRAPHIC REFERENCE: 402 NM NORTH OF LEARMONTH, AUSTRALIA MOVEMENT PAST 6 HOURS: EASTWARD AT 12 KTS SIGNIFICANT WAVE HEIGHT: 13 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS THE FLARING CENTRAL CONVECTION SHEARED WESTWARD OF A FULLY EXPOSED LOW LEVEL CIRCULATION CENTER (LLCC). THERE IS MINIMAL POLEWARD OUTFLOW AND NO ORGANIZED FEEDER BANDS. ANALYSIS INDICATES A MARGINAL ENVIRONMENT WITH VERY WARM SST AND WEAK POLEWARD OUTFLOW ALOFT GREATLY OFFSET BY STRONG (30-40 KTS) VERTICAL WIND SHEAR (VWS). THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE BASED ON THE EXPOSED LLCC IN THE MSI LOOP. THE INITIAL INTENSITY IS PLACED WITH MEDIUM CONFIDENCE BASED ON OVERALL ASSESSMENT OF AGENCY AND OBJECTIVE DVORAK INTENSITY ESTIMATES. INITIAL WIND RADII BASIS: MOST RECENT 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: T2.0 - 30 KTS CIMSS ADT: 34 KTS AT 132330Z CIMSS AIDT: 33 KTS AT 132330Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL VWS: 30-40 KTS SST: 30-31 CELSIUS OUTFLOW: WEAK POLEWARD ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: HIGH 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 CONTINUE EAST-SOUTHEASTWARD UNDER THE NER. AFTER TAU 24, A SUBTROPICAL RIDGE TO THE EAST, ANCHORED OVER AUSTRALIA, WILL ASSUME STEERING AND DRIVE THE SYSTEM SOUTHWARD THEN SOUTHWESTWARD. AS THE STORM MOTION BECOMES MORE IN-PHASE WITH THE UPPER-LEVEL WIND FLOW, VWS IS EXPECTED TO WEAKEN, AND POLEWARD OUTFLOW TO IMPROVE, A STEADY INTENSIFICATION IS EXPECTED, PEAKING AT 70KTS BY TAU 96. AFTERWARD, COOLING SST AND INCREASING VWS WILL BEGIN TO ERODE THE SYSTEM, AND BY TAU 120, WILL BE REDUCED TO 60 KTS AS IT COMES TO WITHIN 120NM TO THE NORTH OF LEARMONTH. MODEL DISCUSSION: NUMERICAL MODELS ARE IN BETTER AGREEMENT SPREADING OUT TO 1103NM AT TAU 72 AND 287NM AT TAU 120, LENDING MEDIUM CONFIDENCE TO THE NEAR- TO MID-PORTION OF THE JTWC TRACK FORECAST. AFTERWARD, THE SPREAD BECOMES MORE UNEVEN AND WIDER TO 241NM BY TAU 120, 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
-
AXAU01 APRF 140705 IDW27600 TROPICAL CYCLONE TECHNICAL BULLETIN: AUSTRALIA - WESTERN REGION Issued by AUSTRALIAN BUREAU OF METEOROLOGY TROPICAL CYCLONE WARNING CENTRE at: 0659 UTC 14/03/2024 Name: Tropical Low Identifier: 08U Data At: 0600 UTC Latitude: 15.9S Longitude: 114.7E Location Accuracy: within 25nm (45 km) Movement Towards: east southeast (111 deg) Speed of Movement: 8 knots (15 km/h) Maximum 10-Minute Wind: 35 knots (65 km/h) Maximum 3-Second Wind Gust: 50 knots (95 km/h) Central Pressure: 996 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: 120 nm (220 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/D0.5/24HRS STT:W0.5/06HRS Pressure of outermost isobar: 1003 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: 14/1200: 16.2S 115.4E: 045 (080): 035 (065): 996 +12: 14/1800: 16.5S 115.9E: 060 (110): 035 (065): 995 +18: 15/0000: 16.8S 116.1E: 075 (135): 035 (065): 995 +24: 15/0600: 17.0S 116.2E: 080 (150): 035 (065): 995 +36: 15/1800: 17.5S 116.3E: 095 (180): 035 (065): 995 +48: 16/0600: 17.8S 115.8E: 115 (215): 035 (065): 992 +60: 16/1800: 18.0S 115.1E: 135 (250): 040 (075): 989 +72: 17/0600: 18.2S 114.6E: 160 (295): 045 (085): 982 +96: 18/0600: 19.2S 113.4E: 210 (390): 060 (110): 977 +120: 19/0600: 20.9S 112.3E: 275 (510): 045 (085): 984 REMARKS: Tropical Low 08U continues under the influence of strong deep layer easterly wind shear. The low level circulation is exposed and at times there are multiple centres. Convection has been displaced to the west of the LLCC, waxing and waning with the diurnal cycle; with some weakening during the last 6 hrs as the centre has moved further east from the deepest convection. Confidence in the centre position is fair based on animated Vis imagery, though our analysis is weighted just to the west of the visible centre due to our multiple centres. Dvorak analysis: Shear pattern gives DT 1.5 with the estimated centre displaced 1.25 degrees from the deep convection. MET is 1.5 based on a 24 hour D- trend, and PT agrees. FT of 1.5 based on MET/PAT, with CI held above at 2.0. Objective guidance: ADT 34kn, AiDT 35kn, DPRINT 27kn, DMIT 30kn and SATCON 45kn (all 1-min average). ASCAT at 0110 UTC this morning had gales in northern quadrants and supportes continuing with an intensity (10-min mean) of 35kn. 08U is currently tracking east-southeast 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. From Friday, the influence of a mid-level ridge to the south will begin to slow the system down. At the same time, 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. 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. There is, however, a large spread in the guidance due to different relative strengths of modelled steering influences, with some favouring a track further east before turning, and/or more southerly movement. An approach close to or across the western Pilbara coast early next week therefore remains possible. Copyright Commonwealth of Australia == The next bulletin for this system will be issued by: 14/1330 UTC.
