Tropical
Cyclones
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Tropical Cyclone ALISON [Australian Region][South Indian Ocean][South Pacific Ocean][Southern Hemisphere][Summaries and Track Data] |
WTXS31 PGTW 981108 15:00z 1. TROPICAL CYCLONE 04S (ALISON) WARNING NR 001 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 081200Z1 --- 11.8S0 98.2E9 MOVEMENT PAST SIX HOURS - 240 DEGREES AT 06 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: 11.8S0 98.2E9 --- FORECASTS: 12 HRS, VALID AT: 090000Z9 --- 12.2S5 97.4E0 MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT RADIUS OF 035 KT WINDS - 050 NM SOUTHEAST SEMICIRCLE 045 NM ELSEWHERE VECTOR TO 24 HR POSIT: 235 DEG/ 05 KTS --- 24 HRS, VALID AT: 091200Z2 --- 12.7S0 96.6E1 MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT RADIUS OF 050 KT WINDS - 020 NM SOUTHEAST SEMICIRCLE 015 NM ELSEWHERE RADIUS OF 035 KT WINDS - 070 NM SOUTHEAST SEMICIRCLE 065 NM ELSEWHERE VECTOR TO 36 HR POSIT: 240 DEG/ 06 KTS --- 36 HRS, VALID AT: 100000Z1 --- 13.3S7 95.6E0 MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT RADIUS OF 050 KT WINDS - 040 NM SOUTHEAST SEMICIRCLE 035 NM ELSEWHERE RADIUS OF 035 KT WINDS - 090 NM SOUTHEAST SEMICIRCLE 080 NM ELSEWHERE VECTOR TO 48 HR POSIT: 240 DEG/ 06 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 101200Z4 --- 13.9S3 94.6E9 MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT RADIUS OF 050 KT WINDS - 055 NM SOUTHEAST SEMICIRCLE 045 NM ELSEWHERE RADIUS OF 035 KT WINDS - 110 NM SOUTHEAST SEMICIRCLE 100 NM ELSEWHERE --- REMARKS: 081500Z4 POSITION 11.9S1 98.0E7. TROPICAL CYCLONE 04S (ALISON) HAS FORMED IN THE SOUTHERN INDIAN OCEAN AND IS MOVING WEST-SOUTHWESTWARD AT 6 KNOTS. THE WARNING POSITION IS BASED ON 081130Z3 INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON 081130Z3 SATELLITE INTENSITY ESTIMATES OF 35 KNOTS. TROPICAL CYCLONE 04S (ALISON) IS TRACKING WEST-SOUTHWESTWARD UNDER THE STEERING FLOW FROM THE SUBTROPICAL RIDGE TO ITS SOUTH. THIS STEERING SHOULD CONTINUE THROUGHOUT THE FORECAST PERIOD. TROPICAL CYCLONE 04S (ALISON) IS FORECAST TO INTENSIFY CLIMATOLOGICALLY AT ONE DVORAK T-NUMBER PER DAY AS IT WILL REMAIN IN AN ENVIRONMENT FAVORABLE FOR INTENSIFICATION. WIND RADII ARE BASED ON CLIMATOLOGY FOR AN AVERAGE-SIZED TROPICAL CYCLONE. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 081200Z1 IS 12 FEET. NEXT WARNINGS AT 090300Z2 (DTG 090151Z6) AND 091500Z5 (DTG 091351Z9). THIS WARNING SUPERSEDES AND CANCELS NAVPACMETOCCEN WEST GU 080948Z NOVEMBER 98 TROPICAL CYCLONE FORMATION ALERT (WTXS21 PGTW 080600).// ========================================================================= WTXS31 PGTW 981108 21:00z SUBJ: TROPICAL CYCLONE WARNING 1. TROPICAL CYCLONE 04S (ALISON) WARNING NR 002 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 081800Z7 --- 13.1S5 97.3E9 MOVEMENT PAST SIX HOURS - 225 DEGREES AT 11 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT RADIUS OF 050 KT WINDS - 020 NM SOUTHEAST SEMICIRCLE 015 NM ELSEWHERE RADIUS OF 035 KT WINDS - 070 NM SOUTHEAST SEMICIRCLE 065 NM ELSEWHERE REPEAT POSIT: 13.1S5 97.3E9 --- FORECASTS: 12 HRS, VALID AT: 090600Z5 --- 