Tropical
Cyclones
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Tropical Cyclone SELWYN [Australian Region][South Indian Ocean][South Pacific Ocean][Southern Hemisphere][Summaries and Track Data] |
WTXS22 PGTW 971226 14:30z SUBJ/TROPICAL CYCLONE FORMATION ALERT 261423Z DEC 97// RMKS/ 1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN A 170 NM RADIUS OF 13.6S0 112.5E9 WITHIN THE NEXT 12 TO 24 HOURS. AVAILABLE DATA DOES NOT JUSTIFY ISSUANCE OF NUMBERED TROPICAL CYCLONE WARNINGS AT THIS TIME. WINDS IN THE AREA ARE ESTIMATED TO BE 15 TO 25 KNOTS. METSAT IMAGERY AT 261200Z INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 12.8S1 112.2E6. THE SYSTEM IS MOVING SOUTH-SOUTHEASTWARD AT 04 KNOTS. 2. REMARKS: A SCATTEROMETER PASS FROM 261529Z5 INDICATED THAT THE LOW LEVEL CIRCULATION CENTER IN THE SOUTHEAST INDIAN OCEAN HAD WINDS OF 15 TO 25 KNOTS. ALTHOUGH CONVECTION HAS BEEN LOCATED TO THE WEST OF THE LOW LEVEL CIRCULATION CENTER DURING MUCH OF THE DAY, RECENT SATELLITE DATA INDICATES THAT CONVECTION IS STARTING TO FORM CLOSER TOWARDS THE CENTER. SYNOPTIC CONDITIONS ARE FAVORABLE FOR DEVELOPMENT TO COMMENCE WITHIN THE NEXT 12 TO 24 HOURS. 3. THIS ALERT VALID UNTIL 271430Z7.// ========================================================================= WTXS32 PGTW 971227 03:00z THIS WARNING SUPERSEDES AND CANCELS NAVPACMETOCCEN WEST GU 261423Z DEC 97 TROPICAL CYCLONE FORMATION ALERT (WTXS22 PGTW 261430) 1. TROPICAL CYCLONE 09S WARNING NR 001 02 ACTIVE TROPICAL CYCLONES IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 270000Z9 --- 14.6S1 110.8E0 MOVEMENT PAST SIX HOURS - 225 DEGREES AT 08 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 REPEAT POSIT: 14.6S1 110.8E0 --- FORECASTS: 12 HRS, VALID AT: 271200Z2 --- 15.4S0 109.7E7 MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT RADIUS OF 035 KT WINDS - 040 NM SOUTHEAST SEMICIRCLE 035 NM ELSEWHERE VECTOR TO 24 HR POSIT: 250 DEG/ 07 KTS --- 24 HRS, VALID AT: 280000Z0 --- 15.9S5 108.4E3 MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT RADIUS OF 035 KT WINDS - 050 NM SOUTHEAST SEMICIRCLE 040 NM ELSEWHERE VECTOR TO 36 HR POSIT: 255 DEG/ 07 KTS --- 36 HRS, VALID AT: 281200Z3 --- 16.3S0 107.0E8 MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT RADIUS OF 035 KT WINDS - 055 NM SOUTHEAST SEMICIRCLE 040 NM ELSEWHERE VECTOR TO 48 HR POSIT: 250 DEG/ 07 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 290000Z1 --- 16.8S5 105.6E2 MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT RADIUS OF 050 KT WINDS - 020 NM RADIUS OF 035 KT WINDS - 060 NM SOUTHEAST SEMICIRCLE 045 NM ELSEWHERE --- REMARKS: 270300Z2 POSITION 14.8S3 110.5E7 TROPICAL CYCLONE 09S IS MOVING SOUTHWESTWARD AT 8 KNOTS. THE SYSTEM IS STILL CONSOLIDATING AND DIFFICULT TO POSITION. THE WARNING POSITION IS BASED ON 262330Z6 VISIBLE SATELLITE IMAGERY. INTENSIFICATION IS EXPECTED TO BE A SLOWER THAN CLIMATOLOGICAL RATE AS IT CONSOLIDATES. THE SUBTROPICAL RIDGE LOCATED TO THE SYSTEM=S SOUTH- SOUTHEAST IS EXPECTED TO CONTINUE TO PROVIDE THE DOMINANT STEERING INFLUENCE MOVING TC 09C SOUTHWESTWARD THROUGHOUT THE FORECAST PERIOD. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 270000Z IS 13 FEET. NEXT WARNINGS AT 271500Z5 (DTG 271353Z1) AND 280300Z3 (DTG 280153Z9). THIS WARNING SUPERSEDES AND CANCELS NAVPACMETOCCEN WEST GU 261423Z DEC 97 TROPICAL CYCLONE FORMATION ALERT (WTXS22 PGTW 261430) REFER TO TROPICAL CYCLONE 08S (SID) WARNINGS (WTPS31 PGTW) FOR TWELVE-HOURLY UPDATES.// ========================================================================= WTXS32 PGTW 971227 15:00z 1. TROPICAL CYCLONE 09S (SELWYN) WARNING NR 002 02 ACTIVE TROPICAL CYCLONES IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 271200Z2 --- 15.2S8 109.9E9 MOVEMENT PAST SIX HOURS - 230 DEGREES AT 06 KTS POSITION ACCURATE TO WITHIN 045 NM POSITION BASED ON EYE FIXED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT RADIUS OF 050 KT WINDS - 025 NM SOUTHEAST SEMICIRCLE 015 NM ELSEWHERE RADIUS OF 035 KT WINDS - 050 NM SOUTHEAST SEMICIRCLE 035 NM ELSEWHERE REPEAT POSIT: 15.2S8 109.9E9 --- FORECASTS: 12 HRS, VALID AT: 280000Z0 --- 15.7S3 108.8E7 MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT RADIUS OF 050 KT WINDS - 025 NM SOUTHEAST SEMICIRCLE 015 NM ELSEWHERE RADIUS OF 035 KT WINDS - 050 NM SOUTHEAST SEMICIRCLE 035 NM ELSEWHERE VECTOR TO 24 HR POSIT: 245 DEG/ 08 KTS --- 24 HRS, VALID AT: 281200Z3 --- 16.3S0 107.3E1 MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT RADIUS OF 050 KT WINDS - 025 NM SOUTHEAST SEMICIRCLE 015 NM ELSEWHERE RADIUS OF 035 KT WINDS - 055 NM SOUTHEAST SEMICIRCLE 040 NM ELSEWHERE VECTOR TO 36 HR POSIT: 245 DEG/ 08 KTS --- 36 HRS, VALID AT: 290000Z1 --- 17.0S8 105.8E4 MAX SUSTAINED WINDS - 080 KT, GUSTS 100 KT RADIUS OF 050 KT WINDS - 025 NM SOUTHEAST SEMICIRCLE 015 NM ELSEWHERE RADIUS OF 035 KT WINDS - 055 NM SOUTHEAST SEMICIRCLE 040 NM ELSEWHERE VECTOR TO 48 HR POSIT: 240 DEG/ 08 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 291200Z4 --- 17.9S7 104.3E8 MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT RADIUS OF 050 KT WINDS - 025 NM SOUTHEAST SEMICIRCLE 015 NM ELSEWHERE RADIUS OF 035 KT WINDS - 055 NM SOUTHEAST SEMICIRCLE 040 NM ELSEWHERE --- REMARKS: 271500Z5 POSITION 15.3S9 109.6E6 TROPICAL CYCLONE 09S (SELWYN) IS MOVING SOUTHWESTWARD AT 06 KNOTS. THE WARNING POSITION IS BASED ON 271036Z9 MICROWAVE IMAGERY (SSM/I). INFRARED IMAGERY SHOW A 7 NM CLOUD FILLED EYE. THE WARNING INTENSITY IS BASED ON A SATELLITE DERIVED INTENSITY ESTIMATE OF CI4.0 (65 KNOTS). THE SYSTEM IS FORECAST TO CONTINUE A SOUTHWESTWARD TRACK THROUGHOUT THE FORECAST PERIOD AS THE STEERING IS PROVIDED BY THE SUBTROPICAL RIDGE TO THE SOUTHEAST. TC 09S (SELWYN) IS EXPECTED TO INTENSITY VERY SLOWLY DUE TO SHEAR FROM THE NORTHWEST. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 271200Z IS 15 FEET. NEXT WARNINGS AT 280300Z3 (DTG 280153Z9) AND 281500Z6 (DTG 281353Z2). REFER TO TROPICAL CYCLONE 08S (SID) WARNINGS (WTPS31 PGTW) FOR TWELVE-HOURLY UPDATES.