WTXS51 PGTW 072100 WARNING ATCG MIL 17S SIO 190307194009 2019030718 17S HALEH 023 01 190 12 SATL 060 T000 282S 0670E 050 R050 085 NE QD 085 SE QD 085 SW QD 050 NW QD R034 160 NE QD 250 SE QD 225 SW QD 110 NW QD T012 304S 0662E 045 R034 240 NE QD 270 SE QD 200 SW QD 140 NW QD T024 330S 0652E 040 R034 220 NE QD 240 SE QD 190 SW QD 130 NW QD T036 355S 0653E 035 R034 190 NE QD 170 SE QD 150 SW QD 120 NW QD T048 381S 0671E 030 AMP 024HR DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER 036HR DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER 048HR DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER SUBJ: TROPICAL CYCLONE 17S (HALEH) WARNING NR 023 1. TROPICAL CYCLONE 17S (HALEH) WARNING NR 023 01 ACTIVE TROPICAL CYCLONE IN SOUTHIO MAX SUSTAINED WINDS BASED ON ONE-MINUTE AVERAGE WIND RADII VALID OVER OPEN WATER ONLY --- WARNING POSITION: 071800Z --- NEAR 28.2S 67.0E MOVEMENT PAST SIX HOURS - 190 DEGREES AT 12 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 WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 050 KT WINDS - 085 NM NORTHEAST QUADRANT 085 NM SOUTHEAST QUADRANT 085 NM SOUTHWEST QUADRANT 050 NM NORTHWEST QUADRANT RADIUS OF 034 KT WINDS - 160 NM NORTHEAST QUADRANT 250 NM SOUTHEAST QUADRANT 225 NM SOUTHWEST QUADRANT 110 NM NORTHWEST QUADRANT REPEAT POSIT: 28.2S 67.0E --- FORECASTS: 12 HRS, VALID AT: 080600Z --- 30.4S 66.2E MAX SUSTAINED WINDS - 045 KT, GUSTS 055 KT WIND RADII VALID OVER OPEN WATER ONLY RADIUS OF 034 KT WINDS - 240 NM NORTHEAST QUADRANT 270 NM SOUTHEAST QUADRANT 200 NM SOUTHWEST QUADRANT 140 NM NORTHWEST QUADRANT VECTOR TO 24 HR POSIT: 200 DEG/ 14 KTS --- 24 HRS, VALID AT: 081800Z --- 33.0S 65.2E MAX SUSTAINED WINDS - 040 KT, GUSTS 050 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 034 KT WINDS - 220 NM NORTHEAST QUADRANT 240 NM SOUTHEAST QUADRANT 190 NM SOUTHWEST QUADRANT 130 NM NORTHWEST QUADRANT VECTOR TO 36 HR POSIT: 180 DEG/ 13 KTS --- 36 HRS, VALID AT: 090600Z --- 35.5S 65.3E MAX SUSTAINED WINDS - 035 KT, GUSTS 045 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATING AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER RADIUS OF 034 KT WINDS - 190 NM NORTHEAST QUADRANT 170 NM SOUTHEAST QUADRANT 150 NM SOUTHWEST QUADRANT 120 NM NORTHWEST QUADRANT VECTOR TO 48 HR POSIT: 150 DEG/ 15 KTS --- EXTENDED OUTLOOK: 48 HRS, VALID AT: 091800Z --- 38.1S 67.1E MAX SUSTAINED WINDS - 030 KT, GUSTS 040 KT WIND RADII VALID OVER OPEN WATER ONLY DISSIPATED AS A SIGNIFICANT TROPICAL CYCLONE OVER WATER --- REMARKS: 072100Z POSITION NEAR 28.7S 66.8E. TROPICAL CYCLONE 17S (HALEH), LOCATED APPROXIMATELY 719 NM SOUTHEAST OF PORT LOUIS, MAURITIUS, HAS TRACKED SOUTHWARD AT 12 KNOTS OVER THE PAST SIX HOURS. ANIMATED ENHANCED INFRARED SATELLITE IMAGERY DEPICTS A RAPIDLY WEAKENING SYSTEM, WITH DECAYING CONVECTION AND AN OBSCURED LOW LEVEL CENTER (LLC). A 071635Z BULLSEYE ASCAT PASS SUPPORTED PLACEMENT OF THE INITIAL POSITION WITH HIGH CONFIDENCE. THE INITIAL INTENSITY IS ASSESSED AT 50 KNOTS, BASED ON AN ASSESSMENT OF MULTI-AGENCY DVORAK CURRENT INTENSITY ESTIMATES OF T3.0 (45 KNOTS), HEDGED SLIGHTLY HIGHER BASED