14.2S7 96.0E5 MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT RADIUS OF 050 KT WINDS - 040 NM SOUTHEAST SEMICIRCLE 030 NM ELSEWHERE RADIUS OF 035 KT WINDS - 090 NM SOUTHEAST SEMICIRCLE 080 NM ELSEWHERE VECTOR TO 24 HR POSIT: 225 DEG/ 08 KTS --- 24 HRS, VALID AT: 091800Z8 --- 15.3S9 94.8E1 MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT RADIUS OF 050 KT WINDS - 055 NM SOUTHEAST SEMICIRCLE 045 NM ELSEWHERE RADIUS OF 035 KT WINDS - 110 NM SOUTHEAST SEMICIRCLE 100 NM ELSEWHERE VECTOR TO 36 HR POSIT: 225 DEG/ 08 KTS --- 36 HRS, VALID AT: 100600Z7 --- 16.4S1 93.6E8 MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT RADIUS OF 050 KT WINDS - 070 NM SOUTHEAST SEMICIRCLE 060 NM ELSEWHERE RADIUS OF 035 KT WINDS - 135 NM SOUTHEAST SEMICIRCLE 125 NM ELSEWHERE VECTOR TO 48 HR POSIT: 225 DEG/ 08 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 101800Z0 --- 17.5S3 92.4E5 MAX SUSTAINED WINDS - 100 KT, GUSTS 125 KT RADIUS OF 050 KT WINDS - 080 NM SOUTHEAST SEMICIRCLE 070 NM ELSEWHERE RADIUS OF 035 KT WINDS - 145 NM SOUTHEAST SEMICIRCLE 135 NM ELSEWHERE --- REMARKS: 082100Z1 POSITION 13.4S8 97.0E6. TROPICAL CYCLONE 04S (ALISON) HAS TRACKED SOUTHWESTWARD AT 11 KNOTS OVER THE PAST 6 HOURS. THE WARNING POSITION IS BASED ON 081730Z9 INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON A 081730Z9 SATELLITE INTENSITY ESTIMATE OF 55 KNOTS FROM PGTW. TROPICAL CYCLONE 04S (ALISON) HAS RAPIDLY INTENSIFIED OVER THE PAST 6 HOURS. 081730Z9 INFRARED IMAGERY SHOWS CONTINUED CLOUD TOP COOLING AND IMPROVED ORGANIZATION WITH A SUGGESTION OF THE DEVELOPMENT OF A WARM SPOT INDICATIVE OF A 55 KNOT SYSTEM. 081800Z7 OBSERVATION FROM COCOS ISLAND (WMO 96996) SHOW SUSTAINED 34 KNOTS (TEN-MINUTE AVERAGE) WINDS WITH GUSTS TO 47 KNOTS (TEN- MINUTE AVERAGE). TROPICAL CYCLONE 04S (ALISON) HAS BEEN MOVING SOUTHWESTWARD UNDER THE STEERING FLOW FROM THE SUBTROPICAL RIDGE TO ITS SOUTH. THIS SHOULD REMAIN THE DOMINANT STEERING THROUGHOUT THE FORECAST PERIOD. HOWEVER, AN APPROACHING MID-LATITUDE TROUGH MAY WEAKEN THE SUBTROPICAL RIDGE SUFFICIENTLY TO IMPART A MORE SOUTHWARD COMPONENT TO THE TRACK AFTER THE 36-HOUR FORECAST POSITION. TROPICAL CYCLONE 04S (ALISON) IS FORECAST TO CONTINUE TO INTENSIFY THROUGHOUT THE FORECAST PERIOD AS IT SHOULD REMAIN IN AN ENVIRONMENT FAVORABLE FOR CONTINUED INTENSIFICATION. WIND RADII HAVE BEEN ADJUSTED BASED ON SURFACE SYNOPTIC DATA. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 081800Z IS 16 FEET. NEXT WARNINGS AT 090300Z2 (DTG 090151Z6) AND 091500Z5 (DTG 091351Z9).// ========================================================================= WTXS31 PGTW 981109 03:00z SUBJ: TROPICAL CYCLONE WARNING 1. TROPICAL CYCLONE 04S (ALISON) WARNING NR 003 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 090000Z9 --- 13.5S9 96.8E3 MOVEMENT PAST SIX HOURS - 230 DEGREES AT 06 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 055 KT, GUSTS 070 KT RADIUS OF 050 KT WINDS - 025 NM SOUTHEAST SEMICIRCLE 020 NM ELSEWHERE RADIUS OF 035 KT WINDS - 100 NM SOUTHEAST SEMICIRCLE OVER WATER 090 NM ELSEWHERE OVER WATER REPEAT POSIT: 13.5S9 96.8E3 --- FORECASTS: 12 HRS, VALID AT: 091200Z2 --- 14.1S6 95.4E8 MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT RADIUS OF 050 KT WINDS - 040 NM SOUTHEAST SEMICIRCLE 030 NM ELSEWHERE RADIUS OF 035 KT WINDS - 105 NM SOUTHEAST SEMICIRCLE 095 NM ELSEWHERE VECTOR TO 24 HR POSIT: 245 DEG/ 08 KTS --- 24 HRS, VALID AT: 100000Z1 --- 14.7S2 93.9E1 MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT RADIUS OF 050 KT WINDS - 055 NM SOUTHEAST SEMICIRCLE 045 NM ELSEWHERE RADIUS OF 035 KT WINDS - 110 NM SOUTHEAST SEMICIRCLE 100 NM ELSEWHERE VECTOR TO 36 HR POSIT: 245 DEG/ 07 KTS --- 36 HRS, VALID AT: 101200Z4 --- 15.3S9 92.6E7 MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT RADIUS OF 050 KT WINDS - 070 NM SOUTHEAST SEMICIRCLE 060 NM ELSEWHERE RADIUS OF 035 KT WINDS - 135 NM SOUTHEAST SEMICIRCLE 125 NM ELSEWHERE VECTOR TO 48 HR POSIT: 250 DEG/ 07 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 110000Z2 --- 15.8S4 91.2E2 MAX SUSTAINED WINDS - 100 KT, GUSTS 125 KT RADIUS OF 050 KT WINDS - 080 NM SOUTHEAST SEMICIRCLE 070 NM ELSEWHERE RADIUS OF 035 KT WINDS - 145 NM SOUTHEAST SEMICIRCLE 135 NM ELSEWHERE --- REMARKS: 090300Z2 POSITION 13.7S1 96.4E9. TROPICAL CYCLONE (TC) 04S (ALISON) HAS TRACKED SOUTHWESTWARD JUST SOUTH OF COCOS ISLAND AT 6 KNOTS OVER THE PAST 6 HOURS. THE WARNING POSITION IS BASED UPON ANIMATED INFRARED SATELLITE IMAGERY AND A 082330Z6 VISIBLE SATELLITE IMAGE. THE WARNING INTENSITY IS BASED UPON SATELLITE INTENSITY ESTIMATES OF 55 KNOTS. TROPICAL CYCLONE 04S (ALISON) IS TRACKING SOUTHWESTWARD UNDER THE STEERING INFLUENCE OF THE SUBTROPICAL RIDGE TO ITS SOUTH. ALTHOUGH THE FORECAST PHILOSOPHY REMAINS BASICALLY THE SAME FOR TC 04S (ALISON), THE FORECAST TRACK WAS SHIFTED SLIGHTLY WESTWARD AND SLOWED DUE TO THE SHIFTING INFLUENCE OF THE AFOREMENTIONED SUBTROPICAL RIDGE. TROPICAL CYCLONE 04S (ALISON) SHOULD CONTINUE TO INTENSIFY THROUGHOUT THE FORECAST PERIOD AS THE UPPER LEVEL ENVIRONMENT REMAINS FAVORABLE FOR FUTHER DEVELOPMENT. THE WIND RADII ARE BASED UPON CLIMATOLOGY FOR AN AVERAGE-SIZED TROPICAL CYCLONE AND HAVE BEEN ADJUSTED IN ACCORDANCE WITH SURFACE SYNOPTIC DATA FROM COCOS ISLAND. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 090000Z9 IS 14 FEET. NEXT WARNINGS AT 091500Z5 (DTG 091351Z9) AND 100300Z4 (DTG 100151Z8).// ========================================================================= WTXS31 PGTW 981109 15:00z 1. TROPICAL CYCLONE 04S (ALISON) WARNING NR 004 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 091200Z2 --- 13.8S2 095.6E0 MOVEMENT PAST SIX HOURS - 250 DEGREES AT 09 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT RADIUS OF 050 KT WINDS - 045 NM SOUTHEAST SEMICIRCLE 035 NM ELSEWHERE RADIUS OF 035 KT WINDS - 100 NM SOUTHEAST SEMICIRCLE 090 NM ELSEWHERE REPEAT POSIT: 13.8S2 095.6E0 --- FORECASTS: 12 HRS, VALID AT: 100000Z1 --- 14.2S7 094.3E6 MAX SUSTAINED WINDS - 080 KT, GUSTS 100 KT RADIUS OF 050 KT WINDS - 050 NM SOUTHEAST SEMICIRCLE 040 NM ELSEWHERE RADIUS OF 035 KT WINDS - 105 NM SOUTHEAST SEMICIRCLE 095 NM ELSEWHERE VECTOR TO 24 HR POSIT: 250 DEG/ 07 KTS --- 24 HRS, VALID AT: 101200Z4 --- 14.6S1 093.0E2 MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT RADIUS