// ========================================================================= WTXS32 PGTW 971228 03:00z CORRECTED 1. TROPICAL CYCLONE 09S (SELWYN) WARNING NR 003A CORRECTED 02 ACTIVE TROPICAL CYCLONES IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 280000Z0 --- 15.5S1 109.0E0 MOVEMENT PAST SIX HOURS - 245 DEGREES AT 05 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT RADIUS OF 050 KT WINDS - 020 NM RADIUS OF 035 KT WINDS - 050 NM SOUTHEAST SEMICIRCLE 045 NM ELSEWHERE REPEAT POSIT: 15.5S1 109.0E0 --- FORECASTS: 12 HRS, VALID AT: 281200Z3 --- 16.0S7 108.1E0 MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT RADIUS OF 035 KT WINDS - 040 NM SOUTHEAST SEMICIRCLE 035 NM ELSEWHERE VECTOR TO 24 HR POSIT: 240 DEG/ 05 KTS --- 24 HRS, VALID AT: 290000Z1 --- 16.5S2 107.2E0 MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT RADIUS OF 035 KT WINDS - 040 NM SOUTHEAST SEMICIRCLE 035 NM ELSEWHERE VECTOR TO 36 HR POSIT: 240 DEG/ 06 KTS --- 36 HRS, VALID AT: 291200Z4 --- 17.1S9 106.2E9 MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 035 KT WINDS - 035 NM SOUTHEAST SEMICIRCLE 025 NM ELSEWHERE VECTOR TO 48 HR POSIT: 225 DEG/ 06 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 300000Z3 --- 17.9S7 105.3E9 MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 280300Z3 POSITION 15.6S2 108.8E7 TROPICAL CYCLONE 09S (SELWYN) IS MOVING WEST- SOUTHWESTWARD AT 5 KNOTS. WATER VAPOR IMAGERY INDICATES THAT THE SYSTEM IS EXPERIENCING SIGNIFICANT COLD DRY AIR ENTRAINMENT WHICH IS HINDERING CURRENT DEVELOPMENT. DEPARTING FROM THE INTENSITY FORECAST ISSUED IN OUR LAST WARNING, TC 09S (SELWYN) IS EXPECTED TO CONTINUE SLOWLY WEST-SOUTHWESTWARD AND WEAKEN DUE TO THE ENTRAINMENT AND UPPER-LEVEL VERTICAL WIND SHEAR. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 280000Z IS 15 FEET. NEXT WARNINGS AT 281500Z6 (DTG 281353Z2) AND 290300Z4 (DTG 290153Z0). REFER TO TROPICAL CYCLONE 08S (SID) WARNINGS (WTPS31 PGTW) FOR TWELVE-HOURLY UPDATES. JUSTIFICATION FOR COR: CORRECTED SYSTEM=S DIRECTION OF MOVEMENT// ========================================================================= WTXS32 PGTW 971228 15:00z 1. TROPICAL CYCLONE 09S (SELWYN) WARNING NR 004 02 ACTIVE TROPICAL CYCLONES IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 281200Z3 --- 16.3S0 107.9E7 MOVEMENT PAST SIX HOURS - 240 DEGREES AT 06 KTS POSITION ACCURATE TO WITHIN 045 NM POSITION BASED ON EYE FIXED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT RADIUS OF 050 KT WINDS - 020 NM RADIUS OF 035 KT WINDS - 050 NM SOUTHEAST SEMICIRCLE 045 NM ELSEWHERE REPEAT POSIT: 16.3S0 107.9E7 --- FORECASTS: 12 HRS, VALID AT: 290000Z1 --- 16.8S5 106.8E5 MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT RADIUS OF 035 KT WINDS - 040 NM SOUTHEAST SEMICIRCLE 035 NM ELSEWHERE VECTOR TO 24 HR POSIT: 240 DEG/ 07 KTS --- 24 HRS, VALID AT: 291200Z4 --- 17.5S3 105.6E2 MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT RADIUS OF 035 KT WINDS - 040 NM SOUTHEAST SEMICIRCLE 035 NM ELSEWHERE VECTOR TO 36 HR POSIT: 240 DEG/ 07 KTS --- 36 HRS, VALID AT: 300000Z3 --- 18.2S1 104.3E8 MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 035 KT WINDS - 035 NM SOUTHEAST SEMICIRCLE 025 NM