ON AN ADVANCED DVORAK TECHNIQUE ESTIMATE OF T3.2 (42 KNOTS) AND A SATCON ESTIMATE OF 60 KNOTS. THE OVERALL ENVIRONMENT IS CURRENTLY UNFAVORABLE AND BECOMING INCRESAINGLY SO OVER TIME, WITH HIGH (25-30 KNOTS) VWS, AND COOL SSTS AT OR JUST SLIGHTLY ABOVE 26 CELSIUS. UPPER-LEVEL POLEWARD OUTFLOW REMAINS ROBUST, BUT CONVERGENT NORTHWESTERLY FLOW IS PUTTING INCREASED PRESSURE ON THE NORTHWEST SIDE OF THE SYSTEM. THE SYSTEM IS CURRENTLY TRACKING SOUTHWARD ALONG THE WESTERN PERIPHERY OF A DEEP-LAYER STR TO THE EAST. A 071439Z SSMIS 37GHZ MICROWAVE IMAGE SHOWED THAT THE LLC IS BEGINNING TO DECOUPLE FROM THE UPPER-LEVEL CIRCULATION, INDICATIVE OF THE ONSET OF A RAPID DECAY SCENARIO. THUS, THIS FORECAST CHANGES THE OVERALL END-GAME SCENARIO FROM EXTRATROPICAL TRANSITION TO DISSIPATION AS THE SYSTEM BEGINS TO RAPIDLY DECAY WELL NORTH OF THE BAROCLINIC ZONE. AMSU THERMAL CROSS-SECTIONS FROM 211400Z SHOWED THAT THE SYSTEM IS BEGINNING TO SHOW SOME SIGNS OF TRANSITION TO A SUB-TROPICAL STATE BUT IT IS NOT EXPECTED TO COMPLETE THIS TRANSITION BEFORE DISSIPATION. TC 17S WILL CONTINUE TRACKING SOUTHWWARD THROUGH TAU 24, BEFORE TURNING SOUTHEASTWARD THROUGH THE END OF THE FORECAST PERIOD, AS THE STR TO THE EAST WEAKENS AND RETREATS. NUMERICAL MODEL GUIDANCE IS IN VERY GOOD AGREEMENT ON THE TRACK THROUGH TAU 48, LENDING HIGH CONFIDENCE TO THE OFFICIAL FORECAST TRACK. MAXIMUM SIGNIFICANT WAVE HEIGHT AT 071800Z IS 25 FEET. NEXT WARNINGS AT 080300Z, 080900Z, 081500Z AND 082100Z.// 1719022818 92S 780E 20 1719030100 97S 778E 25 1719030106 100S 769E 25 1719030112 104S 763E 25 1719030118 108S 757E 30 1719030200 114S 754E 30 1719030206 120S 749E 40 1719030212 125S 742E 45 1719030218 132S 740E 55 1719030218 132S 740E 55 1719030300 139S 737E 60 1719030300 139S 737E 60 1719030306 146S 736E 65 1719030306 146S 736E 65 1719030306 146S 736E 65 1719030312 156S 737E 70 1719030312 156S 737E 70 1719030312 156S 737E 70 1719030318 163S 735E 75 1719030318 163S 735E 75 1719030318 163S 735E 75 1719030400 171S 733E 90 1719030400 171S 733E 90 1719030400 171S 733E 90 1719030406 180S 730E 105 1719030406 180S 730E 105 1719030406 180S 730E 105 1719030412 187S 726E 105 1719030412 187S 726E 105 1719030412 187S 726E 105 1719030418 191S 725E 115 1719030418 191S 725E 115 1719030418 191S 725E 115 1719030500 196S 724E 110 1719030500 196S 724E 110 1719030500 196S 724E 110 1719030506 204S 722E 100 1719030506 204S 722E 100 1719030506 204S 722E 100 1719030512 211S 717E 95 1719030512 211S 717E 95 1719030512 211S 717E 95 1719030518 217S 714E 90 1719030518 217S 714E 90 1719030518 217S 714E 90 1719030600 223S 709E 85 1719030600 223S 709E 85 1719030600 223S 709E 85 1719030606 230S 700E 80 1719030606 230S 700E 80 1719030606 230S 700E 80 1719030612 236S 691E 75 1719030612 236S 691E 75 1719030612 236S 691E 75 1719030618 243S 685E 75 1719030618 243S 685E 75 1719030618 243S 685E 75 1719030700 251S 681E 70 1719030700 251S 681E 70 1719030700 251S 681E 70 1719030706 260S 677E 65 1719030706 260S 677E 65 1719030706 260S 677E 65 1719030712 270S 673E 60 1719030712 270S 673E 60 1719030718 282S 670E 50 1719030718 282S 670E 50 NNNN