Tropical
Cyclones
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Tropical Cyclone BILLY [Australian Region][South Indian Ocean][South Pacific Ocean][Southern Hemisphere][Summaries and Track Data] |
WTXS21 PGTW 981202 08:00z SUBJ/TROPICAL CYCLONE FORMATION ALERT 020751Z DEC 98// RMKS/ 1. FORMATION OF A SIGNIFICANT TROPICAL CYCLONE IS POSSIBLE WITHIN 120 NM EITHER SIDE OF A LINE FROM 14.8S3 121.8E2 TO 18.0S9 117.1E0 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 20 TO 25 KNOTS. METSAT IMAGERY AT 020530Z INDICATES THAT A CIRCULATION CENTER IS LOCATED NEAR 15.4S0 120.6E9. THE SYSTEM IS MOVING SOUTH- SOUTHEASTWARD AT 09 KNOTS. 2. REMARKS: ANIMATED VISIBLE SATELLITE IMAGERY INDICATES THE AREA OFF THE NORTHWEST COAST OF AUSTRALIA HAS BECOME MORE ORGANIZED OVER THE PAST 12 HOURS. IN ADDITION, THE UPPER LEVEL ENVIRONMENT REMAINS FAVORABLE FOR FURTHER DEVELOPMENT. MINIMUM SEA LEVEL PRESSURE IS ESTIMATED TO BE 1004 MB. DUE TO THE INCREASED ORGANIZATION OVER THE PAST 12 HOURS AND THE FAVORABLE UPPER LEVEL ENVIRONMENT, THE POTENTIAL FOR THE DEVELOPMENT OF A SIGNIFICANT TROPICAL CYCLONE IS GOOD. 3. THIS ALERT VALID UNTIL 030800Z1.// ========================================================================= WTXS31 PGTW 981202 21:00z 1. TROPICAL CYCLONE 05S WARNING NR 001 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 021800Z1 --- NEAR 16.5S2 119.3E4 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 - 030 KT, GUSTS 040 KT REPEAT POSIT: 16.5S2 119.3E4 --- FORECASTS: 12 HRS, VALID AT: 030600Z9 --- 17.2S0 118.6E6 MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT VECTOR TO 24 HR POSIT: 225 DEG/ 05 KTS --- 24 HRS, VALID AT: 031800Z2 --- 17.9S7 117.9E8 MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT RADIUS OF 035 KT WINDS - 045 NM VECTOR TO 36 HR POSIT: 225 DEG/ 06 KTS --- 36 HRS, VALID AT: 040600Z0 --- 18.7S6 117.1E0 MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT RADIUS OF 035 KT WINDS - 050 NM SOUTHEAST SEMICIRCLE 045 NM ELSEWHERE VECTOR TO 48 HR POSIT: 225 DEG/ 06 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 041800Z3 --- 19.6S6 116.2E0 MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT RADIUS OF 035 KT WINDS - 055 NM SOUTHEAST SEMICIRCLE 045 NM ELSEWHERE --- REMARKS: 022100Z5 POSITION NEAR 16.7S4 119.1E2. TROPICAL CYCLONE 05S HAS DEVELOPED OFF THE NORTHWEST COAST OF AUSTRALIA. THE WARNING POSITION AND INTENSITY (30 KNOTS) ARE BASED ON 021130Z7 INFRARED SATELLITE IMAGERY. TROPICAL CYCLONE (TC) 05S DEVELOPED OVER THE PAST 24 HOURS FROM A DECAYING FRONTAL BOUNDARY/SHEAR LINE. SATELLITE ANIMATION SHOWS TC 05S HAS BECOME BETTER ORGANIZED AND HAS A FULLY EXPOSED LOW-LEVEL CIRCULATION CENTER. ANIMATION ALSO SHOWS CONVECTIVE BANDS NOW SPIRALING AROUND THE CENTER. SURFACE ANALYSIS INDICATES A DEEPENING CYCLONIC CIRCULATION WITH A CENTRAL PRESSURE OF ABOUT 1000MB. A 021026Z1 MICROWAVE IMAGER PASS ALSO INDICATED A CIRCULATION CENTER WITH CONVECTION WRAPPING ABOUT HALF WAY AROUND THE CENTER. UPPER-LEVEL ANALYSIS AND UNIVERSITY OF WISCONSIN WINDSHEAR PRODUCTS INDICATE FAVORABLE UPPER LEVEL DIVERGENCE AND WEAK VERTICAL WINDSHEAR OVER THE AREA. TC 05S SHOULD CONTINUE TO MOVE TOWARDS THE SOUTHWEST UNDER THE STEERING INFLUENCE OF THE HIGH PRESSURE RIDGE TO THE SOUTHEAST. TC 05S SHOULD CONTINUE TO SLOWLY INTENSIFY THROUGH THE PERIOD. AS IT CONTINUES TO MOVE FURTHER SOUTH, TC 05S SHOULD BEGIN TO EXPERIENCE SLIGHTLY INCREASED VERTICAL WINDSHEAR. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 021800ZZ1 IS 14 FEET. REFER TO WWIO31 PGFW FOR ADDITIONAL SEA HEIGHT INFORMATION.THIS WARNING SUPERSEDES AND CANCELS NAVPACMETOCCEN WEST GU 020751Z DEC 98 TROPICAL CYCLONE FORMATION ALERT (WTXS21 PGTW020800) NEXT WARNINGS AT 030300Z6 (DTG 030151Z0), 030900Z2 (DTG 030751Z6), 031500Z9 (DTG 031351Z3) AND 032100Z6 (DTG 031951Z9).// ========================================================================= WTXS31 PGTW 981203 03:00z 1. TROPICAL CYCLONE 05S WARNING NR 002 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 030000Z3 --- NEAR 17.2S0 118.7E7 MOVEMENT PAST SIX HOURS - 220 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 RADIUS OF 035 KT WINDS - 045 NM SOUTHEAST SEMICIRCLE 035 NM ELSEWHERE REPEAT POSIT: 17.2S0 118.7E7 --- FORECASTS: 12 HRS, VALID AT: 031200Z6 --- 18.5S4 117.6E5 MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT RADIUS OF 035 KT WINDS - 060 NM SOUTHEAST SEMICIRCLE 050 NM ELSEWHERE VECTOR TO 24 HR POSIT: 210 DEG/ 08 KTS --- 24 HRS, VALID AT: 040000Z4 --- 19.8S8 116.8E6 MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT RADIUS OF 035 KT WINDS - 070 NM SOUTHEAST SEMICIRCLE OVER WATER 055 NM ELSEWHERE OVER WATER VECTOR TO 36 HR POSIT: 195 DEG/ 08 KTS --- 36 HRS, VALID AT: 041200Z7 --- 21.4S7 116.3E1 MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND RADIUS OF 035 