ELSEWHERE VECTOR TO 48 HR POSIT: 240 DEG/ 07 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 301200Z6 --- 18.9S8 103.1E5 MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 281500Z6 POSITION 16.4S1 107.6E4 TROPICAL CYCLONE 09S (SELWYN) IS MOVING WEST- SOUTHWESTWARD AT 06 KNOTS. THE WARNING POSITION AND INTENSITY ARE BASED ON 281130Z5 INFRARED SATELLITE IMAGERY. THE SYSTEM IS EXPECTED TO WEAKEN AS IT ENCOUNTERS CONTINUE UPPER-LEVEL WINDS SHEAR. TC 09S (SELWYN) IS FORECAST TO CONTINUE A WEST-SOUTHWESTWARD TRACK THROUGHOUT THE FORECAST PERIOD. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 281200Z IS 15 FEET. NEXT WARNINGS AT 290300Z4 (DTG 290153Z0) AND 291500Z7 (DTG 291353Z3). REFER TO TROPICAL CYCLONE 08S (SID) WARNING 06 (WTPS31 PGTW) FOR FINAL WARNING.// ========================================================================= WTXS32 PGTW 971229 03:00z 1. TROPICAL CYCLONE 09S (SELWYN) WARNING NR 005 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 290000Z1 --- 17.6S4 107.0E8 MOVEMENT PAST SIX HOURS - 215 DEGREES AT 08 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT RADIUS OF 050 KT WINDS - 025 NM RADIUS OF 035 KT WINDS - 050 NM SOUTHEAST SEMICIRCLE 045 NM ELSEWHERE REPEAT POSIT: 17.6S4 107.0E8 --- FORECASTS: 12 HRS, VALID AT: 291200Z4 --- 18.8S7 106.3E0 MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT RADIUS OF 050 KT WINDS - 020 NM RADIUS OF 035 KT WINDS - 045 NM SOUTHEAST SEMICIRCLE 040 NM ELSEWHERE VECTOR TO 24 HR POSIT: 220 DEG/ 07 KTS --- 24 HRS, VALID AT: 300000Z3 --- 19.9S9 105.4E0 MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT RADIUS OF 035 KT WINDS - 040 NM SOUTHEAST SEMICIRCLE 035 NM ELSEWHERE VECTOR TO 36 HR POSIT: 255 DEG/ 07 KTS --- 36 HRS, VALID AT: 301200Z6 --- 20.3S5 104.0E5 MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT RADIUS OF 035 KT WINDS - 035 NM SOUTH SEMICIRCLE 025 NM ELSEWHERE VECTOR TO 48 HR POSIT: 265 DEG/ 07 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 310000Z4 --- 20.4S6 102.5E8 MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 290300Z4 POSITION 17.9S7 106.8E5 TROPICAL CYCLONE 09S (SELWYN) IS MOVING SOUTHWEST AT 8 KNOTS. THE SYSTEM IS CONTINUING TO SHOW SOME SIGNS OF COLD AIR ENTRAINMENT AND UPPER LEVEL VERTICAL WIND SHEAR, BUT HAS MAINTAINED A HIGH INTENSITY OVER THE PAST 24 HOURS. THE SYSTEM IS FORECAST TO MOVE INTO AN ENVIRONMENT OF INCREASED VERTICAL WIND SHEAR WITHIN THE NEXT 12 TO 36 HOURS, CAUSING IT TO WEAKEN CONSIDERABLY. AS TC 09S (SELWYN) SHEARS, THE LOW-LEVEL CIRCULATION IS EXPECTED TO TRACK WESTWARD. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 290000Z IS 15 FEET. NEXT WARNINGS AT 291500Z7 (DTG 291353Z3) AND 300300Z6 (DTG 300153Z2).