Time (AWST) Intensity Category Latitude
(decimal deg.)Longitude
(decimal deg.)Estimated Position
Accuracy (km)0hr 2 pm March 14 tropical low 15.9S 114.7E 45 +6hr 8 pm March 14 tropical low 16.2S 115.4E 80 +12hr 2 am March 15 tropical low 16.5S 115.9E 110 +18hr 8 am March 15 tropical low 16.8S 116.1E 135 +24hr 2 pm March 15 tropical low 17.0S 116.2E 150 +36hr 2 am March 16 tropical low 17.5S 116.3E 180 +48hr 2 pm March 16 tropical low 17.8S 115.8E 215 +60hr 2 am March 17 1 18.0S 115.1E 250 +72hr 2 pm March 17 1 18.2S 114.6E 295 -
WTXS32 PGTW 140900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 013// RMKS/ 1. TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 013 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 140600Z --- NEAR 16.2S 115.0E MOVEMENT PAST SIX HOURS - 115 DEGREES AT 13 KTS POSITION ACCURATE TO WITHIN 030 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 - 000 NM NORTHEAST QUADRANT 000 NM SOUTHEAST QUADRANT 045 NM SOUTHWEST QUADRANT 035 NM NORTHWEST QUADRANT REPEAT POSIT: 16.2S 115.0E --- FORECASTS: 12 HRS, VALID AT: 141800Z --- 16.9S 115.8E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT 010 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 110 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 150 DEG/ 03 KTS --- 24 HRS, VALID AT: 150600Z --- 17.4S 116.1E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 070 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 040 NM SOUTHWEST QUADRANT 080 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 205 DEG/ 02 KTS --- 36 HRS, VALID AT: 151800Z --- 17.8S 115.9E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT 040 NM SOUTHEAST QUADRANT 050 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 230 DEG/ 02 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 160600Z --- 18.1S 115.5E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 060 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT VECTOR TO 72 HR POSIT: 240 DEG/ 03 KTS --- 72 HRS, VALID AT: 170600Z --- 18.7S 114.5E MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 080 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 080 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT VECTOR TO 96 HR POSIT: 215 DEG/ 03 KTS --- LONG RANGE OUTLOOK: --- 96 HRS, VALID AT: 180600Z --- 19.8S 113.7E MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 015 NM NORTHEAST QUADRANT 015 NM SOUTHEAST QUADRANT 015 NM SOUTHWEST QUADRANT 015 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 070 NM SOUTHEAST QUADRANT 070 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT VECTOR TO 120 HR POSIT: 205 DEG/ 03 KTS --- 120 HRS, VALID AT: 190600Z --- 20.7S 113.2E MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 064 KT WINDS - 015 NM NORTHEAST QUADRANT 015 NM SOUTHEAST QUADRANT 015 NM SOUTHWEST QUADRANT 015 NM NORTHWEST QUADRANT RADIUS OF 050 KT WINDS - 030 NM NORTHEAST QUADRANT 030 NM SOUTHEAST QUADRANT 030 NM SOUTHWEST QUADRANT 030 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 050 NM NORTHEAST QUADRANT 080 NM SOUTHEAST QUADRANT 080 NM SOUTHWEST QUADRANT 060 NM NORTHWEST QUADRANT --- REMARKS: 140900Z POSITION NEAR 16.4S 115.2E. 14MAR24. TROPICAL CYCLONE 18S (EIGHTEEN), LOCATED APPROXIMATELY 370 NM NORTH OF LEARMONTH, AUSTRALIA, HAS TRACKED EAST- SOUTHEASTWARD AT 13 KNOTS OVER THE PAST SIX HOURS. MINIMUM CENTRAL PRESSURE AT 140600Z IS 998 MB. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 140600Z IS 14 FEET. NEXT WARNINGS AT 141500Z, 142100Z, 150300Z AND 150900Z.// NNNN