OF 050 KT WINDS - 055 NM SOUTHEAST SEMICIRCLE 045 NM ELSEWHERE RADIUS OF 035 KT WINDS - 110 NM SOUTHEAST SEMICIRCLE 100 NM ELSEWHERE VECTOR TO 36 HR POSIT: 250 DEG/ 07 KTS --- 36 HRS, VALID AT: 110000Z2 --- 15.1S7 091.7E7 MAX SUSTAINED WINDS - 095 KT, GUSTS 115 KT RADIUS OF 050 KT WINDS - 060 NM SOUTHEAST SEMICIRCLE 050 NM ELSEWHERE RADIUS OF 035 KT WINDS - 120 NM SOUTHEAST SEMICIRCLE 110 NM ELSEWHERE VECTOR TO 48 HR POSIT: 245 DEG/ 06 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 111200Z5 --- 15.6S2 090.5E4 MAX SUSTAINED WINDS - 100 KT, GUSTS 125 KT RADIUS OF 050 KT WINDS - 070 NM SOUTHEAST SEMICIRCLE 060 NM ELSEWHERE RADIUS OF 035 KT WINDS - 130 NM SOUTHEAST SEMICIRCLE 120 NM ELSEWHERE --- REMARKS: 091500Z5 POSITION 13.9S3 095.3E7. TROPICAL CYCLONE 04S (ALISON) HAS TRACKED WEST-SOUTHWESTWARD AT 9 KNOTS OVER THE PAST 6 HOURS. THE WARNING POSITION IS BASED ON 091142Z7 INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY OF 70 KNOTS IS BASED ON 091130Z4 SATELLITE INTENSITY ESTIMATES OF 65 AND 75 KNOTS. TROPICAL CYCLONE 04S (ALISON) CONTINUES TO INTENSIFY AND IS MOVING WEST-SOUTHWESTWARD UNDER THE STEERING INFLUENCE OF THE SUBTROPICAL RIDGE TO ITS SOUTHWEST. ANIMATED WATER VAPOR IMAGERY SHOWS THIS RIDGE IS REBUILDING AND HAS DEVELOPED A NORTHWEST- SOUTHEAST ORIENTATION. THE STEERING FLOW FROM THIS RIDGE SHOULD KEEP TROPICAL CYCLONE 04S (ALISON) MOVING WEST-SOUTHWESTWARD THROUGHOUT THE FORECAST PERIOD. TROPICAL CYCLONE 04S (ALISON) IS FORECAST TO CONTINUE TO INTENSIFY THROUGHOUT THE FORECAST PERIOD. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 091200Z2 IS 16 FEET. NEXT WARNINGS AT 100300Z4 (DTG 100151Z8) AND 101500Z7 (DTG 101351Z1).// ========================================================================= WTXS31 PGTW 981110 03:00z 1. TROPICAL CYCLONE 04S (ALISON) WARNING NR 005 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 100000Z1 --- NEAR 14.7S2 93.8E0 MOVEMENT PAST SIX HOURS - 235 DEGREES AT 08 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT RADIUS OF 050 KT WINDS - 045 NM SOUTHEAST SEMICIRCLE 035 NM ELSEWHERE RADIUS OF 035 KT WINDS - 100 NM SOUTHEAST SEMICIRCLE 090 NM ELSEWHERE REPEAT POSIT: 14.7S2 93.8E0 --- FORECASTS: 12 HRS, VALID AT: 101200Z4 --- 15.3S9 92.5E6 MAX SUSTAINED WINDS - 070 KT, GUSTS 085 KT RADIUS OF 050 KT WINDS - 050 NM SOUTHEAST SEMICIRCLE 040 NM ELSEWHERE RADIUS OF 035 KT WINDS - 105 NM SOUTHEAST SEMICIRCLE 095 NM ELSEWHERE VECTOR TO 24 HR POSIT: 250 DEG/ 07 KTS --- 24 HRS, VALID AT: 110000Z2 --- 15.7S3 91.2E2 MAX SUSTAINED WINDS - 080 KT, GUSTS 100 KT RADIUS OF 050 KT WINDS - 055 NM SOUTHEAST SEMICIRCLE 045 NM ELSEWHERE RADIUS OF 035 KT WINDS - 110 NM SOUTHEAST SEMICIRCLE 100 NM ELSEWHERE VECTOR TO 36 HR POSIT: 255 DEG/ 07 KTS --- 36 HRS, VALID AT: 111200Z5 --- 16.0S7 89.8E5 MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT RADIUS OF 050 KT WINDS - 060 NM SOUTHEAST SEMICIRCLE 050 NM ELSEWHERE RADIUS OF 035 KT WINDS - 120 NM SOUTHEAST SEMICIRCLE 110 NM ELSEWHERE VECTOR TO 48 HR POSIT: 250 DEG/ 07 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 120000Z3 --- 16.4S1 88.5E1 MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT RADIUS OF 050 KT WINDS - 070 NM SOUTHEAST SEMICIRCLE 060 NM ELSEWHERE RADIUS OF 035 KT WINDS - 130 NM SOUTHEAST SEMICIRCLE 120 NM ELSEWHERE --- REMARKS: 100300Z4 POSITION NEAR 14.9S4 93.5E7. ANIMATED INFRARED SATELLITE IMAGERY SHOWS TROPICAL CYCLONE 04S (ALISON) HAS CONTINUED TRACKING TOWARDS THE SOUTHWEST AT 8 KNOTS. THE WARNING POSITION IS BASED ON 092330Z7 INFRARED SATELLITE IMAGERY AND ANIMATION. THE WARNING INTENSITY IS BASED ON A COMBINATION OF SATELLITE DERIVED INTENSITY ESTIMATES BETWEEN 65 AND 77 KNOTS. THE FORECAST PHILOSOPHY REMAINS SIMILAR AS TC 04S IS EXPECTED TO CONTINUE GENERALLY TOWARDS THE SOUTHWEST UNDER THE INFLUENCE OF THE SUBTROPICAL RIDGE. THROUGH THE 12 HOUR PERIOD, TC 04S IS EXPECTED TO MAINTAIN ITS CURRENT INTENSITY AS IT IS INFLUENCED BY A PASSING MID-LATITUDE TROUGH. AFTERWARDS, TC 04S IS EXPECTED TO INTENSIFY SLOWLY THROUGH THE REMAINDER OF THE FORECAST PERIOD. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 100000Z IS 16 FEET. NEXT WARNINGS AT 101500Z7 (DTG 101351Z1) AND 110300Z5 (DTG 110151Z9).// ========================================================================= WTXS31 PGTW 981110 15:00z 1. TROPICAL CYCLONE 04S (ALISON) WARNING NR 006 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 101200Z4 --- NEAR 16.3S0 92.8E9 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 - 070 KT, GUSTS 085 KT RADIUS OF 050 KT WINDS - 045 NM SOUTHEAST SEMICIRCLE 035 NM ELSEWHERE RADIUS OF 035 KT WINDS - 100 NM SOUTHEAST SEMICIRCLE 090 NM ELSEWHERE REPEAT POSIT: 16.3S0 92.8E9 --- FORECASTS: 12 HRS, VALID AT: 110000Z2 --- 17.6S4 91.9E9 MAX SUSTAINED WINDS - 075 KT, GUSTS 090 KT RADIUS OF 050 KT WINDS - 050 NM SOUTHEAST SEMICIRCLE 040 NM ELSEWHERE RADIUS OF 035 KT WINDS - 105 NM SOUTHEAST SEMICIRCLE 095 NM ELSEWHERE VECTOR TO 24 HR POSIT: 205 DEG/ 08 KTS --- 24 HRS, VALID AT: 111200Z5 --- 19.0S0 91.2E2 MAX SUSTAINED WINDS - 080 KT, GUSTS 100 KT RADIUS OF 050 KT WINDS - 055 NM SOUTHEAST SEMICIRCLE 045 NM ELSEWHERE RADIUS OF 035 KT WINDS - 110 NM SOUTHEAST SEMICIRCLE 100 NM ELSEWHERE VECTOR TO 36 HR POSIT: 185 DEG/ 08 KTS --- 36 HRS, VALID AT: 120000Z3 --- 20.5S7 91.0E0 MAX SUSTAINED WINDS - 085 KT, GUSTS 105 KT RADIUS OF 050 KT WINDS - 060 NM SOUTHEAST SEMICIRCLE 050 NM ELSEWHERE RADIUS OF 035 KT WINDS - 120 NM SOUTHEAST SEMICIRCLE 110 NM ELSEWHERE VECTOR TO 48 HR POSIT: 175 DEG/ 09 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 121200Z6 --- 22.3S7 91.2E2 MAX SUSTAINED WINDS - 090 KT, GUSTS 110 KT RADIUS OF 050 KT WINDS - 070 NM SOUTHEAST SEMICIRCLE 060 NM ELSEWHERE RADIUS OF 035 KT WINDS - 130 NM SOUTHEAST SEMICIRCLE 120 NM ELSEWHERE --- REMARKS: 101500Z7 POSITION NEAR 16.6S3 92.6E7. TROPICAL CYCLONE 04S (ALISON) HAS TRACKED TOWARDS THE SOUTHWEST AT 8 KNOTS FOR THE PAST 12 HOURS. THE WARNING POSITION AND INTENSITY ARE BASED ON 101130Z6 INFRARED SATELLITE IMAGERY AND ANIMATION. THE TRACK WAS CONFIRMED BY 100343Z1 SCATTEROMETRY DATA. TC 04S IS EXPECTED TO CONTINUE TOWARDS THE SOUTHWEST UNDER THE INFLUENCE OF THE SUBTROPICAL RIDGE. THROUGH THE 12-HOUR PERIOD, TC 04S IS EXPECTED TO MAINTAIN ITS CURRENT INTENSITY AS IT IS INFLUENCED BY A PASSING MID-LATITUDE TROUGH. BY THE 36-HOUR POINT, THE PASSING TROUGH IS EXPECTED TO CAUSE A SOUTHWARD TURN IN THE FORECAST TRACK. TC 04S IS EXPECTED TO INTENSIFY SLOWLY THROUGH THE REMAINDER OF THE FORECAST PERIOD. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 101200Z4 IS 16 FEET. REFER TO WWIO31 PGFW FOR ADDITIONAL SEA HEIGHT INFORMATION. NEXT WARNINGS AT 110300Z5 (DTG 110151Z9) AND 111500Z8 (DTG 111351Z2). ========================================================================= WTXS31 PGTW 981111 03:00z 1. TROPICAL CYCLONE 04S (ALISON) WARNING NR 007 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 110000Z2 --- NEAR 17.5S3 92.4E5 MOVEMENT PAST SIX HOURS - 180 DEGREES AT 06 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT RADIUS OF 050 KT WINDS - 020 NM RADIUS OF 035 KT WINDS - 075 NM EAST SEMICIRCLE 065 NM ELSEWHERE REPEAT POSIT: 17.5S3 92.4E5 --- FORECASTS: 12 HRS, VALID AT: 111200Z5 --- 18.5S4 92.3E4 MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT RADIUS OF 050 KT WINDS - 015 NM RADIUS OF 035 KT WINDS - 075 NM EAST SEMICIRCLE 065 NM ELSEWHERE VECTOR TO 24 HR POSIT: 180 DEG/ 04 KTS --- 24 HRS, VALID AT: 120000Z3 --- 19.4S4 92.3E4 MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT RADIUS OF 035 KT WINDS - 065 NM SOUTHEAST SEMICIRCLE 055 NM ELSEWHERE VECTOR TO 36 HR POSIT: 180 DEG/ 04 KTS --- 36 HRS, VALID AT: 121200Z6 --- 20.1S3 92.3E4 MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 035 KT WINDS - 060 NM EAST SEMICIRCLE 050 NM ELSEWHERE VECTOR TO 48 HR POSIT: 180 DEG/ 03 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 130000Z4 --- 20.8S0 92.4E5 MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 110300Z5 POSITION NEAR 17.8S6 92.4E5. ANIMATED INFRARED SATELLITE IMAGERY SHOWS TROPICAL CYCLONE 04S (ALISON) HAS TRACKED TOWARDS THE SOUTH OVER THE LAST 12 HOURS. THE WARNING POSITION IS BASED ON 102330Z9 INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON A COMBINATION OF SATELLITE DERIVED INTENSITY ESTIMATES. THE CURRENT WIND RADII HAVE BEEN ADJUSTED SLIGHTLY BASED ON 100343Z1 SCATTEROMETRY DATA. TC 04S IS FORECAST TO CONTINUE TRACKING GENERALLY TOWARDS THE SOUTH THROUGHOUT THE FORECAST PERIOD. ADDITIONALLY, THE SYSTEM IS EXPECTED TO WEAKEN DUE TO COLDER SEA SURFACE TEMPERATURES AND INCREASED WIND SHEAR. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 110000Z2 IS 15 FEET. NEXT WARNINGS AT 111500Z8 (DTG 111351Z2) AND 120300Z6 (DTG 120151Z0).// ========================================================================= WTXS31 PGTW 981111 14:00z 1. TROPICAL CYCLONE 04S (ALISON) WARNING NR 008 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WARNING POSITION: 111200Z5 --- NEAR 18.3S2 91.7E7 MOVEMENT PAST SIX HOURS - 205 DEGREES AT 07 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MALSUSTAINED WINDS - 065 KT, GUSTS 080 KT RADIUS OF 050 KT WINDS - 020 NM RADIUS OF 035 KT WINDS - 075 NM EAST SEMICIRCLE 065 NM ELSDWHERE REPEAT POSIT: 18.3S2 91.7E7 FORECASTS: 12 HRS, VALID AT: 120000Z3 --- 19.5S5 91.0E0 MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT RADIUS OF 050 KT WINDS - 015 NM RADIUS OF 035 KT WINDS - 075 NM EAST SEMICIRCLE 