KT WINDS - 055 NM EAST SEMICIRCLE OVER WATER 045 NM ELSEWHERE OVER WATER VECTOR TO 48 HR POSIT: 170 DEG/ 09 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 050000Z5 --- 23.2S7 116.7E5 MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND RADIUS OF 035 KT WINDS - 035 NM OVER WATER VECTOR TO 72 HR POSIT: 140 DEG/ 09 KTS --- 72 HRS, VALID AT: 060000Z6 --- 26.1S9 119.3E4 MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND --- REMARKS: 030300Z6 POSITION NEAR 17.5S3 118.4E4. TROPICAL CYCLONE 05S HAS CONTINUED TRACKING TOWARDS THE SOUTHWEST AT 8 KNOTS. THE WARNING POSITION IS BASED UPON 022330Z0 VISIBLE AND INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED UPON SATELLITE CURRENT INTENSITY ESTIMATES OF 35 KNOTS AND A SUPPORTING SHIP REPORT. TC 05S IS FORECAST TO CONTINUE TO TRACK TOWARDS THE SOUTHWEST UNDER THE STEERING INFLUENCE OF THE SUBTROPICAL RIDGE TO ITS SOUTHEAST. THE FORECAST TRACK BECOMES MORE SOUTHWARD BETWEEN THE 24 TO 48 HOUR FORECAST PERIOD AS TC 05S BEGINS TO MOVE AROUND THE SUBTROPICAL RIDGE. TC 05S IS THEN FORECAST TO TURN MORE SOUTHEASTWARD AFTER THE 48 HOUR PERIOD IN RESPONSE TO AN APPROACHING TROUGH FROM THE WEST. AS TC 05S CONTINUES ON ITS FORECAST TRACK, THE SYSTEM SHOULD BEGIN TO UNDERGO INCREASED VERTICAL SHEAR. THEREFORE, THE SYSTEM IS EXPECTED TO SLOWLY INTENSIFY UNTIL MAKING LANDFALL PRIOR TO THE 36 HOUR FORECAST POSITION. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 030000Z3 IS 14 FEET. REFER TO WWIO31 PGFW FOR ADDITIONAL SEA HEIGHT INFORMATION. NEXT WARNINGS AT 030900Z2 (DTG 030751Z6), 031500Z9 (DTG 031351Z3), 032100Z6 (DTG 031951Z9) AND 040300Z7 (DTG 040151Z1).// ========================================================================= WTXS31 PGTW 981203 09:00z 1. TROPICAL CYCLONE 05S WARNING NR 003 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 030600Z9 --- NEAR 17.0S8 118.1E1 MOVEMENT PAST SIX HOURS - 280 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 RADIUS OF 035 KT WINDS - 060 NM SOUTH SEMICIRCLE 040 NM ELSEWHERE REPEAT POSIT: 17.0S8 118.1E1 --- FORECASTS: 12 HRS, VALID AT: 031800Z2 --- 16.9S6 117.1E0 MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT RADIUS OF 035 KT WINDS - 060 NM SOUTH SEMICIRCLE 040 NM ELSEWHERE VECTOR TO 24 HR POSIT: 255 DEG/ 06 KTS --- 24 HRS, VALID AT: 040600Z0 --- 17.2S0 115.9E6 MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT RADIUS OF 035 KT WINDS - 065 NM SOUTH SEMICIRCLE 055 NM ELSEWHERE VECTOR TO 36 HR POSIT: 235 DEG/ 07 KTS --- 36 HRS, VALID AT: 041800Z3 --- 18.0S9 114.6E2 MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT RADIUS OF 035 KT WINDS - 065 NM SOUTHEAST SEMICIRCLE 055 NM ELSEWHERE VECTOR TO 48 HR POSIT: 225 DEG/ 09 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 050600Z1 --- 19.2S2 113.3E8 MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER VECTOR TO 72 HR POSIT: 205 DEG/ 08 KTS --- 72 HRS, VALID AT: 060600Z2 --- 22.0S4 111.8E1 MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 030900Z2 POSITION NEAR 17.0S8 117.8E7. TROPICAL CYCLONE 05S HAS BEGUN TRACKING WESTWARD AT 6 KNOTS DURING THE PAST 6 HOURS. THE WARNING POSITION IS BASED UPON AN EARLIER 030038Z4 MICROWAVE IMAGER PASS AND 030530Z1 VISIBLE SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED UPON SATELLITE CURRENT INTENSITY ESTIMATES OF 35 KNOTS AND PREVIOUS SUPPORTING SHIP REPORTS. ANIMATED VISIBLE AND INFRARED SATELLITE IMAGERY INDICATE A SIGNIFICANTLY MORE WESTWARD TRACK THAN THAT OF THE PREVIOUS FORECAST. WEAKENED STEERING FLOW AND THE SYSTEM=S ASYMMETRIC STRUCTURE MAY BE RESPONSIBLE FOR THE SUDDEN TRACK CHANGE AND SLOWER MOVEMENT. TROPICAL CYCLONE 05S IS LOCATED BETWEEN THE SUBTROPICAL RIDGE TO ITS SOUTHEAST AND AN APPROACHING TROUGH TO ITS SOUTHWEST, CAUSING THE AFOREMENTIONED WEAKENED STEERING FLOW. TROPICAL CYCLONE 05S IS FORECAST TO CONTINUE ON THIS WESTWARD TRACK OVER THE NEXT 12 HOURS UNTIL RETURNING TO A MORE DOMINANT STEERING FLOW AHEAD OF THE TROUGH, RESULTING IN A MORE SOUTHWESTWARD TRACK AFTER THE 24 HOURS FORECAST POSITION. TROPICAL CYCLONE 05S IS EXPECTED TO BEGIN TO UNDERGO INCREASING SHEAR AS THE DOMINANT STEERING FLOW REINSTATES. THEREFORE, TROPICAL CYCLONE 05S IS FORECAST TO STRENGTHEN ONLY SLIGHTLY THROUGHOUT THE 36 HOUR FORECAST PERIOD, THEN IS EXPECTED TO BEGIN TO DISSIPATE OVER WATER THROUGHOUT THE REMAINDER OF THE FORECAST PERIOD. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 030600Z IS 14 FEET. REFER TO WWIO30 PGFW FOR ADDITIONAL SEA HEIGHT INFORMATION. NEXT WARNINGS AT 031500Z9 (DTG 031351Z3), 032100Z6 (DTG 031951Z9), 040300Z7 (DTG 040151Z1) AND 040900Z3 (DTG 040751Z7).