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TD 24W(KOMPASU) Final Warning/ TS 23W(NAMTHEUN) taking on Subtropical features/TD 16E(PAMELA) Final Warning,14/09utc



JTWC IS ISSUING 6HOURLY WARNINGS ON TD 23W. FINAL WARNING ON TD 24W WAS ISSUED AT 14/09UTC. 3 HOURLY SATELLITE BULLETINS ARE ISSUED ON BOTH SYSTEMS.
JTWC IS ISSUING 6HOURLY WARNINGS ON TD 23W. FINAL WARNING ON TD 24W WAS ISSUED AT 14/09UTC. 3 HOURLY SATELLITE BULLETINS ARE ISSUED ON BOTH SYSTEMS.


WESTERN NORTH PACIFIC: TD 23W(NAMTHEUN). WARNING 18 ISSUED AT 14/09UTC

FORECAST REASONING.  SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING.  FORECAST DISCUSSION: TD NAMTHEUN WILL CONTINUE ON ITS CURRENT TRACK FOR THE DURATION OF THE FORECAST UNDER THE STEERING INFLUENCE OF THE SUBTROPICAL RIDGE(STR). THE MARGINAL ENVIRONMENT WILL SUSTAIN THE CURRENT INTENSITY FOR UP TO 24H. AFTERWARD, INCREASING VERTICAL WIND SHEAT AND COOLING SSTS WILL GRADUALLY ERODE THE SYSTEM TOWARD DISSIPATION BY 48H, POSSIBLY SOONER. CONCURRENTLY, THE CYCLONE WILL CONTINUE TO GAIN MORE SUBTROPICAL CHARACTERISTICS.
FORECAST REASONING. SIGNIFICANT FORECAST CHANGES: THERE ARE NO SIGNIFICANT CHANGES TO THE FORECAST FROM THE PREVIOUS WARNING. FORECAST DISCUSSION: TD NAMTHEUN WILL CONTINUE ON ITS CURRENT TRACK FOR THE DURATION OF THE FORECAST UNDER THE STEERING INFLUENCE OF THE SUBTROPICAL RIDGE(STR). THE MARGINAL ENVIRONMENT WILL SUSTAIN THE CURRENT INTENSITY FOR UP TO 24H. AFTERWARD, INCREASING VERTICAL WIND SHEAT AND COOLING SSTS WILL GRADUALLY ERODE THE SYSTEM TOWARD DISSIPATION BY 48H, POSSIBLY SOONER. CONCURRENTLY, THE CYCLONE WILL CONTINUE TO GAIN MORE SUBTROPICAL CHARACTERISTICS.
2321100718 142N1671E  15
2321100800 145N1664E  15
2321100806 148N1658E  15
2321100812 151N1651E  15
2321100818 154N1643E  15
2321100900 160N1637E  20
2321100906 164N1628E  20
2321100912 166N1620E  20
2321100918 168N1615E  20
2321101000 170N1603E  30
2321101006 172N1599E  35
2321101012 174N1595E  40
2321101018 180N1584E  45
2321101100 182N1574E  50
2321101106 185N1561E  45
2321101112 186N1551E  45
2321101118 189N1541E  45
2321101200 191N1530E  40
2321101206 193N1522E  40
2321101212 199N1518E  35
2321101218 207N1519E  35
2321101300 216N1523E  30
2321101306 224N1529E  30
2321101312 231N1539E  30
2321101318 236N1547E  30
2321101400 239N1564E  30
2321101406 242N1572E  30
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TD 24W(KOMPASU) Final Warning/ TS 23W(NAMTHEUN) taking on Subtropical features/TD 16E(PAMELA) Final Warning,14/09utc


SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A MEDIUM-SIZED SYSTEM WITH PERSISTENT CONVECTION OVER THE CENTRAL DENSE OVERCAST (CDO) THAT IS TRAILING A FEEDER BAND SOUTHWARD. THE INITIAL POSITION  IS PLACED WITH MEDIUM CONFIDENCE BASED ON LOW CLOUD LINE TRACING  INTO THE OBSCURED LOW LEVEL CIRCULATION (LLC) AND EXTRAPOLATION FROM  A WEAK LLC FEATURE IN THE 140232Z AMSR MICROWAVE IMAGE THE INITIAL  INTENSITY OF 30KNOTS IS ASSIGNED WITH MEDIUM CONFIDENCE BASED ON AN  OVERALL ASSESSMENT OF AGENCY AND AUTOMATED DVORAK ESTIMATES AND  REFLECTS THE 6-HR PERSISTENT CONVECTIVE SIGNATURE OF THE SYSTEM.  ANALYSIS INDICATES A MARGINAL ENVIRONMENT WITH STRONG EQUATORWARD  OUTFLOW AND WARM SST OFFSET BY STRONG VWS. THE SYSTEM HAS BEGUN TO  EXHIBIT SUBTROPICAL CHARACTERISTICS, I.E., ASYMMETRIC WIND FIELD AND  VORTICITY SIGNATURE AND THE CDO OFFSET EASTWARD AND POLEWARD OF THE  LLC. THE CYCLONE IS TRACKING ON THE POLEWARD SIDE OF THE STR TO THE  SOUTH.
SATELLITE ANALYSIS, INITIAL POSITION AND INTENSITY DISCUSSION: ANIMATED MULTISPECTRAL SATELLITE IMAGERY (MSI) SHOWS A MEDIUM-SIZED SYSTEM WITH PERSISTENT CONVECTION OVER THE CENTRAL DENSE OVERCAST (CDO) THAT IS TRAILING A FEEDER BAND SOUTHWARD. THE INITIAL POSITION IS PLACED WITH MEDIUM CONFIDENCE BASED ON LOW CLOUD LINE TRACING INTO THE OBSCURED LOW LEVEL CIRCULATION (LLC) AND EXTRAPOLATION FROM A WEAK LLC FEATURE IN THE 140232Z AMSR MICROWAVE IMAGE THE INITIAL INTENSITY OF 30KNOTS IS ASSIGNED WITH MEDIUM CONFIDENCE BASED ON AN OVERALL ASSESSMENT OF AGENCY AND AUTOMATED DVORAK ESTIMATES AND REFLECTS THE 6-HR PERSISTENT CONVECTIVE SIGNATURE OF THE SYSTEM. ANALYSIS INDICATES A MARGINAL ENVIRONMENT WITH STRONG EQUATORWARD OUTFLOW AND WARM SST OFFSET BY STRONG VWS. THE SYSTEM HAS BEGUN TO EXHIBIT SUBTROPICAL CHARACTERISTICS, I.E., ASYMMETRIC WIND FIELD AND VORTICITY SIGNATURE AND THE CDO OFFSET EASTWARD AND POLEWARD OF THE LLC. THE CYCLONE IS TRACKING ON THE POLEWARD SIDE OF THE STR TO THE SOUTH.


MODEL DISCUSSION: NUMERICAL MODELS ARE IN VERY TIGHT AGREEMENT, GRADUALLY SPREADING TO 180KM AT 48H, LENDING HIGH CONFIDENCE TO THE JTWC TRACK FORECAST. HOWEVER, THERE IS ONLY MEDIUM CONFIDENCE THE INTENSITY FORECAST GIVEN THE UNCERTAINTY IN THE SUBTROPICAL TRANSITION.
MODEL DISCUSSION: NUMERICAL MODELS ARE IN VERY TIGHT AGREEMENT, GRADUALLY SPREADING TO 180KM AT 48H, LENDING HIGH CONFIDENCE TO THE JTWC TRACK FORECAST. HOWEVER, THERE IS ONLY MEDIUM CONFIDENCE THE INTENSITY FORECAST GIVEN THE UNCERTAINTY IN THE SUBTROPICAL TRANSITION.