// ========================================================================= WTXS32 PGTW 971229 15:00z 1. TROPICAL CYCLONE 09S (SELWYN) WARNING NR 006 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 291200Z4 --- 18.1S0 104.1E6 MOVEMENT PAST SIX HOURS - 250 DEGREES AT 13 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT RADIUS OF 035 KT WINDS - 050 NM SOUTHEAST SEMICIRCLE 045 NM ELSEWHERE REPEAT POSIT: 18.1S0 104.1E6 --- FORECASTS: 12 HRS, VALID AT: 300000Z3 --- 18.9S8 102.1E4 MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT RADIUS OF 035 KT WINDS - 045 NM SOUTHEAST SEMICIRCLE 040 NM ELSEWHERE VECTOR TO 24 HR POSIT: 255 DEG/ 10 KTS --- 24 HRS, VALID AT: 301200Z6 --- 19.4S4 100.1E2 MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT RADIUS OF 035 KT WINDS - 040 NM SOUTHEAST SEMICIRCLE 035 NM ELSEWHERE VECTOR TO 36 HR POSIT: 255 DEG/ 10 KTS --- 36 HRS, VALID AT: 310000Z4 --- 19.8S8 98.3E0 MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT RADIUS OF 035 KT WINDS - 035 NM SOUTH SEMICIRCLE 025 NM ELSEWHERE VECTOR TO 48 HR POSIT: 260 DEG/ 10 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 311200Z7 --- 20.2S4 96.1E6 MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 291500Z7 POSITION 18.3S2 103.6E0 TROPICAL CYCLONE 09S (SELWYN) IS MOVING WEST- SOUTHWESTWARD AT 13 KNOTS. THE SYSTEM IS EXPECTED TO SLOW AND TAKE ON A SLIGHTLY MORE WESTWARD MOTION DURING THE FORECAST PERIOD. WE BELIEVE THAT THE DOMINANT STEERING FLOW ON 09S (SELWYN) WILL BE THE EASTERLIES EQUATORWARD OF THE LOWER TROPOSPHERIC (850 MB) SUBTROPICAL RIDGE. THE WARNING POSITION AND INTENSITY ARE BASED ON 291130Z6 INFRARED SATELLITE IMAGERY. TC 09S (SELWYN) IS FORECAST TO WEAKEN DUE TO MODERATE TO HEAVY UPPER LEVEL WIND SHEAR FROM THE NORTHWEST. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 291200Z4 IS 15 FEET. NEXT WARNINGS AT 300300Z6 (DTG 300153Z2) AND 301500Z9 (DTG 301353Z5).// ========================================================================= WTXS32 PGTW 971230 03:00z 1. TROPICAL CYCLONE 09S (SELWYN) WARNING NR 007 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 300000Z3 --- 17.1S9 103.0E4 MOVEMENT PAST SIX HOURS - 290 DEGREES AT 09 KTS POSITION ACCURATE TO WITHIN 045 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT RADIUS OF 035 KT WINDS - 050 NM NORTHEAST SEMICIRCLE 040 NM ELSEWHERE REPEAT POSIT: 17.1S9 103.0E4 --- FORECASTS: 12 HRS, VALID AT: 301200Z6 --- 16.4S1 101.3E5 MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER VECTOR TO 24 HR POSIT: 300 DEG/ 09 KTS --- 24 HRS, VALID AT: 310000Z4 --- 15.5S1 99.8E6 MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 300300Z6 POSITION 16.9S6 102.6E9 TROPICAL CYCLONE 09S (SELWYN) IS MOVING WEST- NORTHWESTWARD AT 09 KNOTS. THE WARNING POSITION IS BASED UPON 292330Z9 VISIBLE SATELLITE IMAGERY. CURRENTLY, THE SYSTEM IS WEAKENING DUE TO VERTICAL WIND SHEAR WITH THE NEAREST DEEP CONVECTION LOCATED APPROXIMATELY 100NM SOUTHEAST OF THE CENTER. THE WARNING INTENSITY IS BASED UPON A SATELLITE INTENSITY ESTIMATE OF 45 KNOTS. TROPICAL CYCLONE 09S (SELWYN) SHOULD WEAKEN THROUGHOUT THE FORECAST PERIOD AS VERTICAL WIND SHEAR IS EXPECTED TO CONTINUE ACROSS THE CENTER. THE FORECAST TRACK HAS BEEN SHIFTED SLIGHTLY NORTH OF THE PREVIOUS WARNING TO REFLECT THE MORE RECENT WEST-NORTHWESTWARD MOTION OF THE SYSTEM. THE SYSTEM SHOULD MOVE WEST-NORTHWESTWARD FOR THE ENTIRE FORECAST PERIOD DUE TO THE LOW LEVEL EAST-SOUTHEASTERLY FLOW FROM HIGH PRESSURE LOCATED SOUTH OF THE CENTER. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 300000Z IS 13 FEET. NEXT WARNING AT 301500Z9 (DTG 301353Z5).// ========================================================================= WTXS32 PGTW 971230 15:00z 1. TROPICAL CYCLONE 09S (SELWYN) WARNING NR 008 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 301200Z6 --- 16.4S1 101.1E3 MOVEMENT PAST SIX HOURS - 295 DEGREES AT 10 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT RADIUS OF 035 KT WINDS - 050 NM NORTHEAST SEMICIRCLE 040 NM ELSEWHERE REPEAT POSIT: 16.4S1 101.1E3 --- FORECASTS: 12 HRS, VALID AT: 310000Z4 --- 15.6S2 99.2E0 MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER VECTOR TO 24 HR POSIT: 285 DEG/ 09 KTS --- 24 HRS, VALID AT: 311200Z7 --- 15.1S7 97.4E0 MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 301500Z9 POSITION 16.2S9 100.6E7 TROPICAL CYCLONE 09S (SELWYN) CONTINUES TO MOVE TOWARDS THE WEST-NORTHWEST AND HAS INCREASED ITS FORWARD SPEED SLIGHTLY TO 10 KNOTS. THE WARNING POSITION AND INTENSITY ARE BASED ON 301130Z8 INFRARED SATELLITE IMAGERY. ANIMATED INFRARED IMAGERY SHOWS THE CONVECTION ASSOCIATED WITH TC 09S HAS INCREASED SLIGHTLY OVER THE PAST 6 HOURS. HOWEVER, THE LOW-LEVEL CIRCULATION REMAINS APPROXIMATELY 40NM AWAY FROM THE CLOSEST DEEP CONVECTION. THE FORECAST TRACK REMAINS SIMILAR AS TROPICAL CYCLONE 09S (SELWYN) IS EXPECTED TO TRACK TOWARDS THE WEST-NORTHWEST UNDER THE INFLUENCE OF THE SUBTROPICAL RIDGE. THE SYSTEM IS FORECAST TO WEAKEN SLOWLY THROUGHOUT THE FORECAST PERIOD AS AN INCREASE IN WIND SHEAR IS EXPECTED. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 301200Z6 IS 13 FEET. REFER TO WWIO31 PGFW FOR ADDITIONAL SEA HEIGHT INFORMATION. NEXT WARNINGS AT 310300Z7 (DTG 310153Z3).// ========================================================================= WTXS32 PGTW 971231 03:00z 1. TROPICAL CYCLONE 09S (SELWYN) WARNING NR 009 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 310000Z4 --- 16.4S1 100.0E1 MOVEMENT PAST SIX HOURS - 280 DEGREES AT 07 KTS POSITION ACCURATE TO WITHIN 045 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT REPEAT POSIT: 16.4S1 100.0E1 --- FORECASTS: 12 HRS, VALID AT: 311200Z7 --- 16.2S9 98.6E3 MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER VECTOR TO 24 HR POSIT: 280 DEG/ 07 KTS --- 24 HRS, VALID AT: 010000Z1 --- 15.9S5 97.1E7 MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 310300Z7 POSITION 16.4S1 99.6E4 TROPICAL CYCLONE 09S (SELWYN) HAS MOVED WESTWARD AT 07 KNOTS FOR THE PAST 06 HOURS. THE WARNING POSITION IS BASED ON 202330Z0 VISIBLE SATELLITE IMAGERY ANALYZED BY PHIK ANALYSTS AND CONTINUITY FROM A 301611Z2 SCATTEROMETER PASS WHICH ALSO INDICATED THAT THE MAXIMUM INTENSITY WAS 35 KNOTS. THE CONVECTION WITH THIS SYSTEM HAS DIMINISHED WITH THE NEAREST CONVECTIVE CELLS LOCATED APPROXIMATELY 65NM FROM THE SYSTEM CENTER. TROPICAL CYCLONE 09S (SELWYN) SHOULD CONTINUE WESTWARD FOR THE NEXT 24 HOURS AS IT IS STEERED PRIMARILY BY LOW LEVEL FLOW FROM HIGH PRESSURE LOCATED SOUTH OF THE CENTER. THE SYSTEM SHOULD CONTINUE TO WEAKEN SLOWLY THROUGHOUT THE PERIOD AS AN UPPER LEVEL TROUGH APPROACHES FROM THE WEST INCREASING THE VERTICAL WIND SHEAR. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 310000Z IS 13 FEET. NEXT WARNINGS AT 311500Z0 (DTG 311353Z6).// ========================================================================= WTXS32 PGTW 971231 15:00z 1. TROPICAL CYCLONE 09S (SELWYN) WARNING NR 010 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 311200Z7 --- 16.3S0 98.4E1 MOVEMENT PAST SIX HOURS - 270 DEGREES AT 08 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 REPEAT POSIT: 16.3S0 98.4E1 --- FORECASTS: 12 HRS, VALID AT: 010000Z1 --- 16.2S9 96.8E3 MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER VECTOR TO 24 HR POSIT: 270 DEG/ 08 KTS --- 24 HRS, VALID AT: 011200Z4 --- 16.2S9 95.2E6 MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 311500Z0 POSITION 16.3S0 98.0E7 TROPICAL CYCLONE 09S (SELWYN) IS MOVING TOWARDS THE WEST AT 8 KNOTS. THE WARNING POSITION AND INTENSITY ARE BASED ON 311130Z9 INFRARED SATELLITE IMAGERY. OVER THE PAST 12 HOURS, ANIMATION SHOWS TC 09S IS EXPERIENCING SIGNIFICANT WIND SHEAR FROM MOSTLY THE NORTH AND CONVECTION REMAINS MINIMAL. HOWEVER, DURING THE PAST 3 HOURS CONVECTION HAS BECOME MORE CENTRALLY LOCATED TOWARDS THE EXPOSED LOW- LEVEL CIRCULATION AND IS NOW LOCATED APPROXIMATELY 40NM FROM THE CENTER. TROPICAL CYCLONE 09S (SELWYN) IS EXPECTED TO TRACK TOWARDS THE WEST THROUGH THE FORECAST PERIOD AS IT IS STEERED BY LOW-LEVEL EASTERLY FLOW. THE SYSTEM IS EXPECTED TO WEAKEN SLOWLY AS AN APPROACHING UPPER-LEVEL TROUGH IS EXPECTED TO PASS THROUGH THE AREA AND INTRODUCE ADDITIONAL VERTICAL WIND SHEAR ON TC 09S. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 311200Z7 IS 13 FEET. REFER TO WWIO31 PGFW FOR ADDITIONAL SEA HEIGHT INFORMATION. NEXT WARNINGS AT 010300Z4 (DTG 010153Z0).// ========================================================================= WTXS32 PGTW 980101 03:00z CORRECTED 1. TROPICAL CYCLONE 09S (SELWYN) WARNING NR 011 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 010000Z1 --- 16.3S0 96.2E7 MOVEMENT PAST SIX HOURS - 270 DEGREES AT 10 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER REPEAT POSIT: 16.3S0 96.2E7 --- FORECASTS: 12 HRS, VALID AT: 011200Z4 --- 16.7S4 94.2E5 MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 010300Z4 POSITION 16.4S1 95.7E1 TROPICAL CYCLONE 09S (SELWYN) HAS DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE. THE WARNING INTENSITY IS BASED ON VISIBLE SATELLITE IMAGERY. THE SYSTEM HAS ONLY SLIGHT PERIPHERAL CONVECTION AND IS SUBJECT TO HEAVY NORTHERLY SHEAR. TC 09S (SELWYN) IS EXPECTED TO REMAIN IN A HIGH WINDSHEAR ENVIRONMENT. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 98010000Z IS 12 FEET. THIS IS THE FINAL WARNING ON THIS SYSTEM BY THE JOINT TYPHOON WARNING CENTER (NAVPACMETOCCEN WEST GU). THE SYSTEM WILL BE CLOSELY MONITORED FOR SIGNS OF REGENERATION.//
Document: selwyn.htm
Updated: 26th December 2006 |
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