// ========================================================================= WTXS31 PGTW 981203 21:00z 1. TROPICAL CYCLONE 05S (BILLY) WARNING NR 005 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 031800Z2 --- NEAR 17.5S3 117.4E3 MOVEMENT PAST SIX HOURS - 250 DEGREES AT 03 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 - 065 NM SOUTH SEMICIRCLE 045 NM ELSEWHERE REPEAT POSIT: 17.5S3 117.4E3 --- FORECASTS: 12 HRS, VALID AT: 040600Z0 --- 17.8S6 116.8E6 MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT RADIUS OF 035 KT WINDS - 075 NM SOUTH SEMICIRCLE 060 NM ELSEWHERE VECTOR TO 24 HR POSIT: 240 DEG/ 05 KTS --- 24 HRS, VALID AT: 041800Z3 --- 18.3S2 115.9E6 MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT RADIUS OF 035 KT WINDS - 080 NM SOUTH SEMICIRCLE 070 NM ELSEWHERE VECTOR TO 36 HR POSIT: 235 DEG/ 06 KTS --- 36 HRS, VALID AT: 050600Z1 --- 19.0S0 114.9E5 MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT RADIUS OF 035 KT WINDS - 075 NM SOUTHEAST SEMICIRCLE 060 NM ELSEWHERE VECTOR TO 48 HR POSIT: 225 DEG/ 07 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 051800Z4 --- 20.0S2 113.9E4 MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT RADIUS OF 035 KT WINDS - 070 NM SOUTHEAST SEMICIRCLE 055 NM ELSEWHERE VECTOR TO 72 HR POSIT: 210 DEG/ 07 KTS --- 72 HRS, VALID AT: 061800Z5 --- 22.6S0 112.4E8 MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT RADIUS OF 035 KT WINDS - 065 NM EAST SEMICIRCLE 045 NM ELSEWHERE --- REMARKS: 032100Z6 POSITION NEAR 17.6S4 117.3E2. TROPICAL CYCLONE 05S (BILLY) HAS BEEN TRACKING WEST-SOUTHWESTWARD AT 3 KNOTS OVER THE PAST 6 HOURS. THE WARNING POSITION IS BASED ON 031730Z4 INFRARED SATELLITE IMAGERY. THE WARNING INTENSITY IS BASED ON 031730Z4 SATELLITE INTENSITY ESTIMATES OF 45 KNOTS. TROPICAL CYCLONE 05S (BILLY) HAS BEEN MOVING SLOWLY WEST- SOUTHWESTWARD IN THE STEERING FLOW FROM THE SUBTROPICAL RIDGE TO ITS SOUTH. THIS STEERING SHOULD REMAIN THE DOMINANT STEERING INFLUENCE THROUGHOUT THE FORECAST PERIOD. TROPICAL CYCLONE 05S (BILLY) IS FORECAST TO MOVE WEST-SOUTHWESTWARD AND THEN SOUTHWESTWARD AS THE RIDGE GRADUALLY WEAKENS DUE TO AN APPROACHING MID- LATITUDE TROUGH. TROPICAL CYCLONE 05S (BILLY) IS FORECAST TO CONTINUE TO INTENSIFY UNTIL THE 24-HOUR TRACK POSITION AT WHICH TIME THE SYSTEM SHOULD BEGIN TO ENCOUNTER INCREASING VERTICAL WIND SHEAR. ENHANCED INFRARED IMAGERY AND MICROWAVE IMAGERY SHOW THE DEEP CONVECTION ASSOCIATED WITH TROPICAL CYCLONE 05S (BILLY) IS LOCATED WEST OF THE LOW-LEVEL CIRCULATION CENTER SUGGESTING THE SYSTEM IS BEGINNING TO EXPERIENCE INCREASING WIND SHEAR AS IT MOVES AGAINST THE SUBTROPICAL RIDGE. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 031800Z IS 15 FEET. NEXT WARNINGS AT 040300Z7 (DTG 040151Z1), 040900Z3 (DTG 040751Z7), 041500Z0 (DTG 041351Z4) AND 042100Z7 (DTG 041951Z0).// ========================================================================= warning 006 not available ========================================================================= WTXS31 PGTW 981204 09:00z 1. TROPICAL CYCLONE 05S (BILLY) WARNING NR 007 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 040600Z0 --- NEAR 18.5S4 116.6E4 MOVEMENT PAST SIX HOURS - 225 DEGREES AT 04 KTS POSITION ACCURATE TO WITHIN 045 NM POSITION BASED ON CENTER LOCATED BY A COMBINATION OF SATELLITE AND RADAR PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 065 KT, GUSTS 080 KT RADIUS OF 050 KT WINDS - 025 NM SOUTHEAST SEMICIRCLE 020 NM ELSEWHERE RADIUS OF 035 KT WINDS - 065 NM SOUTHEAST SEMICIRCLE 050 NM ELSEWHERE REPEAT POSIT: 18.5S4 116.6E4 --- FORECASTS: 12 HRS, VALID AT: 041800Z3 --- 19.3S3 115.8E5 MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT RADIUS OF 050 KT WINDS - 020 NM SOUTHEAST SEMICIRCLE 015 NM ELSEWHERE RADIUS OF 035 KT WINDS - 070 NM SOUTHEAST SEMICIRCLE 055 NM ELSEWHERE VECTOR TO 24 HR POSIT: 210 DEG/ 09 KTS --- 24 HRS, VALID AT: 050600Z1 --- 20.8S0 114.9E5 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 - 075 NM SOUTHEAST SEMICIRCLE OVER WATER 055 NM ELSEWHERE OVER WATER VECTOR TO 36 HR POSIT: 205 DEG/ 09 KTS --- 36 HRS, VALID AT: 051800Z4 --- 22.5S9 114.1E7 MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND RADIUS OF 035 KT WINDS - 065 NM SOUTHEAST SEMICIRCLE OVER WATER 050 NM ELSEWHERE OVER WATER VECTOR TO 48 HR POSIT: 215 DEG/ 07 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 060600Z2 --- 23.6S1 113.3E8 MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 035 KT WINDS - 050 NM SOUTHEAST SEMICIRCLE OVER WATER 035 NM ELSEWHERE OVER WATER VECTOR TO 72 HR POSIT: 225 DEG/ 06 KTS --- 72 HRS, VALID AT: 070600Z3 --- 25.3S0 111.3E6 MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 040900Z3 POSITION NEAR 18.7S6 116.4E2. TROPICAL CYCLONE 05S (BILLY) HAS TRACKED SOUTHWESTWARD AT 04 KNOTS THE PAST 06 HOURS. THE WARNING POSITION IS BASED UPON A COMBINATION OF 040640Z4 RADAR IMAGERY FROM WMO NUMBER 94308 (DAMPIER, AUSTRALIA) AND ANALYSIS OF 04530Z2 VISIBLE SATELLITE IMAGERY. RADAR IMAGERY STILL INDICATES THE THE PRESENCE OF A 13NM DIAMETER EYE. ANIMATED SATELLITE IMAGERY SUGGESTS THAT VERTICAL WIND SHEAR HAS BEGUN TO AFFECT THE SYSTEM OVER THE PAST SEVERAL HOURS AS THE EYE FEATURE IS NO LONGER DISCERNABLE DUE TO CIRRUS CLOUD COVER. WITH STRONGER WEST- NORTHWESTERLY WINDS LOCATED TO THE SOUTH, IT APPEARS THAT THE SYSTEM HAS PEAKED AND WILL BEGIN WEAKENING SOON DUE TO THE INCREASING VERTICAL WIND SHEAR. THIS WEAKENING TREND WILL CONTINUE THROUGH THE REMAINDER OF THE FORECAST PERIOD. WITH THE EXCEPTION OF SOME SLIGHTLY SLOWER FORWARD MOTION SPEEDS, THERE IS NO SIGNIFICANT CHANGE TO THE FORECAST TRACK AND INTENSITY PHILOSOPHY. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 040600Z IS 14 FEET. REFER TO WWPIO30 PGFW FOR ADDITIONAL SEA HEIGHT INFORMATION. NEXT WARNINGS AT 041500Z0 (DTG 041351Z4), 042100Z7 (DTG 041951Z0), 050300Z8 (DTG 050151Z2) AND 050900Z4 (DTG 050751Z8).// ========================================================================= WTXS31 PGTW 981204 15:00z 1. TROPICAL CYCLONE 05S (BILLY) WARNING NR 008 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 041200Z7 --- NEAR 18.9S8 116.4E2 MOVEMENT PAST SIX HOURS - 205 DEGREES AT 04 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 - 025 NM SOUTHEAST SEMICIRCLE 020 NM ELSEWHERE RADIUS OF 035 KT WINDS - 075 NM SOUTHEAST SEMICIRCLE 060 NM ELSEWHERE REPEAT POSIT: 18.9S8 116.4E2 --- FORECASTS: 12 HRS, VALID AT: 050000Z5 --- 19.7S7 116.0E8 MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT RADIUS OF 050 KT WINDS - 020 NM SOUTHEAST SEMICIRCLE 015 NM ELSEWHERE RADIUS OF 035 KT WINDS - 075 NM SOUTHEAST SEMICIRCLE OVER WATER 060 NM ELSEWHERE OVER WATER VECTOR TO 24 HR POSIT: 200 DEG/ 06 KTS --- 24 HRS, VALID AT: 051200Z8 --- 20.8S0 115.6E3 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 OVER WATER 055 NM ELSEWHERE OVER WATER VECTOR TO 36 HR POSIT: 205 DEG/ 06 KTS --- 36 HRS, VALID AT: 060000Z6 --- 21.9S2 115.1E8 MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT RADIUS OF 035 KT WINDS - 065 NM SOUTHEAST SEMICIRCLE OVER WATER 050 NM ELSEWHERE OVER WATER VECTOR TO 48 HR POSIT: 210 DEG/ 06 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 061200Z9 --- 22.9S3 114.5E1 MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT RADIUS OF 035 KT WINDS - 055 NM SOUTHEAST SEMICIRCLE OVER WATER 045 NM ELSEWHERE OVER WATER VECTOR TO 72 HR POSIT: 215 DEG/ 05 KTS --- 72 HRS, VALID AT: 071200Z0 --- 24.5S1 113.3E8 MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 041500Z0 POSITION NEAR 19.1S1 116.3E1. TROPICAL CYCLONE 05S (BILLY) HAS BEEN TRACKING SOUTH-SOUTHWESTWARD AT 4 KNOTS OVER THE PAST 6 HOURS. THE WARNING POSITION IS BASED ON 041130Z9 INFRARED SATELLITE IMAGERY, EXTRAPOLATION FROM A 040949Z6 MICROWAVE IMAGER PASS AND ANIMATION. THE WARNING INTENSITY IS BASED ON 041130Z9 SATELLITE INTENSITY ESTIMATE OF 65 KNOTS. TROPICAL CYCLONE 05S (BILLY) HAS PEAKED IN INTENSITY OVER THE PAST 12 HOURS AND THE SYSTEM IS NO LONGER DISPLAYING AN EYE FEATURE. TROPICAL CYCLONE 05S (BILLY) IS SLOWLY MOVING SOUTH- SOUTHWESTWARD IN THE STEERING FLOW FROM THE SUBTROPICAL RIDGE TO ITS SOUTH-SOUTHEAST AND THE MID-LATITUDE TROUGH TO ITS SOUTHWEST. TROPICAL CYCLONE 05S (BILLY) IS FORECAST TO MAKE LANDFALL AFTER THE 24-HOUR TRACK POSITION. ANIMATED INFRARED IMAGERY SHOWS THE SYSTEM=S DEEP CONVECTION IS BEGINNING TO BE CARRIED SOUTHWARD IN THE MID- LEVEL STEERING FLOW. TROPICAL CYCLONE 05S (BILLY) IS FORECAST TO CONTINUE SOUTH-SOUTHWESTWARD THROUGHOUT THE 36-HOUR FORECAST TRACK POSITION, SLOWLY WEAKENING AS IT ENCOUNTERS INCREASING VERTICAL WIND SHEAR. AFTER THE 36-HOUR TRACK POSITION, THE WEAKENING SYSTEM WILL BEGIN TO MOVE MORE WESTWARD AS IT BEGINS TO BECOME MORE INFLUENCED BY THE LOW LEVEL STEERING FLOW. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 041200Z IS 14 FEET. NEXT WARNINGS AT 042100Z7 (DTG 041951Z0), 050300Z8 (DTG 050151Z2), 050900Z4 (DTG 050751Z8) AND 051500Z1 (DTG 051351Z5).// ========================================================================= WTXS31 PGTW 981204 21:00z 1. TROPICAL CYCLONE 05S (BILLY) WARNING NR 009 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 041800Z3 --- NEAR 18.9S8 116.4E2 MOVEMENT PAST SIX HOURS - 180 DEGREES AT 02 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 SOUTHEAST SEMICIRCLE 020 NM ELSEWHERE RADIUS OF 035 KT WINDS - 075 NM SOUTHEAST SEMICIRCLE 070 NM ELSEWHERE REPEAT POSIT: 18.9S8 116.4E2 --- FORECASTS: 12 HRS, VALID AT: 050600Z1 --- 19.6S6 116.1E9 MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT RADIUS OF 050 KT WINDS - 020 NM SOUTHEAST SEMICIRCLE 015 NM ELSEWHERE RADIUS OF 035 KT WINDS - 075 NM SOUTHEAST SEMICIRCLE OVER WATER 070 NM ELSEWHERE OVER WATER VECTOR TO 24 HR POSIT: 200 DEG/ 05 KTS --- 24 HRS, VALID AT: 051800Z4 --- 20.6S8 115.7E4 MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT RADIUS OF 035 KT