8 065 NM ELSEWHERE VECTOR TO 24 HR POSIT: 205 DEG/ 06 KTS 24 HRS, VALID AT: 121200Z6 --- 20.5S7 90.5E4 MAX SUSTAINED WINDS 2 050 KT, GUSTS 065 KT RADIUS OF 035 KT WINDS - 065 NM SOUTHEAST SEMICIRCLE 055 NM ELSEWHERE VECTOR TO 36 HR POSIT: 180 DEG/ 06 KTS 36 HRS, VALID AT: 130000Z4 --- 21.8S1 90.4E3 MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT RADIUS OF 035 KT WINDS - 060 NM EAST SEMICIRCLE 050 NM ELSEWHERE VECTOR TO 48 HR POSIT: 170 DEG/ 07 KTS EXTENDED OUTLOOK: 48 HRS, VALID AT: 131200Z7 --- 23.2S7 90.7E6 MAX SUTAINED WINDS - 035 KT, GUSTS 045 KT REMARKS: 111500Z8 POSITION NEAR 18.6S5 91.5E5. ANIMATED INFRARED SATELLITE IMAGERY SHOWS TROPICAL CYCLONE 04S (ALISON) HAS TRACKED TOWARDS THE SOUTH-SOUTHWEST OVER THE PAST 12 HOURS. THE WARNING POSITION AND INTENSITY ARE BASED ON 111130Z7 INFRARED SATELLITE IMAGERY. TC 04S IS FORECAST TO CONTINUE TRACKING TOWARDS THE SOUTH THROUGHOUT THE FORECAST PERIOD. ADDITIONALLY, THE SYSTEM IS EXPECTED TO WEAKEN DUE TO COLDER SEA SURFACE TEMPERATURES AND INCREASED VERTICAL WIND SHEAR. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 111200Z5 IS 15 FEET. REFER TO WWIO31 PGFW FOR ADDITIONAL SEA HEIGHT INFORMATION. NEXT WARNINGS AT 120300Z6 (DTG 120151Z0) AND 121500Z9 (DTG 121351Z3).// ========================================================================= WTXS31 PGTW 981112 03:00z 1. TROPICAL CYCLONE 04S (ALISON) WARNING NR 009 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 120000Z3 --- NEAR 19.5S5 92.0E1 MOVEMENT PAST SIX HOURS - 160 DEGREES AT 05 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT RADIUS OF 050 KT WINDS - 020 NM RADIUS OF 035 KT WINDS - 075 NM EAST SEMICIRCLE 065 NM ELSEWHERE REPEAT POSIT: 19.5S5 92.0E1 --- FORECASTS: 12 HRS, VALID AT: 121200Z6 --- 20.4S6 92.2E3 MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT RADIUS OF 050 KT WINDS - 015 NM RADIUS OF 035 KT WINDS - 075 NM EAST SEMICIRCLE 065 NM ELSEWHERE VECTOR TO 24 HR POSIT: 170 DEG/ 06 KTS --- 24 HRS, VALID AT: 130000Z4 --- 21.5S8 92.4E5 MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT RADIUS OF 035 KT WINDS - 065 NM SOUTHEAST SEMICIRCLE 055 NM ELSEWHERE VECTOR TO 36 HR POSIT: 155 DEG/ 04 KTS --- 36 HRS, VALID AT: 131200Z7 --- 22.3S7 92.8E9 MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER VECTOR TO 48 HR POSIT: 145 DEG/ 04 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 140000Z5 --- 22.9S3 93.3E5 MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 120300Z6 POSITION NEAR 19.7S7 92.0E1. TROPICAL CYCLONE 04S (ALISON) HAS TRACKED SOUTH-SOUTHEASTWARD AT 5 KNOTS OVER THE PAST 6 HOURS. THE WARNING POSITION AND INTENSITY ARE BASED UPON ANIMATED INFRARED SATELLITE IMAGERY. TC 04S (ALISON) IS FORECAST TO CONTINUE IN A SOUTH-SOUTHEASTWARD TRACK FOR THE REMAINDER OF THE FORECAST PERIOD. HOWEVER, ANIMATED WATER VAPOR IMAGERY INDICATED TC 04S (ALISON) IS UNDERGOING MODERATE TO SEVERE SHEAR. HENCE, TS 04S (ALISON) SHOULD DISSIPATE OVER WATER BY THE 48 HOUR PERIOD. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 120000Z3 IS 15 FEET. NEXT WARNINGS AT 121500Z9 (DTG 121351Z3) AND 130300Z7 (DTG 130151Z1).