WDXS32 PGTW 140900 MSGID/GENADMIN/JOINT TYPHOON WRNCEN PEARL HARBOR HI// SUBJ/PROGNOSTIC REASONING FOR TROPICAL CYCLONE 18S (EIGHTEEN) WARNING NR 013// RMKS/ 1. FOR METEOROLOGISTS. 2. 6 HOUR SUMMARY AND ANALYSIS. SUMMARY: INITIAL POSITION: 16.2S 115.0E INITIAL INTENSITY: 35 KTS GEOGRAPHIC REFERENCE: 370 NM NORTH OF LEARMONTH, AUSTRALIA MOVEMENT PAST 6 HOURS: EAST-SOUTHEASTWARD AT 13 KTS SIGNIFICANT WAVE HEIGHT: 14 FEET SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: TROPICAL CYCLONE (TC) 18S CONTINUES TO STRUGGLE UNDER HIGH VERTICAL WIND SHEAR AND REMAINS WELL-DEFINED AND FULLY-EXPOSED AS REVEALED IN THE ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI). THEREFORE, THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE. A 140202Z ASCAT-C IMAGE SHOWS AN ASYMMETRIC WIND FIELD WITH A SWATH OF 35 KNOT WINDS TO THE NORTH, WHICH SUPPORTS THE INITIAL INTENSITY ASSESSMENT OF 35 KNOTS WITH HIGH CONFIDENCE. AGENCY SUBJECTIVE DVORAK ESTIMATES REMAIN SLIGHTLY LOWER AT 30 KNOTS, WITH UW-CIMSS ADT AND AIDT ESTIMATES RANGING BETWEEN 34 TO 35 KNOTS. INITIAL WIND RADII BASIS: PERSISTENCE 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 APRF: T2.0 - 30 KTS CIMSS SATCON: 43 KTS AT 140159Z CIMSS ADT: 34 KTS AT 140600Z CIMSS AIDT: 35 KTS AT 140600Z FORECASTER ASSESSMENT OF CURRENT ENVIRONMENT: MARGINAL VWS: 25-30 KTS SST: 30-31 CELSIUS OUTFLOW: MODERATE WESTWARD ANALYSIS CONFIDENCE: INITIAL POSITION: HIGH INITIAL INTENSITY: HIGH 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 WILL SLOW AND GRADUALLY TURN SOUTHWARD TO SOUTHWESTWARD THROUGH TAU 72 AS THE AFOREMENTIONED 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 DECREASE ALLOWING THE SYSTEM TO CONSOLIDATE. AFTER TAU 72, TC 18S WILL ACCELERATE SLIGHTLY AS IT TRACKS SOUTH-SOUTHWESTWARD TOWARD A BREAK IN THE STR ASSOCIATED WITH AN APPROACHING SHORTWAVE TROUGH AND FRONTAL SYSTEM. AFTER TAU 96, A STRONG LOW-LEVEL HIGH IS EXPECTED TO BUILD TO THE SOUTH OVER WESTERN AUSTRALIA EFFECTIVELY BLOCKING AND SLOWING POLEWARD PROGRESSION. AFTER TAU 72, ENVIRONMENTAL CONDITIONS APPEAR CONDUCIVE, WITH LOW VWS AND IMPROVING POLEWARD OUTFLOW INTO THE MIDLATITUDE SHORTWAVE TROUGH, WHICH WILL LEAD TO MODERATE INTENSIFICATION TO A PEAK INTENSITY OF 70 KNOTS BY TAU 96. MODEL DISCUSSION: WITH THE EXCEPTION OF NAVGEM, DETERMINISTIC NUMERICAL MODEL GUIDANCE REMAINS IN FAIR AGREEMENT WITH A 165 NM CROSS-TRACK SPREAD AT TAU 72 AND 245 NM AT TAU 120. THE 140000Z ECMWF ENSEMBLE (EPS) AND GFS ENSEMBLE (GEFS) ALSO INDICATE INCREASING UNCERTAINTY AFTER TAU 72, WITH A VERY LARGE SPREAD IN SOLUTIONS. THE 140000Z COAMPS-TC INTENSITY ENSEMBLE (CTCXEPS) SHOWS INCREASING INTENSITY PROBABILITIES OF MODERATE INTENSIFICATION, WITH PEAK PROBABILITY VALUES RANGING FROM 60 TO 90 PERCENT FROM TAU 54 TO TAU 100. RAPID INTENSIFICATION PROBABILITIES REMAIN LOW AT LESS THAN 30 PERCENT AFTER TAU 48. FORECAST CONFIDENCE: TRACK 0 - 72 HR: MEDIUM TRACK 72-120 HR: LOW INTENSITY 0 - 72 HR: MEDIUM INTENSITY 72-120 HR: LOW// NNNN
-
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： -
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
-
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