WINDS - 065 NM SOUTHEAST SEMICIRCLE OVER WATER 060 NM ELSEWHERE OVER WATER VECTOR TO 36 HR POSIT: 195 DEG/ 06 KTS --- 36 HRS, VALID AT: 060600Z2 --- 21.8S1 115.3E0 MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT RADIUS OF 035 KT WINDS - 055 NM SOUTHEAST SEMICIRCLE OVER WATER 050 NM ELSEWHERE OVER WATER VECTOR TO 48 HR POSIT: 210 DEG/ 06 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 061800Z5 --- 22.8S2 114.7E3 MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT RADIUS OF 035 KT WINDS - 050 NM SOUTHEAST SEMICIRCLE OVER WATER 045 NM ELSEWHERE OVER WATER VECTOR TO 72 HR POSIT: 215 DEG/ 06 KTS --- 72 HRS, VALID AT: 071800Z6 --- 24.7S3 113.3E8 MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 042100Z7 POSITION NEAR 19.1S1 116.3E1. TROPICAL CYCLONE 05S (BILLY) HAS BEEN DRIFTING SOUTHWARD AT 2 KNOTS OVER THE PAST 6 HOURS. THE WARNING POSITION IS BASED ON 041730Z5 INFRARED SATELLITE IMAGERY AND EXTRAPOLATION FROM A 041318Z7 MICROWAVE IMAGER PASS. THE WARNING INTENSITY OF 60 KNOTS IS BASED ON AN AVERAGE OF 041730Z5 SATELLITE INTENSITY ESTIMATES. TROPICAL CYCLONE 05S (BILLY)IS DRIFTING SLOWLY SOUTHWARD IN THE STEERING FLOW FROM THE SUBTROPICAL RIDGE TO ITS SOUTHEAST. ANIMATED SATELLITE IMAGERY SHOWS THE SYSTEM BEGINNING TO ELONGATE AS THE DEEP CONVECTION MOVES SOUTHWARD. TROPICAL CYCLONE 05S (BILLY)=S LOW-LEVEL IS DIFFICULT TO LOCATE USING INFRARED IMAGERY AND THE WARNING POSITION WAS EXTRAPOLATED FROM A MICROWAVE IMAGER PASS WHICH SHOWED THE LOW-LEVEL NORTH OF THE DEEP CONVECTION. TROPICAL CYCLONE 05S (BILLY) IS FORECAST TO CONTINUE MOVING SOUTHWARD AND SOUTHWESTWARD IN THE MID-LEVEL STEERING FLOW AND IS FORECAST TO MAKE LANDFALL AFTER THE 24-HOUR TRACK POSITION. TROPICAL CYCLONE 05S (BILLY) HAS WEAKENED OVER THE PAST 6 HOURS. AS THE SYSTEM MOVES SOUTHWARD IT WILL CONTINUE TO ENCOUNTER INCREASING VERTICAL WIND SHEAR, AS WELL AS LAND INTERACTION AFTER IT MAKES LANDFALL, WHICH WILL FURTHER WEAKEN THE SYSTEM. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 041800Z IS 14 FEET. NEXT WARNINGS AT 050300Z8 (DTG 050151Z2), 050900Z4 (DTG 050751Z8), 051500Z1 (DTG 051351Z5) AND 052100Z8 (DTG 051951Z1).// ========================================================================= WTXS31 PGTW 981205 03:00z SUBJ: TROPICAL CYCLONE WARNING 1. TROPICAL CYCLONE 05S (BILLY) WARNING NR 010 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 050000Z5 --- NEAR 19.4S4 116.4E2 MOVEMENT PAST SIX HOURS - 180 DEGREES AT 03 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 SOUTHEAST SEMICIRCLE 020 NM ELSEWHERE RADIUS OF 035 KT WINDS - 075 NM SOUTHEAST SEMICIRCLE OVER WATER 070 NM ELSEWHERE REPEAT POSIT: NEAR 19.4S4 116.4E2 --- FORECASTS: 12 HRS, VALID AT: 051200Z8 --- 20.2S4 116.3E1 MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT RADIUS OF 035 KT WINDS - 065 NM SOUTHEAST SEMICIRCLE OVER WATER 060 NM ELSEWHERE VECTOR TO 24 HR POSIT: 190 DEG/ 04 KTS --- 24 HRS, VALID AT: 060000Z6 --- 20.9S1 116.2E0 MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT RADIUS OF 035 KT WINDS - 055 NM SOUTHEAST SEMICIRCLE OVER WATER 045 NM ELSEWHERE VECTOR TO 36 HR POSIT: 200 DEG/ 04 KTS --- 36 HRS, VALID AT: 061200Z9 --- 21.7S0 115.9E6 MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND VECTOR TO 48 HR POSIT: 195 DEG/ 04 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 070000Z7 --- 22.5S9 115.7E4 MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND --- REMARKS: 050300Z8 POSITION NEAR 19.6S6 116.4E2. TROPICAL CYCLONE 05S (BILLY) HAS TRACKED SOUTHWARD AT 3 KNOTS OVER THE PAST 6 HOURS. THE WARNING POSITION IS BASED UPON 042330Z2 INFRARED SATELLITE IMAGE, AND THE WARNING INTENSITY IS BASED UPON A SATELLITE CURRENT INTENSITY ESTIMATE OF 65 KNOTS AS WELL AS CONTINUITY WITH THE PREVIOUS FORECAST. ANIMATED WATER VAPOR SATELLITE IMAGERY CONTINUES TO SHOW THAT TC 05S (BILLY) IS UNDERGOING MODERATE TO STRONG UPPER LEVEL WIND SHEAR. ALTHOUGH TC 05S (BILLY) CONTINUES TO BE STEERED BY THE HIGH PRESSURE SYSTEM TO ITS SOUTHEAST, THE HIGH PRESSURE SYSTEM IS FORECAST TO CHANGE ITS ORIENTATION TO ALLOW FOR THE MORE SOUTHWARDLY TRACK. DUE TO THE HIGH SHEAR ENVIRONMENT, TC 05S (BILLY) SHOULD NOT INTENSIFY AS IT APPROACHES LANDFALL AND SHOULD RAPIDLY DISSIPATE AS IT TRACKS OVER THE NORTHERN COAST OF AUSTRALIA BY THE 24 HOUR FORECAST POSITION. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 050000Z5 IS 14 FEET. NEXT WARNINGS AT 050900Z4 (DTG 050751Z8), 051500Z1 (DTG 051351Z5), 052100Z8 (DTG 051951Z1) AND 060300Z9 (DTG 060151Z3).