// ========================================================================= WTXS31 PGTW 981112 15:00z 1. TROPICAL CYCLONE 04S (ALISON) WARNING NR 010 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 121200Z6 --- NEAR 18.9S8 090.8E7 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 - 055 KT, GUSTS 070 KT RADIUS OF 050 KT WINDS - 015 NM RADIUS OF 035 KT WINDS - 065 NM REPEAT POSIT: 18.9S8 090.8E7 --- FORECASTS: 12 HRS, VALID AT: 130000Z4 --- 18.7S6 090.2E1 MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT RADIUS OF 035 KT WINDS - 055 NM VECTOR TO 24 HR POSIT: 290 DEG/ 03 KTS --- 24 HRS, VALID AT: 131200Z7 --- 18.5S4 089.6E3 MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT RADIUS OF 035 KT WINDS - 045 NM VECTOR TO 36 HR POSIT: 285 DEG/ 04 KTS --- 36 HRS, VALID AT: 140000Z5 --- 18.3S2 088.8E4 MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER VECTOR TO 48 HR POSIT: 275 DEG/ 04 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 141200Z8 --- 18.2S1 088.0E6 MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 121500Z9 POSITION NEAR 18.9S8 090.6E5. TROPICAL CYCLONE 04S (ALISON) HAS TRACKED WEST-NORTHWESTWARD AT 3 KNOTS OVER THE PAST 6 HOURS. THE WARNING POSITION IS BASED UPON 121130Z8 INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON 121130Z8 SATELLITE INTENSITY ESTIMATES OF 45 KNOTS AND 121030Z7 VISIBLE SATELLITE IMAGERY SHOWING A TIGHTLY WRAPPED LOW-LEVEL CIRCULATION INDICATIVE OF A MORE INTENSE SYSTEM. TROPICAL CYCLONE 04S (ALISON) IS AN EXPOSED LOW-LEVEL CIRCULATION WITH ITS DEEP CONVECTION SHEARED TO THE SOUTHEAST. THE FORECAST TRACK CONTINUES THE SYSTEM TOWADS THE WEST-NORTHWEST BECOMING MORE WESTWARD WITHIN THE LOW-LEVEL STEERING FLOW. TROPICAL CYCLONE 04S (ALISON) SHOULD DISSIPATE OVER WATER BY THE END OF THE 48 HOUR FORECAST PERIOD. MAXIMUM SIGNIFICANT WAVE HEIGHTAT 21200Z6 IS 15 FEET. NEXT WARNINGS AT 130300Z7 (DTG 130151Z1) AND 131500Z0 (DTG 131351Z4).// ========================================================================= WTXS31 PGTW 981113 03:00z 1. TROPICAL CYCLONE 04S (ALISON) WARNING NR 011 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 130000Z4 --- NEAR 18.2S1 89.8E5 MOVEMENT PAST SIX HOURS - 300 DEGREES AT 08 KTS POSITION ACCURATE TO WITHIN 120 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER REPEAT POSIT: 18.2S1 89.8E5 --- FORECASTS: 12 HRS, VALID AT: 131200Z7 --- 17.9S7 89.1E8 MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 130300Z7 POSITION NEAR 18.1S0 89.6E3. TROPICAL CYCLONE 04S (ALISON) HAS TRACKED WEST-NORTHWESTWARD AT 8 KNOTS OVER THE PAST 6 HOURS. THE WARNING POSITION AND INTENSITY ARE BASED UPON VISIBLE SATELLITE IMAGERY. TROPICAL CYCLONE 04S (ALISON) CAN NOT BE DISTINGUISHED ON ANIMATED INFRARED SATELLITE IMAGERY AS THE CONVECTION ASSOCIATED WITH THE LOW LEVEL CIRCULATION CENTER HAS SHEARED TO THE SOUTHEAST. TROPICAL CYCLONE 04S (ALISON) IS RAPIDLY DISSIPATING OVER WATER DUE TO THE AFOREMENTIONED HIGH SHEAR ENVIRONMENT. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 130000Z4 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: alison.htm
Updated: 26th December 2006 |
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