WESTERN NORTH PACIFIC/SOUTH CHINA SEA: TS 24W(KOMPASU). WARNING 18/FINAL ISSUED AT 14/09UTC

140900Z POSITION NEAR 19.5N 106.4E. 14OCT21. TROPICAL DEPRESSION 24W (KOMPASU), LOCATED APPROXIMATELY 101 NM SOUTH-SOUTHEAST OF HANOI, VIETNAM, HAS TRACKED WEST- NORTHWESTWARD AT 15 KM/H OVER THE PAST SIX HOURS. ANIMATED  MULTISPECTRAL SATELLITE IMAGERY SHOWS THE SYSTEM IS COMPLETELY  STRIPPED OF ANY DEEP CONVECTION, FULLY EXPOSING A RAGGED AND WEAK  LOW LEVEL CIRCULATION WHERE THE INITIAL POSITION IS PLACED WITH HIGH  CONFIDENCE. THE INITIAL INTENSITY IS BASED ON OVERALL ASSESSMENT OF  AGENCY DVORAK ESTIMATES AND EXTRAPOLATED FROM NEARBY SURFACE  OBSERVATIONS. ENVIRONMENTAL ANALYSIS INDICATES MEDIUM (15-20KT)  VERTICAL WIND SHEAR, GREATLY DIMINISHED OUTFLOW, AND DRY AIR  ENTRAINMENT FROM THE NORTHWEST HAVE DRASTICALLY ERODED THE  ASSOCIATED CONVECTION. THIS IS THE FINAL WARNING ON THIS SYSTEM BY  THE JOINT TYPHOON WRNCEN PEARL HARBOR HI.
140900Z POSITION NEAR 19.5N 106.4E. 14OCT21. TROPICAL DEPRESSION 24W (KOMPASU), LOCATED APPROXIMATELY 101 NM SOUTH-SOUTHEAST OF HANOI, VIETNAM, HAS TRACKED WEST- NORTHWESTWARD AT 15 KM/H OVER THE PAST SIX HOURS. ANIMATED MULTISPECTRAL SATELLITE IMAGERY SHOWS THE SYSTEM IS COMPLETELY STRIPPED OF ANY DEEP CONVECTION, FULLY EXPOSING A RAGGED AND WEAK LOW LEVEL CIRCULATION WHERE THE INITIAL POSITION IS PLACED WITH HIGH CONFIDENCE. THE INITIAL INTENSITY IS BASED ON OVERALL ASSESSMENT OF AGENCY DVORAK ESTIMATES AND EXTRAPOLATED FROM NEARBY SURFACE OBSERVATIONS. ENVIRONMENTAL ANALYSIS INDICATES MEDIUM (15-20KT) VERTICAL WIND SHEAR, GREATLY DIMINISHED OUTFLOW, AND DRY AIR ENTRAINMENT FROM THE NORTHWEST HAVE DRASTICALLY ERODED THE ASSOCIATED CONVECTION. THIS IS THE FINAL WARNING ON THIS SYSTEM BY THE JOINT TYPHOON WRNCEN PEARL HARBOR HI.
PEAK INTENSITY WAS 55 KNOTS.
2421100718 156N1379E  15
2421100800 161N1368E  20
2421100806 167N1358E  20
2421100812 171N1348E  20
2421100818 172N1335E  30
2421100900 163N1315E  30
2421100906 157N1303E  25
2421100912 151N1295E  25
2421100918 154N1288E  25
2421101000 167N1284E  25
2421101006 175N1279E  35
2421101012 184N1266E  45
2421101018 186N1250E  45
2421101100 187N1241E  45
2421101106 188N1230E  50
2421101112 189N1217E  55
2421101118 188N1205E  55
2421101200 188N1190E  55
2421101206 188N1175E  55
2421101212 188N1162E  55
2421101218 191N1145E  55
2421101300 191N1127E  55
2421101306 192N1107E  55
2421101312 194N1090E  45
2421101318 193N1082E  45
2421101400 192N1075E  30
2421101406 195N1067E  25
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EASTERN NORTH PACIFIC: TD 16E(PAMELA). WARNING 16/FINAL ISSUED AT 14/04UTC

PEAK INTENSITY WAS 70 KNOTS/CAT 1.
1621100712  95N 844W  15
1621100718  95N 859W  15
1621100800  95N 874W  15
1621100806  96N 891W  15
1621100812  98N 907W  20
1621100818 101N 923W  25
1621100900 105N 939W  25
1621100906 109N 953W  25
1621100912 113N 964W  25
1621100918 125N 987W  25
1621101000 133N1007W  25
1621101006 140N1023W  30
1621101012 146N1038W  35
1621101018 152N1052W  40
1621101100 157N1063W  45
1621101106 162N1074W  45
1621101112 166N1079W  55
1621101118 170N1083W  60
1621101200 176N1088W  60
1621101206 187N1090W  65
1621101212 197N1092W  70
1621101218 206N1093W  60
1621101300 215N1089W  60
1621101306 223N1082W  65
1621101312 237N1068W  65
1621101318 251N1048W  40
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Rédigé par PATRICK HOAREAU le Thursday, October 14th 2021 à 10:32