// ========================================================================= WTXS31 PGTW 050900 SUBJ: TROPICAL CYCLONE WARNING 1. TROPICAL CYCLONE 05S (BILLY) WARNING NR 011 01 ACTIVE TROPICAL CYCLONE IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 050600Z1 --- NEAR 19.5S5 115.3E0 MOVEMENT PAST SIX HOURS - 225 DEGREES AT 03 KTS POSITION ACCURATE TO WITHIN 045 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 060 KT, GUSTS 075 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 050 KT WINDS - 025 NM SOUTHEAST SEMICIRCLE 020 NM ELSEWHERE RADIUS OF 035 KT WINDS - 075 NM SOUTHEAST SEMICIRCLE 070 NM ELSEWHERE REPEAT POSIT: NEAR 19.5S5 115.3E0 --- FORECASTS: 12 HRS, VALID AT: 051800Z4 --- 19.9S9 114.9E5 MAX SUSTAINED WINDS - 050 KT, GUSTS 065 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 035 KT WINDS - 065 NM SOUTHEAST SEMICIRCLE 060 NM ELSEWHERE VECTOR TO 24 HR POSIT: 195 DEG/ 04 KTS --- 24 HRS, VALID AT: 060600Z2 --- 20.6S8 114.7E3 MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 035 KT WINDS - 055 NM SOUTHEAST SEMICIRCLE 045 NM ELSEWHERE VECTOR TO 36 HR POSIT: 180 DEG/ 03 KTS --- 36 HRS, VALID AT: 061800Z5 --- 21.1S4 114.6E2 MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 035 KT WINDS - 055 NM SOUTHEAST SEMICIRCLE OVER WATER 045 NM ELSEWHERE VECTOR TO 48 HR POSIT: 180 DEG/ 03 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 070600Z3 --- 21.8S1 114.5E1 MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND RADIUS OF 035 KT WINDS - 040 NM OVER WATER VECTOR TO 72 HR POSIT: 185 DEG/ 04 KTS --- 72 HRS, VALID AT: 080600Z4 --- 23.2S7 114.3E9 MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND --- REMARKS: 050900Z4 POSITION NEAR 19.6S6 115.2E9. TROPICAL CYCLONE 05S (BILLY) HAS TRACKED SOUTHWESTWARD AT 03 KNOTS OVER THE PAST 6 HOURS. THE WARNING POSITION IS BASED UPON A 050530Z3 VISIBLE SATELLITE IMAGE, AND THE WARNING INTENSITY IS BASED UPON A CURRENT INTENSITY ESTIMATE OF 65 KNOTS BUT TAKES INTO ACCOUNT THE INCREASED SHEAR ENVIRONMENT. THE CURRENT POSITION OF TC 05S (BILLY) HAS BEEN LOCATED FURTHER WEST FROM THE PREVIOUS FORECAST DUE TO THE VISIBLE SATELLITE IMAGERY. THE ANIMATED VISIBLE SATELLITE IMAGERY SHOWS TC 05S (BILLY) CONTINUES TO BE UNDER MODERATE TO HIGH VERTICAL WIND SHEAR AS MOST OF THE CONVECTION HAS SHEARED AWAY TO THE SOUTHEAST. TROPICAL CYCLONE 05S (BILLY) SHOULD COUNTINUE TO DISSIPATE AS IT APPROACHES THE NORTHWEST COAST OF AUSTRALIA DUE TO THE INCREASED SHEAR ENVIRONMENT. AFTER MAKING LANDFALL, TC 05S (BILLY) SHOULD DISSIPATE EVEN MORE RAPIDLY. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 050600Z IS 14 FEET. NEXT WARNINGS AT 051500Z1 (DTG 051351Z5), 052100Z8 (DTG 051951Z1), 060300Z9 (DTG 060151Z3) AND 060900Z5 (DTG 060751Z9).// ========================================================================= WTXS31 PGTW 981205 15:00z 1. TROPICAL CYCLONE 05S (BILLY) WARNING NR 012 02 ACTIVE TROPICAL CYCLONES IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 051200Z8 --- NEAR 20.1S3 115.2E9 MOVEMENT PAST SIX HOURS - 190 DEGREES AT 05 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 SOUTHEAST SEMICIRCLE 040 NM ELSEWHERE REPEAT POSIT: NEAR 20.1S3 115.2E9 --- FORECASTS: 12 HRS, VALID AT: 060000Z6 --- 21.1S4 114.9E5 MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 035 KT WINDS - 040 NM SOUTHEAST SEMICIRCLE OVER WATER 030 NM ELSEWHERE OVER WATER VECTOR TO 24 HR POSIT: 190 DEG/ 05 KTS --- 24 HRS, VALID AT: 061200Z9 --- 22.1S5 114.7E3 MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND VECTOR TO 36 HR POSIT: 180 DEG/ 05 KTS --- 36 HRS, VALID AT: 070000Z7 --- 23.1S6 114.6E2 MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND VECTOR TO 48 HR POSIT: 180 DEG/ 06 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 071200Z0 --- 24.2S8 114.6E2 MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND --- REMARKS: 051500Z1 POSITION NEAR 20.4S6 115.1E8. TROPICAL CYCLONE 05S (BILLY) HAS TRACKED SOUTHWARD AT 05 KNOTS OVER THE PAST 6 HOURS. THE WARNING POSITION AND CURRENT INTENSITY (45KTS) ARE BASED ON A COMBINATION OF 051130Z0 INFRARED SATELLITE IMAGE ANALYSIS TECHNIQUES (55KTS) AND SCATTEROMETRY DATA (45 KTS). THE MICROWAVE SCATTEROMETER PASS (050220Z9) INDICATED THE SYSTEM HAS WEAKENED CONSIDERABLY IN THE PAST 12 HOURS. ANIMATED SATELLITE IMAGERY ALSO REVEALS A FLARE-UP OF DEEP CONVECTION AROUND THE SYSTEM OVER THE LAST THREE HOURS. THIS INCREASE IN CONVECTION AROUND THE CENTER INDICATES A TEMPORARY WEAKENING OF VERTICAL WINDSHEAR. UW CIMSS WINDSHEAR PRODUCTS ALSO SHOW TC 05S (BILLY) IS MOVING INTO AN AREA OF MODERATE VERTICAL WIND SHEAR. TC 05S (BILLY) SHOULD CONTINUE TO SLOWLY TRACK SOUTHWARD UNDER THE INFLUENCE OF THE SUBTROPICAL RIDGE TO THE SOUTHEAST. TROPICAL CYCLONE 05S (BILLY) SHOULD ALSO COUNTINUE TO WEAKEN AS IT APPROACHES THE NORTHWEST COAST OF AUSTRALIA DUE TO THE INCREASED WINDSHEAR ENVIRONMENT. AFTER MAKING LANDFALL, TC 05S (BILLY) SHOULD DISSIPATE EVEN MORE RAPIDLY DUE TO LAND INTERACTION. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 051200Z8 IS 14 FEET. REFER TO WWIO31 PGFW FOR ADDITIONAL SEA HEIGHT INFORMATION. NEXT WARNINGS AT 052100Z8 (DTG 051951Z1), 060300Z9 (DTG 060151Z3), 060900Z5 (DTG 060751Z9) AND 061500Z2 (DTG 061351Z6).REFER TO TROPICAL CYCLONE 06S (NONAME) WARNINGS (WTXS32 PGTW) FOR SIX-HOURLY UPDATES.// ========================================================================= WTXS31 PGTW 981205 21:00z COR 1. TROPICAL CYCLONE 05S (BILLY) WARNING NR 013 CORRECTED 02 ACTIVE TROPICAL CYCLONES IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 051800Z4 --- NEAR 20.3S5 115.0E7 MOVEMENT PAST SIX HOURS - 180 DEGREES AT 02 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 SOUTHEAST SEMICIRCLE 040 NM ELSEWHERE REPEAT POSIT: 20.3S5 115.0E7 --- FORECASTS: 12 HRS, VALID AT: 060600Z2 --- 20.8S0 114.8E4 MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 035 KT WINDS - 040 NM SOUTHEAST SEMICIRCLE 030 NM ELSEWHERE VECTOR TO 24 HR POSIT: 200 DEG/ 03 KTS --- 24 HRS, VALID AT: 061800Z5 --- 21.3S6 114.6E2 MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER VECTOR TO 36 HR POSIT: 180 DEG/ 04 KTS --- 36 HRS, VALID AT: 070600Z3 --- 22.0S4 114.5E1 MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND VECTOR TO 48 HR POSIT: 180 DEG/ 04 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 071800Z6 --- 22.9S3 114.4E0 MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND VECTOR TO 72 HR POSIT: 180 DEG/ 05 KTS --- 72 HRS, VALID AT: 081800Z7 --- 24.8S4 114.3E9 MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND --- REMARKS: 052100Z8 POSITION NEAR 20.4S6 115.0E7. TROPICAL CYCLONE 05S (BILLY) HAS DRIFTED SOUTHWARD AT 02 KNOTS OVER THE PAST 6 HOURS. THE WARNING POSITION AND CURRENT INTENSITY (45KTS) ARE BASED ON 051730Z6 INFRARED SATELLITE IMAGE ANALYSIS TECHNIQUES AND A MICROWAVE IMAGER PASS (051253Z6). ANIMATED SATELLITE IMAGERY INDICATES THE SYSTEM HAS BECOME QUASI-STATIONARY OVER THE PAST 6 HOURS. THE MICROWAVE PASS INDICATES THE LOW-LEVEL CIRCULATION CENTER HAS BECOME EXPOSED. THIS EXPOSURE WOULD INDICATE AN INCREASE IN VERTICAL WINDSHEAR. SYNOPTIC WIND REPORTS FROM BARROW=S ISLAND AUSTRALIA (WMO 94304) OVER THE PAST SEVERAL HOURS INDICATE THE SYSTEM IS IS QUASI-STATIONARY. UW CIMSS WINDSHEAR PRODUCTS AND ANIMATED WATER VAPOR IMAGERY INDICATE TC 05S (BILLY) IS MOVING INTO AN AREA OF MODERATE VERTICAL WINDSHEAR. ANIMATION ALSO REVEALS SEVERAL OUTFLOW BOUNDARIES FROM THUNDERSTORMS INTERSECTING IN THE VICINITY OF THE SYSTEM. TC 05S (BILLY) IS FORECAST TO CONTINUE TO DRIFT SOUTHWARD WITH THE LOW-MID LEVEL STEERING FLOW OF THE SUBTROPICAL RIDGE TO THE SOUTH. TROPICAL CYCLONE 05S (BILLY) SHOULD ALSO COUNTINUE TO WEAKEN AS IT APPROACHES THE NORTHWEST COAST OF AUSTRALIA DUE TO THE INCREASED WINDSHEAR ENVIRONMENT. AFTER MAKING LANDFALL, TC 05S (BILLY) SHOULD DISSIPATE EVEN MORE RAPIDLY DUE TO LAND INTERACTION. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 051800Z4 IS 14 FEET. NEXT WARNINGS AT 060300Z9 (DTG 060151Z3), 060900Z5 (DTG 060751Z9), 061500Z2 (DTG 061351Z6) AND 062100Z9 (DTG 061951Z2). REFER TO TROPICAL CYCLONE 06S WARNINGS (WTXS32 PGTW) FOR TWELVE-HOURLY UPDATES. 2. JUSTIFICATION FOR CORRECTION: TO REMOVE REFERENCE TO WWIO31 AND CHANGE TROPICAL CYCLONE 06S TO REFLECT 12 HOUR WARNINGS IN THE REMARKS SECTION.// ========================================================================= WTXS31 PGTW 981206 03:00z SUBJ: TROPICAL CYCLONE WARNING 1. TROPICAL CYCLONE 05S (BILLY) WARNING NR 014 02 ACTIVE TROPICAL CYCLONES IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 060000Z6 --- NEAR 20.8S0 114.9E5 MOVEMENT PAST SIX HOURS - 180 DEGREES AT 04 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 035 KT WINDS - 040 NM SOUTHEAST SEMICIRCLE 030 NM ELSEWHERE REPEAT POSIT: NEAR 20.8S0 114.9E5 --- FORECASTS: 12 HRS, VALID AT: 061200Z9 --- 21.3S6 114.8E4 MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER VECTOR TO 24 HR POSIT: 195 DEG/ 03 KTS --- 24 HRS, VALID AT: 070000Z7 --- 21.9S2 114.6E2 MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND VECTOR TO 36 HR POSIT: 180 DEG/ 04 KTS --- 36 HRS, VALID AT: 071200Z0 --- 22.8S2 114.5E1 MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND --- REMARKS: 060300Z9 POSITION NEAR 20.9S1 114.9E5. TROPICAL CYCLONE 05S (BILLY) HAS TRACKED SOUTHWARD AT 4 KNOTS OVER THE PAST 6 HOURS. THE WARNING POSITION IS BASED UPON A 052330Z3 VISIBLE SATELLITE IMAGE. THE WARNING INTENSITY IS BASED UPON A COMBINATION OF A SATELLITE CURRENT INTENSITY ESTIMATE OF 35 KNOTS AND CONTINUITY WITH THE PREVIOUS FORECAST. TROPICAL CYCLONE 05S (BILLY) CONTINUES TO TRACK SLOWLY SOUTHWARD TOWARDS THE NORTHWEST COAST OF AUSTRALIA NEAR PORT EXMOUTH. ALTHOUGH THE STEERING INFLUENCE REMAINS THE HIGH PRESSURE SYSTEM TO THE SOUTHEAST, TC 05S (BILLY) IS IN AN AREA WITH LIGHT LOW LEVEL STEERING, WHICH ACCOUNTS FOR ITS SLOW MOVEMENT. IN ADDITION, THE 0512000Z8 UW-CIMSS WATER VAPOR/WIND SHEAR CHARTS INDICATE TC 05S (BILLY) IS UNDERGOING MODERATE TO SEVERE UPPER LEVEL WIND SHEAR. INDEED, SATELLITE ANALYSIS CONFIRMS THE LOW LEVEL CIRCULATION IS ALMOST TOTALLY EXPOSED. SINCE THE CONVECTION HAS BLOWN AWAY FROM THE LOW LEVEL CIRCULATION, TC 05S (BILLY) IS DISSIPATING RAPIDLY OVER WATER. TROPICAL CYCLONE 05S (BILLY) WILL CONTINUE TO DISSIPATE UNTIL IT STRIKES LAND BY THE 24 HOUR FORECAST POSITION. AT THAT TIME, TC 05S (BILLY) WILL DISSIPATE OVER THE AUSTRALIAN MAINLAND. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 060000Z6 IS 12 FEET. NEXT WARNINGS AT 060900Z5 (DTG 060751Z9), 061500Z2 (DTG 061351Z6), 062100Z9 (DTG 061951Z2) AND 070300Z0 (DTG 070151Z4). REFER TO TROPICAL CYCLONE 06S WARNINGS (WTXS32 PGTW) FOR TWELVE-HOURLY UPDATES.// ========================================================================= WTXS31 PGTW 981206 09:00z SUBJ: TROPICAL CYCLONE WARNING 1. TROPICAL CYCLONE 05S (BILLY) WARNING NR 015 02 ACTIVE TROPICAL CYCLONES IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 060600Z2 --- NEAR 21.5S8 115.0E7 MOVEMENT PAST SIX HOURS - 180 DEGREES AT 05 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 DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER REPEAT POSIT: NEAR 21.5S8 115.0E7 --- FORECASTS: 12 HRS, VALID AT: 061800Z5 --- 22.3S7 115.1E8 MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND VECTOR TO 24 HR POSIT: 160 DEG/ 03 KTS --- 24 HRS, VALID AT: 070600Z3 --- 22.8S2 115.3E0 MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND --- REMARKS: 060900Z5 POSITION NEAR 21.7S0 115.0E7. TROPICAL CYCLONE 05S (BILLY) HAS TRACKED SOUTHWARD AT 5 KNOTS OVER THE PAST 6 HOURS. THE WARNING POSITION IS BASED UPON A 060530Z4 VISIBLE SATELLITE IMAGE AND IS CONSISTANT WITH AN 060018Z5 MICROWAVE IMAGE. THE WARNING INTENSITY IS BASED UPON A SATELLITE CURRENT INTENSITY ESTIMATE OF 35 KNOTS. TROPICAL CYCLONE 05S (BILLY) CONTINUES TO DISSIPATE OVER WATER AS IT TRACKS SOUTHWARD OVER THE NORTHWESTERN COAST OF AUSTRALIA. THE ANIMATED INFRARED, VISIBLE, AND WATER VAPOR SATELLITE IMAGERY CONTINUE TO SHOW A RAPIDLY WEAKENING SYSTEM MOVING JUST OFF THE COAST. THE 060000Z6 UW-CIMSS WIND SHEAR CHARTS SHOW MODERATE TO SEVERE VERTICAL WIND SHEAR DIRECTLY OVER TC 05S (BILLY) AND CONTINUING TO THE SOUTHEAST. DUE TO THE HIGH SHEAR ENVIRONMENT, TC 05S (BILLY) CONTINUES TO RAPIDLY DISSIPATE OVER WATER AND WILL CONTINUE TO DISSIPATE AS IT TRACKS OVER THE AUSTRALIAN MAINLAND. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 060600Z2 IS 12 FEET. NEXT WARNINGS AT 061500Z2 (DTG 061351Z6), 062100Z9 (DTG 061951Z2) AND 070300Z0 (DTG 070151Z4). REFER TO TROPICAL CYCLONE 06S WARNINGS (WTXS32 PGTW)FOR TWELVE-HOURLY UPDATES.// ========================================================================= WTXS31 PGTW 981206 15:00z 1. TROPICAL CYCLONE 05S (BILLY) WARNING NR 016 02 ACTIVE TROPICAL CYCLONES IN SOUTHERN HEMISPHERE MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE --- WARNING POSITION: 061200Z9 --- NEAR 22.6S0 115.6E3 MOVEMENT PAST SIX HOURS - 150 DEGREES AT 11 KTS POSITION ACCURATE TO WITHIN 060 NM POSITION BASED ON CENTER LOCATED BY SATELLITE PRESENT WIND DISTRIBUTION: MAX SUSTAINED WINDS - 025 KT, GUSTS 035 KT DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND REPEAT POSIT: 22.6S0 115.6E3 --- FORECASTS: 12 HRS, VALID AT: 070000Z7 --- 24.1S7 116.1E9 MAX SUSTAINED WINDS - 020 KT, GUSTS 030 KT DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER LAND --- REMARKS: 061500Z2 POSITION NEAR 23.0S5 115.7E4. FINAL WARNING FOR TC 05S (BILLY). TC 05S MADE LANDFALL NEAR ONSLOW, AUSTRALIA AROUND 060630Z5. SYNOPTIC DATA INDICATES MAX SUSTAINED (ONE MINUTE AVERAGE) WINDS WERE 30KTS. TROPICAL CYCLONE 05S (BILLY) HAS TRACKED SOUTH-SOUTHEASTWARD AT 11 KNOTS OVER THE PAST 6 HOURS. TC 05S (BILLY) INCREASED FORWARD MOVEMENT AS IT BECAME SHEARED AND NOW EXISTS AS A LOW-LEVEL FEATURE WITH ISOLATED CONVECTION. THE WARNING POSITION AND INTENSITY (25KTS) ARE BASED UPON 061130Z1 INFRARED SATELLITE IMAGERY ANALYSIS TECHNIQUES AND SYNOPTIC DATA INTERPRETATION. ANIMATED INFRARED SATELLITE IMAGERY SHOWS TROPICAL CYCLONE 05S (BILLY) CONTINUES TO DISSIPATE AS IT TRACKS SOUTH- SOUTHEASTWARD OVER NORTHWESTERN AUSTRALIA. THE REMNANTS OF TC 05S (BILLY) SHOULD CONTINUE TO MOVE SOUTH-SOUTHEASTWARD WITH THE WEAK LOW-LEVEL STEERING FLOW ASSOCIATED WITH THE HIGH PRESSURE RIDGE TO THE SOUTHEAST. TC 05S HAS CONTINUED TO WEAKEN DUE TO MODERATE TO STRONG VERTICAL WINDSHEAR AND LAND INTERACTION. THE COMBINATION OF THIS WINDSHEAR AND LAND EFFECTS HAVE CAUSED TC 05S (BILLY) TO DISSIPATE AS A SIGNIFICANT TROPICAL CYCLONE. 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. REFER TO TROPICAL CYCLONE 06S (NONAME) WARNINGS (WTXS32 PGTW) FOR TWELVE-HOURLY UPDATES.//
Document: billy.htm
Updated: 26th December 2006 |
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